Lexus Car Fault Codes DTC LEXUS Car Fault Codes DTC

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DIAGNOSTICS

ENGINE DI–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–1. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–2. . .

PRE–CHECK DI–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–14. . . . . .

P ARTS LOCATION DI–18. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–19. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–21. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–22. . . . . . . . . . . . . . . . . . . . .

AUTOMATIC TRANSAXLE DI–142. . . . . . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–142. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–143. . .

PRE–CHECK DI–144. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–155. . . . . .

P ARTS LOCATION DI–157. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–158. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–160. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–163. . . . . . . . . . . . . . . . . . . . .

ABS & BA & TRC & VSC SYSTEM DI–203. . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–203. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–204. . .

PRE–CHECK DI–205. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–213. . . . . .

P ARTS LOCATION DI–216. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–217. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–220. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–222. . . . . . . . . . . . . . . . . . . . .

SUPPLEMENTAL RESTRAINT SYSTEM DI–303. . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–303. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–304. . .

PRE–CHECK DI–305. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–31 1. . . . . .

P ARTS LOCATION DI–314. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–315. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–317. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–318. . . . . . . . . . . . . . . . . . . . .

THEFT DETERRENT SYSTEM DI–443. . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–443. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–444. . .

PRE–CHECK DI–445. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

P ARTS LOCATION DI–450. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–451. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–452. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–453. . . . . . . . . . . . . . . . . . . . .

CRUISE CONTROL SYSTEM DI–472. . . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–472. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–473. . .

PRE–CHECK DI–474. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–479. . . . . .

P ARTS LOCATION DI–480. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–481. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–483. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–484. . . . . . . . . . . . . . . . . . . . .

ENGINE IMMOBILISER SYSTEM DI–520. . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–520. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–521. . .

PRE–CHECK DI–522. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–525. . . . . .

P ARTS LOCATION DI–526. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–527. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–528. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–529. . . . . . . . . . . . . . . . . . . . .

COMBINATION METER SYSTEM DI–537. . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–537. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–538. . .

PROBLEM SYMPTOMS TABLE DI–539. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–541. . . . . . . . . . . . . . . . . . . . .

SLIDING ROOF SYSTEM DI–553. . . . . . . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–553. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–554. . .

P ARTS LOCATION DI–555. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–556. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–557. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–558. . . . . . . . . . . . . . . . . . . . .

BODY CONTROL SYSTEM DI–564. . . . . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–564. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–565. . .

P ARTS LOCATION DI–566. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–567. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–570. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–572. . . . . . . . . . . . . . . . . . . . .

DRIVER DOOR CONTROL SYSTEM DI–598. . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–598. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–599. . .

P ARTS LOCATION DI–600. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–601. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–602. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–603. . . . . . . . . . . . . . . . . . . . .

PASSENGER DOOR CONTROL

SYSTEM DI–620. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–620. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–621. . .

P ARTS LOCATION DI–622. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–623. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–624. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–625. . . . . . . . . . . . . . . . . . . . .

REAR LEFT DOOR CONTROL SYSTEM DI–642. . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–642. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–643. . .

P ARTS LOCATION DI–644. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–645. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–647. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–648. . . . . . . . . . . . . . . . . . . . .

REAR RIGHT DOOR CONTROL

SYSTEM DI–659. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–659. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–660. . .

P ARTS LOCATION DI–661. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–662. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–664. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–665. . . . . . . . . . . . . . . . . . . . .

MULTIPLEX COMMUNICATION SYSTEM DI–676. .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–676. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–677. . .

PRE–CHECK DI–678. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–683. . . . . .

P ARTS LOCATION DI–685. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–686. . . . . . . . . . . . . . . . . . . . . .

CIRCUIT INSPECTION DI–688. . . . . . . . . . . . . . . . . . . . .

LEXUS NAVIGATION SYSTEM DI–726. . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–726. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–727. . .

PRE–CHECK DI–728. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–745. . . . . .

P ARTS LOCATION DI–751. . . . . . . . . . . . . . . . . . . . . . . . .

TERMINALS OF ECU DI–752. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–756. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–757. . . . . . . . . . . . . . . . . . . . .

AIR CONDITIONING SYSTEM DI–803. . . . . . . . . . . .

HOW TO PROCEED WITH

TROUBLESHOOTING DI–803. . . . . . . . . . . . . . . . . . . .

CUSTOMER PROBLEM ANALYSIS CHECK DI–804. . .

PRE–CHECK DI–805. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC TROUBLE CODE CHART DI–809. . . . . .

TERMINALS OF ECU DI–81 1. . . . . . . . . . . . . . . . . . . . . .

PROBLEM SYMPTOMS TABLE DI–812. . . . . . . . . . . . .

CIRCUIT INSPECTION DI–814. . . . . . . . . . . . . . . . . . . . .

DI–1

–DIAGNOSTICS ENGINE

ENGINE

DI4DW–13

HOW TO PROCEED WITH TROUBLESHOOTING

When using hand–held tester, troubleshooting in accordance with the procedure on the following page.

Vehicle Brought to Workshop

Titles inside are titles of pages in

this manual with the page number indicated

in the bottom portion. See the indicated

Customer Problem Analysis P. DI–2

Connect the hand–held tester to DLC3 P. DI–3

pages for detailed explanations.

If the display indicates a communication fault in the tool, inspect DLC3 P. DI–3

Check DTC and Freezed Frame Data (Precheck)

Record or Print DTC and Freezed Frame Data P. DI–3

Clear DTC and Freezed Frame Data P. DI–3

Visual Inspection

Setting the Check (Test) Mode Diagnosis P. DI–3

Problem Symptom Confirmation

If the engine does not start perform steps 10 and 12 first

Malfunction occurs.

DTC Check P. DI–3

Normal Malfunction code.

Basic Inspection P. DI–3

Parts Inspection

Identification of Problem

Adjustment, Repair

Confirmation Test

Malfunction does not occur.

Symptom Simulation P IN–22.

DTC Chart P. DI–14

Problem Symptom Table P. DI–21

Circuit Inspection P. DI–22 – DI–123

Check for Intermittent Problems P. DI–3

End

LEXUS RX300 (RM785E)

DI–2

–DIAGNOSTICS ENGINE

CUSTOMER PROBLEM ANALYSIS CHECK

DI4DX–02

ENGINE CONTROL SYSTEM Check Sheet

Customer’ s Name

Driver’s Name Data Vehicle

Brought in

License No.

Engine does not Start

Difficult to Start

Poor Idling

Poor Drivability

Problem Symptoms

Engine Stall

Others

Engine does not crank No initial combustion No complete combustion

Engine cranks slowly Other

Incorrect first idle Idling rpm is abnormal High ( rpm) Low ( rpm) Rough idling

Hesitation Back fire Muffler explosion (after–fire) Surging Knocking

Soon after starting After accelerator pedal depressed After accelerator pedal released Shifting from N to D

Other

Inspector’ s Name

Other

Model and Model Year

Frame No.

Engine Model

Odometer Reading

During A/C operation

km miles

Datas Problem Occurred

Problem Frequency

Weather

Outdoor Temperature

Place

Engine Temp.

Condition When

Problem Occurs

Engine Operation

Condition of check engine warning light (CHK ENG)

DTC Inspection

Constant Other

Fine Cloudy Rainy Snowy Various/Other

Hot

Highway Suburbs Inner City Uphill Downhill Rough road

Cold Starting

Driving A/C switch ON/OFF

Normal mode (Precheck)

Check Mode

Sometimes ( times per day/month) Once only

Warm Cool Cold (approx. °F/ °C)

Other

Warming up After Warming up Any temp. Other

Just after starting ( min.) Idling Racing Constant speed Acceleration Deceleration

Other

Remains on Sometimes light up Does not light up

Normal Malfunction code(s) (code )

Freezed frame data ( )

Normal Malfunction code(s) (code )

Freezed frame data ( )

LEXUS RX300 (RM785E)

FI2547

DI–3

–DIAGNOSTICS ENGINE

DI7O5–02

PRE–CHECK

1. DIAGNOSIS SYSTEM

(a) Description

 When troubleshooting Euro–OBD vehicles, the

only difference from the usual troubleshooting procedure is that you connect to the vehicle the OBD scan tool complying with ISO 15031–4 or hand– held tester, and read off various data output from the vehicle’s engine ECU.

 Euro–OBD regulations require that the vehicle’s

on–board computer lights up the check engine warning light on the instrument panel when the computer detects a malfunction in the emission control system / components or in the power train control components which affect vehicle emissions, or a malfunction in the computer. In addition to the check engine warning light lighting up when a malfunction is detected, the applicable Diagnostic Trouble Codes (DTC) prescribed by ISO 15031–4 are recorded in the engine ECU memory (See page DI–14). If the malfunction does not reoccur in 3 consecutive trips, the check engine warning light goes off automatically but the DTCs remain recorded in the engine ECU memory.

 When DTC P3190, P3191 are detected and the re-

main of the fuel is little, the computer judges the cause as a fuel shortage, and after the next trip, when the supply of fuel is confirmed, it turns off MIL, but the memory of DTC still remains.

DLC3

LEXUS RX300 (RM785E)

Hand–Held Tester

D09456

 To check the DTCs, connect the OBD scan tool or

hand–held tester to Data Link Connector 3 (DLC3) on the vehicle. The OBD scan tool or hand–held tester also enables you to erase the DTCs and check freezed frame data and various forms of engine data. (For operating instructions, see the OBD scan tool’s instruction book.) DTCs include ISO controlled codes and manufacturer controlled codes. ISO controlled codes must be set as prescribed by the ISO, while manufacturer controlled codes can be set freely by the manufacturer within the prescribed limits. (See DTC chart on page DI–14)

DI–4

–DIAGNOSTICS ENGINE

 The diagnosis system operates in normal mode

during normal vehicle use. It also has a check mode for technicians to simulate malfunction symptoms and troubleshoot. Most DTCs use 2 trip detection logic* to prevent erroneous detection, and ensure thorough malfunction detection. By switching the engine ECU to check mode when troubleshooting, the technician can cause the check engine warning light to light up for a malfunction that is only detected once or momentarily. (hand–held tester only) (See step 2)

 *2 trip detection logic: When a malfunction is 1st de-

tected, the malfunction is temporarily stored in the engine ECU memory. (1st trip) If the same malfunction is detected again during the second drive test, this 2nd detection causes the check engine warning light to light up. (2nd trip) (However, the IG switch must be turned OFF between the 1st trip and the 2nd trip.)

 Freeze frame data:

Freeze frame data records the engine condition when a misfire (DTCs P0300 – P0306) or fuel trim malfunction (DTCs P0171, P0172, P0174, P0175) or other malfunction (first malfunction only), is detected. Because freeze frame data records the engine conditions (fuel system, calculated load, engine coolant temperature, fuel trim, engine speed, vehicle speed, etc.) when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich,

etc. at the time of the malfunction. Priorities for troubleshooting: If troubleshooting priorities for multiple DTCs are given in the applicable DTC chart, these should be followed. If no instructions are given troubleshoot DTCs according to the following priorities.

(1) DTCs other than fuel trim malfunction (DTCs

P0171, P0172, P0174, P0175) and misfire (DTCs

P0300 – P0306).

(2) Fuel trim malfunction (DTCs P0171, P0172, P0174,

P0175).

(3) Misfire (DTCs P0300 – P0306).

LEXUS RX300 (RM785E)

1011121314

DLC3

456

DI–5

–DIAGNOSTICS ENGINE

(b) Check the DLC3.

The vehicle’s engine ECU uses the ISO 9141–2 communication protocol. The terminal arrangement of DLC3

A04550

complies with ISO 15031–03 and matches the ISO 9141–2 format.

Terminal No.

7 Bus ę Line / Pulse generation During transmission 4 Chassis Ground / ↔ Body Ground 1 Ω or less Always

16 Battery Positive / ↔ Body Ground 9 – 14 V Always

Connection / Voltage or Resistance Condition

HINT: If your display shows ”UNABLE TO CONNECT TO VEHICLE” when you have connected the cable of the OBD scan tool or hand–held tester to DLC3, turned the ignition switch ON and operated the hand–held tester, there is a problem on the vehicle side or tool side.

 If communication is normal when the tool is connected to

another vehicle, inspect DLC3 on the original vehicle.

 If communication is still not possible is when the tool is

connected to another vehicle, the problem is probably in the tool itself, so consult the Service Debarment listed in the tool,s instruction manual.

2. INSPECT DIAGNOSIS (Normal Mode)

(a) Check the check engine warning light.

(1) The check engine warning (CHK ENG) comes on

when the ignition switch is turned ON and the en-

gine is not running. HINT: If the check engine warning (CHK ENG) does not light up, troubleshoot the combination meter.

FI2547

(2) When the engine is started, the check engine warn-

ing light should go off. If the lamp remains on, the

diagnosis system has detected a malfunction or ab-

normality in the system (b) Check the DTC, using hand–held tester.

NOTICE: Hand–held tester only: When the diagnosis system is switched from normal mode to check (test) mode, it erases all DTCs and freezed frame data recorded in normal mode. So before switching modes, always check the DTCs and freezed frame data, and note them down.

LEXUS RX300 (RM785E)

DI–6

–DIAGNOSTICS ENGINE

(1) Prepare the hand–held tester. (2) Connect the hand–held tester to DLC3. (3) Turn the ignition switch ON and switch the hand–

held tester main switch ON.

(4) Use the hand–held tester to check the DTCs and

freezed frame data; note them down. (For operating

instructions, see the hand–held tester,s instruction

book.)

(5) See page DI–14 to confirm the details of the DTCs.

The following actions will erase the DTCs and freezed frame data.

 Operating the hand–held tester to erase the

codes. (See the hand–held tester ’s instruction book for operating instructions.)

 Disconnecting the battery terminals or EFI

fuse.

NOTICE: If the hand–held tester switches the engine ECU from normal mode to check mode or vice–versa, or if the ignition switch is turned from ON to ACC or OFF during check mode, the DTCs and freezed frame data will be erased.

3. INSPECT DIAGNOSIS (Check (Test) Mode)

HINT: Hand–held tester only: Compared to the normal mode, the check mode has an increased sensitivity to detect malfunctions. Furthermore, the same diagnostic items which are detected in the normal mode can also be detected in the check (test) mode. (a) Check the DTC.

(1) Initial conditions

 Battery positive voltage 11V or more.  Throttle valve fully closed.  Transmission in ”P” or ”N” position.  Air conditioning switched OFF.

(2) Turn ignition switch OFF. (3) Prepare the hand–held tester. (4) Connect the hand–held tester to DLC3 on the at the

lower left of the instrument panel.

(5) Turn the ignition switch ON and switch the push the

hand–held tester ON.

LEXUS RX300 (RM785E)

Flashing

OFF

0.13 Second

FI3605

DI–7

–DIAGNOSTICS ENGINE

(6) Switch the hand–held tester normal mode to check

(test) mode. (Check that the check engine warning

light (CHK ENG) flashes.)

(7) Start the engine. (The check engine warning (CHK

ENG) light goes out after the engine start.)

(8) Simulate the conditions of the malfunction de-

scribed by the customer.

NOTICE: Leave the ignition switch ON until you have checked the DTC, etc.

(9) After simulating the malfunction conditions, use the

hand–held tester diagnosis selector to check the

DTCs and freezed frame data, etc. HINT: T ake care not to turn the ignition switch OFF . T urning the ignition switch OFF switches the diagnosis system from check (test) mode to normal mode. so all DTCs, etc. are erased.

(10) After checking the DTCs, inspect the applicable cir-

cuit.

Interface Box

Vehicle Harness

(b) Using break–out–box and hand–held tester

(1) Hook up the break–out–box and hand–held tester

to the vehicle.

(2) Read the engine ECU input/output values following

Engine ECU

HINT:

the prompts on the tester screen.

Hand–held tester has a ”Snapshot” function. This records the measured values and is effective in the diagnosis of intermittent

Break–Out–Box

N09348

problems. Please refer to the hand–held tester/break–out–box operator,s manual for further details.

4. FAIL–SAFE CHART

If any of the following codes is recorded, the engine ECU enters fail–safe mode.

DTC No.

P0100  Ignition timing fixed at 10° BTDC Returned to normal condition P0110 Intake air temp. is fixed at 20°C (68°F) Returned to normal condition P0115 Water temp. is fixed at 80°(176°F) Returned to normal condition

P0120 VTA is fixed at 0°

P0325 P0300

P0500

P1300 P1305 P1310 P1315

Max. timing retardation IG switch OFF

High RPM for cut is prohibited ISC control prohibited

Fuel cut Feturned to normal condition

Fail–Safe Operation Fail–Safe Deactivation Conditions

The following condition must be repeated at least 2 times consecutively When closed throttle position switch is ON:

0.1 V x VTA and 0.95 V

Returned to normal condition

LEXUS RX300 (RM785E)

DI–8

–DIAGNOSTICS ENGINE

5. CHECK FOR INTERMITTENT PROBLEMS

HAND–HELD TESTER only: By putting the vehicle’s engine ECU in check (test) mode, 1 trip detection logic is possible instead of 2 trip detection logic and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.

(1) Clear the DTC (See step 3.). (2) Set the check (test) mode (See step 3.). (3) Perform a simulation test (See page IN–22). (4) Check the connector and terminal (See page IN–32). (5) Check the visual check and contact pressure (See page IN–32). (6) Handle the connector (See page IN–32).

6. BASIC INSPECTION

When the malfunction code is not confirmed in the DTC check, troubleshooting should be carried out in the order for all possible circuits to be considered as the causes of the problems. In many cases, by carrying out the basic engine check shown in the following flow chart, the location causing the problem can be found quickly and efficiently. Therefore, use of this check is essential in engine troubleshooting.

1 Is battery positive voltage 11V or more when engine is stopped ?

YES

2 Is engine cranked ?

YES

3 Does engine start ?

NO Charge or replace battery.

NO Proceed to problem table on page DI–21.

NO Go to step 7.

YES

LEXUS RX300 (RM785E)

4 Check air filter.

Outside

Inside

DI–9

–DIAGNOSTICS ENGINE

PREPARATION:

Remove the air filter.

CHECK:

Visually check that the air filter is not excessively dirty or oily. HINT: If necessary, clean the filter with compressed air . First blow from inside thoroughly, then blow from outside of filter.

P00495

NG Repair or replace.

5 Check engine idle speed.

DLC3

SST

9 (TAC)

Battery

Tachometer

A09031

PREPARATION:

(a) Warm up engine to normal operating temperature. (b) Switch off all accessories. (c) Switch off air conditioning. (d) Shift transmission into the ”P” position. (e) Connect the hand–held tester to DLC3 on the vehicle. (f) If you have no hand–held tester, connect tachometer test

prove to terminal 9 (TAC) of DLC3. SST 09843–18030

(g) Transit to inspection mode.

NOTICE: As some tachometer are not compatible with this ignition system, we recommend that you confirm the compatibility of your until before use. CHECK:

Check the idle speed.

OK:

Idle speed: 650 – 750 rpm

LEXUS RX300 (RM785E)

NG Proceed to problem symptoms table on page

DI–21.

DI–10

6 Check ignition timing.

–DIAGNOSTICS ENGINE

PREPARATION:

(a) Warm up engine to normal operating temperature. (b) Switch off all accessories. (c) Switch off air conditioning (d) Shift transmission into the ”P” position. (e) Using SST, connect terminals 13 (TC) and 4 (CG) of

DLC3. SST 09843–18040

(f) Using a timing light, connect the tester to No.1

high–tension cord.

(g) Transit to inspection mode.

CHECK:

Check ignition timing.

OK:

Ignition timing: 10° BTDC at idle

A04438 P12952

A14468

Proceed to problem symptoms table on page DI–21.

NG Proceed to page IG–1 and continue to trouble-

shoot.

LEXUS RX300 (RM785E)

7 Check fuel pressure.

BE6653 A02330

A10579

DI–11

–DIAGNOSTICS ENGINE

PREPARATION:

(a) Be sure that enough fuel is in the tank. (b) Turn the ignition switch ON. (c) Connect the hand–held tester to the DLC3. (d) Use ACTIVE TEST mode to operate the fuel pump. (e) If you have no hand–held tester, connect the positive (+)

and negative (–) leads from the battery to the fuel pump connector (See page FI–5 ).

CHECK:

Check that the pulsation damper screw rises up when the fuel pump operates.

NG Proceed to page FI–5, and continue to trouble-

shoot.

8 Check for spark.

PREPARATION:

(a) Remove ignition coil. (b) Remove the spark plug. (c) Install the spark plug to the ignition coil, and connect the ignition coil connector. (d) Disconnect the injector connector. (e) Be sure to ground the screw of the spark plug securely.

CHECK:

Check if spark occurs while engine is being cranked.

NOTICE: To prevent excess fuel being injected from the injectors during this test, don’t crank the engine for more than 5 – 10 seconds at a time.

NG Proceed to page IG–1 and continue to trouble-

shoot.

Proceed to problem symptoms table on page DI–21.

LEXUS RX300 (RM785E)

DI–12

–DIAGNOSTICS ENGINE

7. ENGINE OPERATING CONDITION NOTICE: The values given below for ”Normal Condition” are representative values, so a vehicle may still be normal even if its value from those listed here. So do not decide whether a part is faulty or not solely according to the ”Normal Condition” here.

Hand–held tester display

FUEL SYS #1

FUEL SYS #2

CALC LOAD

COOLANT TEMP Engine Coolant Temp. Sensor V alue After warming up: 80 – 95°C (176 – 203°F)

SHORT FT #1 Short–term Fuel Trim Bank 1 0 ± 20%

LONG FT #1 Long–term Fuel Trim Bank 1 0 ± 20%

SHORT FT #2 Short–term Fuel Trim Bank 2 0 ± 20%

LONG FT #2 Long–term Fuel Trim Bank 2 0 ± 20 %

ENGINE SPD Engine Speed Idling: 650 – 750 rpm

VEHICLE SPD V ehicle Speed Vehicle stopped: 0 km/h (0 mph)

IGN ADVANCE Ignition Advance: Ignition Timing of Cylinder No.1 Idling: BTDC 8 – 12°

INTAKE AIR Intake Air T emp. Sensor V alue Equivalent to Ambient T emp.

MAF Air Flow Rate Through Mass Air Flow Meter

THROTTLE POS

O2S B1 S2

A/FS B1 S1 Voltage Output of A/F Sensor Bank 1 Sensor 1 Idling: 2.8 – 3.8 V A/FS B2 S1 Voltage Output of A/F Sensor Bank 2 Sensor 1 Idling: 2.8 – 3.8 V

A/FFT B1 S1

A/FFT B2 S1

MISFIRE RPM Engine RPM for first misfire range Misfire 0: 0 rpm

MISFIRE LOAD Engine load for first misfire range Misfire 0: 0 g/r

INJECTOR Fuel injection time for cylinder No.1 Idling: 1.6 – 2.9 ms

MIL ON RUN DIST

IAC DUTY RATIO

STAR TER SIG Starter Signal Cranking: ON

CTP SIG Closed Throttle Position Signal Throttle fully closed: ON

A/C SIG A/C Switch Signal A/C ON: ON

PNP SW Park/Neutral Position Switch Signal P or N position: ON

ELCTRCL LOAD SIG Electrical Load Signal Defogger switch ON: ON

STOP LIGHT SW Stop Light Switch Signal Stop light switch ON: ON

LEXUS RX300 (RM785E)

Measurement Item Normal Condition*

Fuel System Bank 1 OPEN: Air–fuel ratio feedback stopped CLOSED: Air–fuel ratio feedback operating

Fuel System Bank 2 OPEN: Air–fuel ratio feedback stopped CLOSED: Air–fuel ratio feedback operating

Calculator Load: Current intake air volume as a proportion of max. intake air volume

Voltage Output of Throttle Position Sensor Calculated as a percentage: 0 V → 0 %, 5 V → 100 %

Voltage Output of Oxygen Sensor Bank 1, Sensor 2

A/F Sensor Fuel Trim Bank 1, Sensor 1 (Same as SHORT FT #1)

A/F Sensor Fuel Trim Bank 2, Sensor 1 (Same as SHORT FT #1)

Distance since activation of check engine warning light

Intake Air Control Valve Duty Ratio Opening ratio rotary solenoid type IAC valve

Idling after warming up: CLOSED

Idling: 13.1 – 18.7 % Racing without load (2,500rpm): 11.7 – 17.3 %

Idling: 3.3 – 4.7 gm/sec. Racing without load (2,500 rpm):

10.4 – 15.4 gm/sec. Throttle valve fully closed: 7 – 11 %

Throttle valve fully open: 65 – 75 %

Driving 50 km/h (31 mph): 0.05 – 0.95 V

0 ± 20 %

When there is no DTC: 0 km (0 mile)

Idling: 27 – 47 %

–DIAGNOSTICS ENGINE

DI–13

PS OIL PRESS SW

FC IDL

FC TAU Fuel Cut TAU: Fuel cut during very light load Fuel cut operating: ON

CYL#1 – CYL#6 Abnormal revolution variation for each cylinder 0 %

IGNITION

INTAKE CTRL VSV Intake Air Control Valve VSV Signal VSV operating: ON

A/C CUT SIG A/C Cut Signal A/C S/W OFF: ON

FUEL PUMP Fuel Pump Signal Idling: ON EVAP (PURGE) VSV EVAP VSV Signal VSV operating: Above 30 % VAPOR PRESS VSV Vapor Pressure VSV Signal VSV operating: ON

TOT AL FT B1

TOT AL FT B2

: If no conditions are specifically stated for ”ldling”, it means the shift lever is at P position, the A/C switch

Power Steering Oil Pressure Switch Signal Turn steering wheel: ON Fuel Cut Idle: Fuel cut when throttle valve fully

closed, during deceleration

T otal number of ignition for every 1,000 revolutions

Total Fuel Trim Bank 1: Average value for fuel trim system of bank 1

Total Fuel Trim Bank 1: Average value for fuel trim system of bank 2

Fuel cut operating: ON

0 – 3,000

Idling: 0.8 – 1.2

is OFF and all accessory switches are OFF.

LEXUS RX300 (RM785E)

DI–14

–DIAGNOSTICS ENGINE

DI12C–22

DIAGNOSTIC TROUBLE CODE CHART

SAE CONTROLLED

HINT: Parameters listed in the chart may not be exactly the same as your reading due to the type of instrument or other factors. If a malfunction code is displayed during the DTC check in check mode, check the circuit for that code listed in the table below. For details of each code, turn to the page referred to under the ’ ’See page ’’ for the respective ’’DTC No.’’ in the DTC chart.

DTC No.

(See Page)

P0100

(DI–22)

P0101

(DI–26)

P0110

(DI–26)

P0115

(DI–31)

P0116

(DI–35)

P0120

(DI–36)

P0121

(DI–41)

P0125

(DI–42)

P0136

(DI–48)

P0141

(DI–50)

P0171

(DI–52)

P0172

(DI–52)

Detection Item Trouble Area

Mass Air Flow Circuit Malfunction

Mass Air Flow Circuit Range/ Performance Problem

Intake Air T emp. Circuit Malfunction

Engine Coolant T emp. Circuit Malfunction

Engine Coolant T emp. Circuit Range/Performance Probrem

Throttle/Pedal Position Sensor/ Switch ”A” Circuit Malfunction

Throttle/Pedal Position Sensor/ Switch ”A” Circuit Range/Performance Problem

Insufficient Coolant Temp. for Closed Loop Fuel Control

Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)

Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

Fuel Trim System too Lean (A/F Lean Malfunction, Bank 1)

System too Rich (A/F Rich Malfunction Bank 1)

CHK

ENG*

 Open or short in air flow meter circuit  Air flow meter  Engine ECU

 Air flow meter  

 Open or short in intake air temp. sensor circuit  Intake air temp. sensor (built into air flow meter)  Engine ECU

 Open or short in water temp. sensor circuit  Water temp. sensor  Engine ECU

 Engine coolant temp. sensor  Cooling system

 Open or short in throttle position sensor circuit  Throttle position sensor  Engine ECU

 Throttle position sensor  

 Air induction system  Fuel pressure  Injector injection  Gas leakage on exhaust system  Open or short in heated oxygen sensor (bank 1 sensor 1)

circuit

 Oxygen sensor (bank 1 sensor 1)  Open or short in heater circuit of oxygen sensor

 Oxygen sensor

 Same as DTC No. P0135  

 Air intake (hose loose)  Fuel line pressure  Injector blockage  Oxygen sensor malfunction  Air flow meter  Water temp. sensor

 Fuel line pressure  Injector leak, blockage  Heated oxygen sensor malfunction  Mass air flow meter  Engine coolant temp. sensor  Gas leakage on exhaust system

 

Memory

LEXUS RX300 (RM785E)

P0174

Injector

Air fl

Oen or short in engine wire

(DI–52)

P0175

(DI–52)

P0300

(DI–57)

P0301

(DI–57)

P0302

(DI–57)

P0303

(DI–57)

P0304

(DI–57)

P0305

(DI–57)

P0306

(DI–57)

P0325

(DI–63)

P0330

(DI–63)

P0335

(DI–67)

P0340

(DI–69)

P0420

(DI–71)

P0443

(DI–74)

P0500

(DI–77)

P0505

(DI–80)

P1130

(DI–85)

System too Lean (A/F Lean Malfunction Bank 2)

System too Rich (A/F Rich Malfunction Bank 2)

Random/Multiple Cylinder Misfire Detected

Cylinder 1 Misfire Detected

Cylinder 2 Misfire Detected

Cylinder 3 Misfire Detected

Cylinder 4 Misfire Detected

Cylinder 5 Misfire Detected

Cylinder 6 Misfire Detected

Knock Sensor 1 Circuit Malfunction

Knock Sensor 2 Circuit Malfunction (Bank 2)

Crankshaft Position Sensor ”A” Circuit Malfunction

Camshaft Position Sensor Circuit Malfunction

Catalyst System Efficiency Below Threshould (Bank 1)

Evaporative Emission Control System Purge Control Vent Control Malfunction

Vehicle Speed Sensor Malfunction

Idle Control System Malfunction

A/F Sensor Circuit Range/Perfor-

mance Malfunction (Bank 1 Sensor 1)

–DIAGNOSTICS ENGINE

Same as DTC No. P0171  

Same as DTC No. P0172  

 Ignition system  Injector  Fuel pressure  Compression pressure  Valve clearance  Valve timing



ow meter

 

 Water temp. sensor  Open or short in engine wire  Connector connection  Engine ECU

 Open or short in knock sensor 1 circuit  Knock sensor 1 (looseness)

 

 Engine ECU  Open or short in knock sensor 2 circuit

 Knock sensor 2 (looseness)

 

 Engine ECU  Open or short in crankshaft position sensor circuit

 Crankshaft position sensor  Signal plate

 

 Engine ECU  Open or short in camshaft position sensor circuit

 Camshaft position sensor

 

 Engine ECU  Gas leakage on exhaust system

 Oxygen sensor

 

 Three–way catalytic converter  Open or short in VSV circuit for EVAP

 VSV for EVAP

 

 Engine ECU  Combination meter

 Open or short in No.1 vehicle speed sensor circuit  Engine ECU

 

 No.1 vehicle speed sensor  Open or short in ISC valve circuit

 ISC valve is stuck or closed  Open or short in A/C signal circuit

 

 Air induction system  Engine ECU

 Open or short in A/F sensor circuit  A/F sensor  Air induction system  Fuel pressure

 

 Injector  Engine ECM

DI–15

LEXUS RX300 (RM785E)

DI–16

P1133

(DI–90)

P1135

(DI–94)

P1150

(DI–85)

P1153

(DI–90)

P1155

(DI–94)

P1300

(DI–96)

P1305

(DI–96)

P1310

(DI–96)

P1315

(DI–96)

P1320/14

(DI–96)

P1325/14

(DI–96)

P1335/13

(DI–101)

P1346

(DI–102)

P1349

(DI–103)

P1350

(DI–109)

A/F Sensor Circuit Response Malfunction (Bank 1 Sensor 1)

A/F Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)

A/F Sensor Circuit Range/Perfor-

mance Malfunction (Bank 2 Sensor 1)

A/F Sensor Circuit Response Malfunction (Bank 2 Sensor 1)

A/F Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

Igniter Circuit Malfunction (No.1)

Igniter Circuit Malfunction (No.2)

Igniter Circuit Malfunction (No.3)

Igniter Circuit Malfunction (No.4)

Igniter Circuit Malfunction (No.5)

Igniter Circuit Malfunction (No.6)

Crankshaft Position Sensor Circuit Malfunction (During engine running)

VVT Sensor Circuit Range/Performance Problem (Bank 1)

VVT System Malfunction (Bank 1)

VVT Sensor/Camshaft position Sensor Circuit Malfunction (Bank

–DIAGNOSTICS ENGINE

 Open or short in A/F sensor circuit  A/F sensor  Air induction system  Fuel pressure

 

 Injector  Engine ECM

 Open or short in heater circuit of A/F sensor  A/F sensor heater

 

 Engine ECM

 Same as DTC No. P1130  

 Same as DTC No. P1133  

 Same as DTC No. P1135  

 Open or short in IGF and IGT1 circuit from ignition coil with

igniter to Engine ECU

 No.1 ignition coil with igniter

 

 Engine ECU  Open or short in IGF or IGT2 circuit from No.2 ignition coil with

igniter to engine ECU

 No.2 ignition coil with igniter

 

 Engine ECU  Open or short in IGF and IGT3 circuit from ignition coil with

igniter to Engine ECU

 No.3 ignition coil with igniter

 

 Engine ECU  Open or short in IGF or IGT4 circuit from No.4 ignition coil with

igniter to engine ECU

 No.4 ignition coil with igniter

 

 Engine ECU  Ignition system

 Open or short in IGF or IGT5 circuit from igniter to engine ECU  Igniter

 

 Engine ECU  Ignition system

 Open or short in IGF or IGT6 circuit from igniter to engine ECU  Igniter

 

 Engine ECU  Open or short in crankshaft position sensor circuit

 Crankshaft position sensor  Crankshaft timing pulley

– 

 Engine ECU  Mechanical system (Jumping teeth of timing belt, belt

stretched)

 

 Engine ECU  Valve timing

 OCV  VVT controller assembly

 

 Engine ECU  Open or short in VVT sensor (camshaft position Sensor) circuit

 VVT sensor (camshaft position Sensor)

 

 Engine ECU

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

DI–17

P1351

(DI–102)

P1354

(DI–103)

P1520

(DI–111)

P1600

(DI–113)

P1645

(DI–115)

P1651

(DI–116)

P1656

(DI–120)

P1663

(DI–120)

P1666

(DI–116)

P1780

(DI–123)

VVT Sensor/Camshaft position Sensor Circuit Range/Performance Problem (Bank 2)

VVT System Malfunction (Bank

Stop Light Switch Signal Malfunction

Engine ECU BATT Malfunction

Body ECU Malfunction

VSV for ACIS Circuit Malfunction (European spec.)

OCV Circuit Malfunction (Bank

1) OCV Circuit Malfunction (Bank

VSV for AICS circuit Malfunction

Park/Neutral Position Switch Malfunction

 Same as DTC No. P1346  

 Same as DTC No. P1349  

 Short in stop light switch signal circuit  Stop light switch  Engine ECU

 Open in back up power source circuit  Engine ECU

 Body ECU  A/C ECU  Communication bus

 Open or short in VSV circuit for ACIS  VSV for ACIS  Engine ECU

 Open or short in OCV circuit  OCV  Engine ECM

 Open or short in VSV circuit  VSV  Engine ECM

 Short in park/neutral position switch circuit  Park/neutral position switch  Engine ECM

 

– 

 

*1: – Check engine warning light does not light up.  Check engine warning light lights up. *2: Europe only

LEXUS RX300 (RM785E)

DI–18

PARTS LOCATION

–DIAGNOSTICS ENGINE

DI68L–13

VSV for EVAP

VSV for No.2 ACIS

VSV for No.1 ACIS

Water Tempurature Sensor

Injector

Crankshaft Position Sensor

Ignition Coil with igniter

OCV (Bank 2)

VVT Senser (Bank 2)

A/F Sensor (Bank 2 Sensor 1)

OCV (Bank 1)

Knock Sensor 2

A/F Sensor (Bank 1 Sensor 1)

Engine ECU

Park/Neutral Position Switch

VVT Senser (Bank 2)

Oxygen Sensor (Bank 1 Sensor 2)

Knock Sensor 1

Combination Meter (Speedometer)

Throttle Position Sensor

DLC3

Charcoal Canister

IAC Valve

LEXUS RX300 (RM785E)

Fuel Pump

A14469

TERMINALS OF ECU

Pulse generation

96)

E7 E6 E5 E9 E8

DI–19

–DIAGNOSTICS ENGINE

DI7O6–02

192021

31 30 29 28 27

Symbols (Terminal No.)

123456789

1112

1314

2223242526

1234567

8910111213141516

2021222324

Wiring Color Condition STD Voltage (V)

123456

79101112

1314151617

123456789

1012 1113141516171819

202123 222426 25

BATT (E9–1) – E1 (E7–17) B–Y ↔ BR Always 9 – 14 +B (E9–16) – E1 (E7–17) B–R ↔ BR IG switch ON 9 – 14 VC (E7–2) – E2 (E7–18) Y–B ↔ BR IG switch ON 4.5 – 5.5

VTA1 (E7–23) – E2 (E7– 18) L–W↔ BR

IG switch ON, Throttle valve fully closed 0.3 – 1.0

IG switch ON, Throttle valve fully open 2.7 – 5.2 VG (E7–10) – E2G (E7–19) Y–R ↔ G–B Idling, A/C switch OFF 1.1 – 1.5 THA (E7–22) – E2 (E7–18) L–B ↔ BR Idling, Intake air temp. 20°C (68°F) 0.5 – 3.4 THW (E7–14) – E2 (E7–18) G–W ↔ BR Idling, Engine coolant temp. 80°C (176°F) 0.2 – 1.0 STA (E9–7) – E1 (E7–17) B ↔ BR Cranking 6.0 or more

IG switch ON 9 – 14 #10 (E7–5) – E01 (E8–21) W ↔ W–B

Idling

IG switch ON 9 – 14 #20 (E7–6) – E01 (E8–21) Y ↔ W–B

Idling

IG switch ON 9 – 14 #30 (E8–1) – E01 (E8–21) B ↔ W–B

Idling

IG switch ON 9 – 14 #40 (E8–2) – E01 (E8–21) L ↔ W–B

Idling

IG switch ON 9 – 14 #50 (E8–3) – E01 (E8–21) R ↔ W–B

Idling

IG switch ON 9 – 14 #60 (E8–4) – E01 (E8–21) G ↔ W–B

OC1+(E8–6) – OC1– (E8–5) Y–B ↔ G–W OC2+(E8–29) – OC2–(E8–18) G–R ↔ G–Y

Idling

IG switch ON

IGT1 (E8–1 1) – E1 (E7–17) B–Y ↔ BR IGT2 (E8–12) – E1 (E7–17) L–R ↔ BR IGT3 (E8–13) – E1 (E7–17) Y–G ↔ BR IGT4 (E8–14) – E1 (E7–17) L–Y ↔ BR Idling IGT5 (E8–15) – E1 (E7–17) Y ↔ BR IGT6 (E8–16) – E1 (E7–17) G–B ↔ BR VV2 (E8–22) – E1 (E7–17) L ↔ BR

LEXUS RX300 (RM785E)

1234567

89101112131415

16171819202122

A02016

Pulse generation

(See page DI–57)

Pulse generation

(See page DI–57)

Pulse generation

(See page DI–57)

Pulse generation

(See page DI–57)

Pulse generation

(See page DI–57)

Pulse generation

(See page DI–57)

Pulse generation

(See page DI–127)

Pulse generation

ee page DI–

DI–20

Pulse generation

–DIAGNOSTICS ENGINE

IG switch ON 4.5 – 5.5 IGF (E8–25) – E1 (E7–17) B ↔ BR

VV1+ (E8–10)

– NE– (E8–24)

NE+ (E8–16) – NE– (E8–24) B ↔ W Idling

ACIS (E8–17) – E01 (E8–21) R–Y ↔ W–B ACI1 (E7–15) – E01 (E8–21) LG ↔ W–B

FC (E9–3) – E01 (E8–21) L–Y ↔ W–B

EVP1 (E7–7) – E01 (E8–21) W–L ↔ W–B IG switch ON 9 – 14 RSO (E8–26) – E01 (E8–21) Y–R ↔ W–B IG switch ON, Disconnect E17 connector from engine ECU 9 – 14

OXS (E10–8) – E1 (E7–17) W ↔ BR Maintain engine speed at 2,500 rpm for 3 min. after warming up

HTS (E10–9) – E03 (E8–30) B ↔ W–B

KNKR (E8–27) – E1 (E7–17) W ↔ BR KNKL (E8–28) – E1 (E7–17) B ↔ BR

NSW (E10–20) – E1 (E7–17) B–W ↔ BR

SPD (E10–22) – E1 (E7–17) V–W ↔ BR IG switch ON,.Rotate driving wheel slowly 0 – 5 TC (E10–5) – E1 (E7–17) P–B ↔ BR IG switch ON 9 –14 W (E9–6) – E01 (E8–21) Y–G ↔ W–B IG switch ON Below 3.0 PS (E7–9) – E1 (E7–17) B–Y ↔ BR IG switch ON 9 – 14

CF (E10–26) – E1 (E7–17) R–W ↔ BR

TACH (E10–27) – E1 (E7–17) O ↔ BR Idling Pulse generation SIL (E9–4) – E1 (E7–17) W ↔ BR During transmission Pulse generation

STP (E9–15) – E1 (E7–17) G–O ↔ BR

AFR+ (E7–1 1)– E1 (E7–17) R ↔ BR AFL+ (E7–12) – E1 (E7–17) L ↔ BR AFR– (E7–20) – E1 (E7–17) G ↔ BR AFL– (E7–21)– E1 (E7–17) B–W ↔ BR

HAFR (E7–3) – E04 (E7–1) L ↔ W–B

HAFL (E7–4) – E05 (E7–8) G ↔ W–B

KSW (E10–23) – E1 (E7–17) L ↔ BR

RXCK (E10–19) – E1 (E7–17) P ↔ BR At time of inserting the key Pulse generation CODE (E10–28) – E1 (E7–17) V ↔ BR At time of inserting the key Pulse generation IGSW (E9–2) – E1 (E7–17) B–O ↔ BR IG switch ON 9 – 14 TXCT (E10–18) – E1 (E7–17) GR ↔ BR At time of inserting the key Pulse IMLO (E9–22) – E1 (E7–17) L ↔ BR In condition without the key inserted Pulse MREL (E9–8) – E1 (E7–17) B–W ↔ BR IG switch ON 9 – 14

LEXUS RX300 (RM785E)

O ↔ W Idling

Idling

IG switch ON 9 – 14

Idling 0 – 3.0

Idling 9 – 14

IG switch ON Below 3.0

Idling

IG switch ON, Other shift position in P , N 9 – 14

IG switch ON, Shift position in P , N 0 – 3.0

Electric cooling fan is operating on high speed 9 – 14

Electric cooling fan is operating on low speed or OFF 0– 2

IG switch ON, Brake pedal depressed 7.5 – 14

IG switch ON, Brake pedal released Below 1.5

IG switch ON 3.3

IG switch ON 3.0

IG switch ON Below 3.0

Idling (warm up engine) Pulse generation

IG switch ON Below 3.0

Idling (warm up engine) Pulse generation

At time of inserting the key Below 1.5

In condition without the key inserted 4 – 5

Pulse generation

(See page DI–96)

Pulse generation

(See page DI–67)

Pulse generation

(See page DI–67)

Pulse generation

(See page DI–71)

Pulse generation

(See page DI–63)

PROBLEM SYMPTOMS TABLE

DI–21

–DIAGNOSTICS ENGINE

DI1IA–24

Symptom

1. Starter and starter relay

Engine does not crank (Does not start)

2. Neutral start switch circuit

1. Engine immobiliser system

No initial combustion (Does not start)

No complete combustion (Does not start) 1. Fuel pump control circuit DI–128

Under normal condition (Difficult to start)

Cold engine (Difficult to start) 1. Fuel pump control circuit DI–128 Hot engine (Difficult to start) 1. Fuel pump control circuit DI–128

High engine idle speed (Poor idling)

Low engine idle speed (Poor idling)

Rough idling (Poor idling)

Hunting (Poor idling)

Hesitation/Poor acceleration (Poor driveability) 1. Fuel pump control circuit DI–128 Surging (Poor driveability) 1. Fuel pump control circuit DI–128

Soon after starting (Engine stall)

During A/C operation (Engine stall)

2. ECU power source circuit

3. Fuel pump control circuit

1. Fuel pump control circuit

2. Compression

1. A/C signal circuit (Compressor circuit)

2. ECU power source circuit

1. A/C signal circuit (Compressor circuit)

2. Fuel pump control circuit

1. Compression

2. Fuel pump control circuit

1. ECU power source circuit

2. Fuel pump control circuit

1. Engine immobiliser system

2. Fuel pump control circuit

1. A/C signal circuit (Compressor circuit)

2. Engine ECU

Suspect Area See page

ST–2

ST–20

DI–140

BE–2 DI–124 DI–128

DI–128

EM–3

–

DI–124

–

DI–128

EM–3

DI–128 DI–124

DI–128

BE–2

DI–128

–

IN–22

LEXUS RX300 (RM785E)

DI–22

–DIAGNOSTICS ENGINE

DI7O7–02

CIRCUIT INSPECTION

DTC P0100 Mass Air Flow Circuit Malfunction

CIRCUIT DESCRIPTION

The air flow meter uses a platinum hot wire. The hot wire air flow meter consists of a platinum hot wire, temparature sensor and a control circuit installed in a plastic housing. The hot wire air flow meter works on the principle that the hot wire and temparature sensor located in the intake air bypass of the housing detect any changes in the intake air temperature. The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This current flow is then measured as the output voltage of the air flow meter. The circuit is constructed so that the platinum hot wire and temparature sensor provide a bridge circuit, with the power transistor controlled so that the potential of A and B remains equal to maintain the set temperature.

Temparature

B+

sensor

Power Transistor

Platinum Hot Wire

Output Voltage

Temparature sensor

Platinum Hot Wire

FI6929 A09074 A09707

DTC No.

P0100

Open or short in air flow meter circuit with more than 3 sec. engine speed less than 4,000 rpm

DTC Detecting Condition Trouble Area

 Open or short in air flow meter circuit  Air flow meter  Engine ECU

HINT: After confirming DTC P0100 use the hand–held tester to confirm the air flow ratio from CURRENT DATA.

Air Flow Value (gm/sec.) Malfunction

Approx. 0.0

271.0 or more EVG circuit open

 Air flow meter power source circuit open  VG circuit open or short

LEXUS RX300 (RM785E)

WIRING DIAGRAM

DI–23

–DIAGNOSTICS ENGINE

W–B

J2 J/C

A10

Air Flow Meter

B–R

Engine Room J/B

EFI Relay

B–G

Battery

F11 FL Block

EFI

2I 5

B–W

Y–B

G–B

Engine ECU

E2G

MREL

A14512

INSPECTION PROCEDURE

HINT : Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Connect hand–held tester, and read value of air flow rate.

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Turn the ignition switch ON and push the hand–held tester main switch ON. (c) Start the engine.

CHECK:

Read air flow rate on the hand–held tester.

RESULT:

Type I Type II

Air flow rata (gm/sec.) 0.0 271.0 or more

LEXUS RX300 (RM785E)

Type I Go to step 2.

Type II Go to step 5.

DI–24

–DIAGNOSTICS ENGINE

2 Check voltage of air flow meter power source.

PREPARATION:

(a) Disconnect the air flow meter connector. (b) Turn the ignition switch ON.

1 (+)

CHECK:

Measure voltage between terminal 1 of the air flow meter connector and body ground.

OK:

Voltage: 9 – 14 V

BE6653 P24310

A00099

NG Check for open in harness and connector be-

tween EFI main relay (Marking: EFI) and air flow meter (See page IN–32).

3 Check voltage between terminals VG of engine ECU connector and body ground.

PREPARATION:

(+)

(–)

A02017

(a) Remove the engine ECU with connector still connected

(See page FI–70).

(b) Start the engine.

CHECK:

Measure voltage between terminal VG of the engine ECU connector and body ground while engine is idling.

OK:

Voltage:

0.5 – 3.0 V (P or N position and A/C switch OFF)

OK Check and replace engine ECU

(See page IN–32).

4 Check for open and short in harness and connector between air flow meter and

engine ECU (See page IN–32).

NG Repair or replace harness or connector.

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

Replace air flow meter.

5 Check continuity between terminal E2G of engine ECU connector and body

ground.

PREPARATION:

E2G

A02018

Remove the engine ECU with connector still connected (See page FI–70).

CHECK:

Check continuity between terminal E2G of the engine ECU connector and body ground.

OK:

Continuity (1 Ω or less)

NG Check and replace engine ECU

(See page IN–32).

DI–25

6 Check for open in harness and connector between air flow meter and engine

ECU (See page IN–32).

NG Repair or replace harness or connector.

Replace air flow meter.

LEXUS RX300 (RM785E)

DI–26

P0101

Air flow meter

–DIAGNOSTICS ENGINE

DTC P0101 Mass Air Flow Circuit Range/Performance

Problem

CIRCUIT DESCRIPTION

Refer to DTC P0100 on page DI–22.

DI7O8–02

DTC No.

P0101

After engine is warmed up, conditions (1), (2) and (3) continue with more than 10 sec. engine speed 1,500 rpm or less: (2 trip detection logic)

1. Throttle valve fully closed

2. Air flow meter output u 2.2 V

3. THW u 70 °C (158 °F) Conditions (1) and (2) continue with more than 10 sec.

engine speed 2,100 rpm or more: (2 trip detection logic)

1. VTA y 0.63 V

2. Air flow meter output t 1.06 V

DTC Detecting Condition Trouble Area

 Air flow meter

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Are there any other codes (besides DTC P0101) being output?

NO Replace air flow meter.

YES

Go to relevant DTC chart (See page DI–14).

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

DTC P0110 Intake Air Temp. Circuit Malfunction

CIRCUIT DESCRIPTION

The intake air temp. sensor is built into the air flow meter and

(fig. 1)

30 20

3 2

0.5

0.3

Resistance kΩ

0.2

0.1

– 20 0 20 40 60 80 100 (– 4) 32 68 104 140 176 212

Temp. °C (°F)

Acceptable

FI4741

senses the intake air temperature. A thermistor built in the sensor changes the resistance value according to the intake air temperature. The lower the intake air temperature, the greater the thermistor resistance value, and the higher the intake air temperature, the lower the thermistor resistance value (See fig. 1). The intake air temp. sensor is connected to the engine ECU (See below ). The 5 V power source voltage in the engine ECU is applied to the intake air temp. sensor from the terminal THA (THAR) via resistor R. That is, the resistor R and the intake air temp. sensor are connected in series. When the resistance value of the intake air temp. sensor changes in accordance with changes in the intake air temperature, the potential at terminal THA (THAR) also changes. Based on this signal, the engine ECU increases the fuel injection volume to improve driveability during cold engine operation.

DI–27

DI7O9–02

DTC No.

P0110 Open or short in intake air temp. sensor circuit

DTC Detecting Condition Trouble Area

 Open or short in intake air temp. sensor circuit  Intake air temp. sensor (inside air flow meter)  Engine ECU

HINT: After confirming DTC P0110 use the hand–held tester to confirm the intake air temperature from CURRENT DATA.

T emperature Displayed

–40°C (–40°F) Open circuit

140°C ( 284°F ) or more Short circuit

Malfunction

LEXUS RX300 (RM785E)

DI–28

WIRING DIAGRAM

–DIAGNOSTICS ENGINE

A10

Intake Air Temp. Sensor (Inside air flow meter)

L–B

THA

Engine ECU

5 V

A00328

INSPECTION PROCEDURE

HINT :

 If DTC P0110, P0115, P0120 are output simultaneously, E2 (Sensor Ground) may be open.  Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions

when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Connect hand–held tester, and read value of intake air temperature.

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Turn the ignition switch ON and push the hand–held tester main switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

Same as actual intake air temperature

HINT:

 If there is open circuit, hand–held tester indicates –40°C (–40 °F).  If there is short circuit, hand–held tester indicates 140°C (284°F) or more.

NG –40°C (–40°F )...Go to step 2

140°C (284°F) or more...Go to step 4.

Check for intermittent problems (See page DI–3).

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

2 Check for open in harness or engine ECU.

DI–29

PREPARATION:

(a) Disconnect the air flow meter connector.

Intake Air Temp. Sensor

Connecting

Engine ECU

(b) Connect the sensor wire harness terminals together. (c) Turn the ignition switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

Temperature value: 140°C (284°F) or more

BE6653

A00347

A00348

OK Confirm good connection at sensor. If OK, re-

3 Check for open in harness or engine ECU.

Intake Air Temp. Sensor

THA

Engine ECU

5 V

A02019

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70).

(b) Connect between terminals THA and E2 of the engine

ECU connector. HINT: Air flow meter connector is disconnected. Before checking, do a visual and contact pressure check for the engine ECU connector (See page IN–32).

CHECK:

Read temperature value on the hand–held tester.

OK:

Temperature value: 140°C (284°F) or more

OK Open in harness between terminals E2 or THA,

place air flow meter.

repair or replace harness.

Confirm good connection at engine ECU. If OK, check and replace engine ECU. (See page IN–32)

LEXUS RX300 (RM785E)

DI–30

4 Check for short in harness and engine ECU.

–DIAGNOSTICS ENGINE

PREPARATION:

(a) Disconnect the air flow meter connector.

Intake Air Temp. Sensor

Engine ECU

(b) Turn the ignition switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

BE6653 A00362 A00363

Temperature value: –40°C (–40°F)

OK Replace air flow meter.

5 Check for short in harness or engine ECU.

Intake Air Temp. Sensor

Engine ECU

5 V

THA

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70). (b) Disconnect the E6 connector of the engine ECU. HINT: Air flow meter connector is disconnected. (c) Turn the ignition switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

Temperature value: –40°C (–40°F)

E6 Connector

A02043

Check and replace engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

OK Repair or replace harness or connector.

DI–31

–DIAGNOSTICS ENGINE

DI7OA–02

DTC P0115 Water Temp. Circuit Malfunction

CIRCUIT DESCRIPTION

A thermistor built into the water temp. sensor changes the resistance value according to the water temperature. The structure of the sensor and connection to the engine ECU is the same as in the DTC P0110 shown on page DI–27.

DTC No.

P0115 Open or short in water temp. sensor circuit

DTC Detecting Condition Trouble Area

 Open or short in water temp. sensor circuit  Water temp. sensor  Engine ECU

HINT: After confirming DTC P0115 use the hand–held tester to confirm the water temperature from CURRENT DATA.

T emperature Displayed

–40°C (–40°F) Open circuit

140C° (284°F) or more Short circuit

Malfunction

WIRING DIAGRAM

E2 Water Temp. Sensor

G–W

Engine ECU

THW

5 V

LEXUS RX300 (RM785E)

A00328

DI–32

–DIAGNOSTICS ENGINE

INSPECTION PROCEDURE

HINT:

 If DTC P0110, P0115, P0120 are output simultaneously, E2 (Sensor Ground) may be open.  Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions

1 Connect hand–held tester, and read value of water temperature.

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Turn the ignition switch ON and switch the hand–held tester main switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

Same as actual water temperature

HINT:

 If there is open circuit, Hand–held tester indicates –40°C (–40°F).  If there is short circuit, Hand–held tester indicates 140°C (284°F) or more.

NG –40°C (–40°F)...Go to step 2.

Check for intermittent problems (See page DI–3).

140°C (284°F) or more...Go to step 4.

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

2 Check for open in harness or engine ECU.

DI–33

PREPARATION:

(a) Disconnect the water temp. sensor connector.

Water Temp. Sensor

Engine ECU

(b) Connect sensor wire harness terminals together. (c) Turn the ignition switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

Temperature value: 140°C (284°F) or more

BE6653

A00365

Connecting

A00366

OK Confirm good connection at sensor. If OK, re-

3 Check for open in harness or engine ECU.

Water Temp. Sensor

THW

Engine ECU

5 V

THW

A02020

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70). (b) Connect between terminals THW, and E2 of the engine

ECU connector. HINT: Water temp. sensor connector is disconnected. Before checking, do a visual and contact pressure check for the engine ECU connector (See page IN–32). (c) Turn the ignition switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

Temperature value: 140°C (284°F) or more

place water temp. sensor.

Confirm good connection at engine ECU. If OK, check and replace engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

OK Open in harness between terminals E2 or THW,

repair or replace harness.

DI–34

4 Check for short in harness and engine ECU.

–DIAGNOSTICS ENGINE

PREPARATION:

(a) Disconnect the water temp. sensor connector.

Water Temp. Sensor

Engine ECU

(b) Turn the ignition switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

BE6653 A00372 A00373

Temperature value: –40°C (–40°F)

OK Replace water temp. sensor.

5 Check for short in harness or engine ECU.

Water Temp. Sensor

Engine ECU

5 V

THW

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70). (b) Disconnect the E6 connector of the engine ECU. HINT: Water temp. sensor connector is disconnected. (c) Turn the ignition switch ON.

CHECK:

Read temperature value on the hand–held tester.

OK:

Temperature value: –40°C (–40°F)

E6 Connector

A02043

Check and replace engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

OK Repair or replace harness or connector.

–DIAGNOSTICS ENGINE

DTC P0116 Water Temp. Circuit Range/Performance

Problem

CIRCUIT DESCRIPTION

Refer to DTC P0115 on page DI-31.

DI–35

DI6UZ–04

DTC No.

P0116

If THW < –6.7°C (20°F), 20 min. or more after starting engine, engine coolant temp. sensor value is 35°C (95°F) or less (2 trip detection logic)

If THW y –6.7°C (20°F) and < 10°C (50°F), 5 min. or more after starting engine, engine coolant temp. sensor value is 35°C (95°F) or less (2 trip detection logic)

If THW y 10°C (50°F), 2 min. or more after starting engine, engine coolant temp. sensor value is 35°C (95°F) or less (2 trip detection logic)

DTC Detecting Condition Trouble Area

 Engine coolant temp. sensor  Cooling system

INSPECTION PROCEDURE

HINT:

 If DTC P0115 and P01 16 are output simultaneously, water temp. sensor circuit may be open. Perform

troubleshooting of DTC P0115 first.

 Read freeze frame data using hand–held tester or OBD scan tool. Because freeze frame records the

engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Are there any other codes (besides DTC P0116) being output?

2 Check thermostat (See page CO–10).

Replace engine coolant temp. sensor.

LEXUS RX300 (RM785E)

YES Go to relevant DTC chart.

NG Replace thermostat.

DI–36

Trouble Area

–DIAGNOSTICS ENGINE

DTC P0120 Throttle Position Sensor Circuit Malfunction

CIRCUIT DESCRIPTION

Throttle Position Sensor

Engine ECU

VTA

P24296

The throttle position sensor is mounted in the throttle body and detects the throttle valve opening angle. When the throttle valve is fully closed, a voltage of approx. 0.7 V is applied to terminal VTA of the engine ECU. The voltage applied to the terminals VTA of the engine ECU increases in proportion to the opening angle of the throttle valve and becomes approx. 2.7 – 5.2 when the throttle valve is fully opened. The engine ECU judges the vehicle driving conditions from these signals input from terminals VTA and uses them as one of the conditions for deciding the air–fuel ratio correction, power increase correction and fuel–cut control etc.

DI84A–01

DTC No.

P0120

Condition (a) or (b) continues: (a) VTA < 0.1 V (b) VTA > 4.9 V

DTC Detecting Condition Trouble Area

 Open or short in throttle position sensor circuit  Throttle position sensor  Engine ECU

HINT: After confirming DTC P0120, use the hand–held tester to confirm the throttle valve opening percentage and closed throttle position switch condition.

Throttle valve opening position

expressed as percentage

Throttle valve fully closed Throttle valve fully open

0 % 0%

Approx. 100% Approx. 100% E2 line open

Trouble Area

VC line open

VTA line open or short

LEXUS RX300 (RM785E)

WIRING DIAGRAM

T11

Throttle Position Sensor

DI–37

–DIAGNOSTICS ENGINE

Engine ECU

5 V

S05019

2BR

Y–B

L–W

23 E7

VTA1

INSPECTION PROCEDURE

HINT :

 If DTCs P0110, P0115 and P0120 are output simultaneously, E2 (sensor ground) may be open.  Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions

when the malfunction is detected. When troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. at the time of the malfunction.

When using hand–held tester:

1 Connect hand–held tester, read throttle valve opening percentage.

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Turn the ignition switch ON and push the hand–held tes-

ter main switch ON.

CHECK:

Read the throttle valve opening percentage.

OK:

Throttle valve opening position ex-

LEXUS RX300 (RM785E)

FI7052

Throttle valve

Fully open Approx. 75 %

Fully closed Approx. 10 %

pressed as percentage

DI–38

–DIAGNOSTICS ENGINE

OK Check for intermittent problems (See page

DI–3).

2 Check voltage between terminal 1 of wire harness side connector and body

ground.

1 (+)

A00437

3 Check throttle position sensor.

1 2 3

S05339

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70).

(b) Turn the ignition switch ON.

CHECK:

Measure voltage between terminal 1 (VC) of wire harness side connector and body ground.

OK:

Voltage: 4.5 – 5.5 V

NG Go to step 5.

PREPARATION:

Disconnect the throttle position sensor connector.

CHECK:

Measure voltage between terminals 1, 3 and 2 of throttle position sensor.

OK:

Terminals Throttle valve Resistance

1 – 2 – 2.5 – 5.9 kΩ 3 – 2 Fully closed 0.2 – 6.3 kΩ 3 – 2 Fully open 2.0 – 10.2 kΩ

LEXUS RX300 (RM785E)

OK Replace throttle position sensor.

–DIAGNOSTICS ENGINE

4 Check voltage between terminals VTA1 and E2 of engine ECU.

DI–39

PREPARATION:

(a) Remove the engine ECU with connector still connected

VTA1 (+)

E2 (–)

(See page FI–70).

(b) Turn the ignition switch ON.

CHECK:

Measure voltage between terminals VTA1 and E2 of the engine ECU connector.

OK:

A02021

Throttle valve Voltage

Fully closed 0.3 – 1.0 V

Fully open 2.7 – 5.2 V

NG Check and replace engine ECU (See page

IN–32).

Check for open and short circuit in harness and connector between engine ECU and throttle position sensor (VTA line) (See page IN–32).

5 Check voltage between terminals VC and E2 of engine ECU.

VC (+)

E2 (–)

A02022

Check for open in harness and connector between engine ECU and sensor (VC line) (See page IN–32).

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70).

(b) Turn the ignition switch ON.

CHECK:

Measure voltage between terminals VC and E2 of the engine ECU connector.

OK:

Voltage: 4.5 – 5.5 V

NG Check and replace engine ECU (See page

IN–32).

LEXUS RX300 (RM785E)

DI–40

–DIAGNOSTICS ENGINE

When not using hand–held tester:

1 Check voltage between terminals VTA1 and E2 of engine ECU

PREPARATION:

(a) Remove the engine ECU with connector still connected

VTA1 (+)

E2 (–)

(See page FI–70).

(b) Turn the ignition switch ON.

CHECK:

Measure voltage between terminals VTA1 and E2 of the engine ECU connector.

OK:

A02021

Throttle valve Voltage

Fully closed 0.3 – 1.0 V

Fully open 2.7 – 5.2 V

NG Check and replace engine ECU (See page

IN–32).

Check for open and short in harness and connector between engine ECU and throttle position sensor (VTA line) (See page IN–32).

2 Check voltage between terminals VC and E2 of engine ECU connector.

VC (+)

E2 (–)

A02022

Check for open in harness and connector between engine ECU and sensor (VC line) (See page IN–32).

LEXUS RX300 (RM785E)

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70).

(b) Turn the ignition switch ON.

CHECK:

Measure voltage between terminals VC and E2 of the engine ECU connector.

OK:

Voltage: 4.5 – 5.5 V

NG Check and replace engine ECU (See page

IN–32).

–DIAGNOSTICS ENGINE

DTC P0121 Throttle/Pedal Position Sensor/Switch ”A”

Circuit Range/Performance Problem

CIRCUIT DESCRIPTION

Refer to DTC P0120 on page DI-36.

DI–41

DI1LI–10

DTC No.

P0121

While vehicle speed drops from 30 km/h (19 mph) or more to 0

km/h (0 mph), output value of throttle position sensor is out of

applicable range. (2 trip detection logic)

DTC Detecting Condition Trouble Area

 Throttle position sensor  Engine ECU

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

Replace throttle body (See page FI–33).

LEXUS RX300 (RM785E)

DI–42

–DIAGNOSTICS ENGINE

DI7J3–03

DTC P0125 Insufficient Coolant Temp. for Closed Loop

Fuel Control

CIRCUIT DESCRIPTION

To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three–way catalytic converter is used. For the most efficient use of the three–way catalytic converter, the air–fuel ratio must be precisely controlled so that it is always close to the stoichiometric air–fuel ratio. The A/F sensor has the characteristic that provides output voltage* approximately proportional to the existing air–fuel ratio. The A/F sensor output voltage* is used to provide feedback for the engine ECU to control the air–fuel ratio. By the A/F sensor output, the engine ECU can determine the deviation amount from the stoichiometric air– fuel ratio and control the proper injection time immediately. If the A/F sensor is malfunctioning, the engine ECU is unable to perform accurate air–fuel ratio control. The A/F sensor is equipped with a heater which heats the zirconia element. The heater is controlled by the engine ECU. When the intake air volume is low (the temp. of the exhaust gas is low), current flows to the heater to heat the sensor for accurate oxygen concentration detection. *: The voltage value changes at the inside of the engine ECU only.

DTC No.

P0125

Atmosphere

Platinum

Electrode

Solid Electrolyte

(Zirconia Element)

Platinum

Electrode Heater

Coating (Ceramic)

Cover

After engine is warmed up, A/F sensor output* does not

change when conditions (a), (b) and (c) continue for at least

1.5 min.

*: Output value changes at inside of engine ECU only.

(a) Engine speed: 1,500 rpm or more

(b) Vehicle speed: 40 ∼ 100 km/h (25 ∼ 62 mph)

(d) After starting engine y 140 sec

Exhaust Gas

DTC Detecting Condition Trouble Area

(V)

4.0

3.8

3.6

3.4

3.2

3.0

2.8

2.6

engine ECU

Monitored

A/F Sensor Voltage

2.4 17

161512 1413 1918

Air–Fuel Ratio

 Fuel system  Injector  Ignition system  Gas leakage on exhaust system  Open or short in A/F sensor circuit (bank 1, 2 sensor 1)  A/F sensors (bank 1, 2 sensor 1)  Engine ECU

A00477

LEXUS RX300 (RM785E)

DI–43

–DIAGNOSTICS ENGINE

HINT:

 After confirming DTC P0125, use a hand-held tester to confirm voltage output of heated oxygen senĆ

sors (bank 1, 2 sensor 1) from CURRENT DATA.

 The engine ECU controls the voltage of AFL+, AFR+ and AFL–, AFR– terminals of engine ECU to the

fixed voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without a hand–held tester.

WIRING DIAGRAM

Engine ECU

MRELE9

E10

HTS

OXS

E10

HAFR

AFR+

AFR–

HAFL

E7 12

AFL+

AFL–

B–W

F11 FL Block

Engine Room J/B

EFI Relay 1

EFI

R/B No. 2

A/F HEATER Relay

A/F HTR

Battery

B–W

W–B

B–R

A J4

H12 Oxygen Sensor (Bank 1 Sensor 2)

J/C

B–R BR

W–B

IA2

2 4

IA2

A11 A/F Sensor

B–R

EB1

(Bank 1 Sensor 1) B–R

B–R

3 4

EB1

IA2

A12 A/F Sensor

(Bank 2 Sensor 1)

B–R

8IH1

J2 J/C

BR–W

B–W

J10

J/C

LEXUS RX300 (RM785E)

A14513

DI–44

–DIAGNOSTICS ENGINE

INSPECTION PROCEDURE

HINT: Read freeze frame data using a hand–held tester . Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Are there any other codes (besides DTC P0125) being output ?

YES Go to relevant DTC chart.

2 Connect hand–held tester and read value for voltage output of A/F sensors

(bank 1, 2 sensor 1).

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Warm up the A/F sensors (bank 1, 2 sensor 1) with the engine at 2,500 rpm for approx. 90 sec.

CHECK:

Read voltage value of A/F sensors (bank 1, 2 sensor 1) on the screen of hand–held tester when you perform all the following conditions. HINT: The voltage of AFL+, AFR+ terminal of the engine ECU is fixed to 3.3 V and the AFL–, AFR– terminal to 3.0 V. Therefore, it is impossible to check the A/F sensor output voltage at the terminals (AFL+, AFR+/AFL–, AFR–) of the engine ECU.

OK:

Condition A/F Sensor V oltage value Engine idling Engine idling  Not remains at 3.3. V Driving at engine speed 1,500 rpm or more and vehicle

speed 40 km/h (25 mph) or more, and operate throttle valve open and close

 Not remains at 3.8 V or more  Not remains at 2.8 V or less

HINT:

 During fuel enrichment, there is a case that the output voltage of A/F sensors (bank 1, 2 sensor 1) is

below 2.8 V,itisnormal.

 During fuel cut, there is a case that the output voltage of A/F sensors (bank 1, 2 sensor 1) is above

3.8 V, it is normal.

 If output voltage of A/F sensors (bank 1, 2 sensor 1) remains at 3.30 V even after performing all the

above conditions, A/F sensors (bank 1, 2 sensor 1) circuit may be open.

 If output voltage of A/F sensor remains at 3.8 V or more, or 2.8 V or less even after performing all the

above conditions, A/F sensors (bank 1, 2 sensor 1) circuit may be short.

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

OK Go to step 9.

3 Check for open and short in harness and connector between engine ECU and

A/F sensors (bank1, 2 sensor1) (See page IN–32).

NG Repair or replace harness or connector.

4 Check resistance of A/F sensor heaters (bank1, 2 sensor1) (See page FI–67).

DI–45

NG Replace A/F sensor.

5 Check air induction system (See page FI–1).

NG Repair or replace.

6 Check fuel pressure (See page FI–5).

NG Check and repair fuel pump, fuel pipe line and

filter (See page FI–1).

LEXUS RX300 (RM785E)

DI–46

7 Check injector injection (See page FI–18).

NG Replace injector.

8 Check gas leakage on exhaust system.

NG Repair or replace

–DIAGNOSTICS ENGINE

Replace A/F sensors (bank1, 2 sensor1).

9 Perform confirmation driving pattern (See page DI–85).

10 Is there DTC P0125 being output again ?

YES Check and replace engine ECU

(See page IN–32).

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

11 Did vehicle run out of fuel in the past ?

NO Check for intermittent problems

YES

DTC P0125 is caused by running out of fuel.

DI–47

(See page DI–3).

LEXUS RX300 (RM785E)

DI–48

–DIAGNOSTICS ENGINE

DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1

Sensor 2)

CIRCUIT DESCRIPTION

Refer to DTC P0125 on page DI–42.

DI68O–11

DTC No.

P0136

Voltage output of heated oxygen sensor remains at 0.45 V or more or 0.55 V or less when vehicle is driven at 100 km/h (62 mph) or more after engine is warmed up (2 trip detection logic)

DTC Detecting Condition Trouble Area

 Open or short in heated oxygen sensor circuit  Oxygen sensor

HINT:

Sensor 2 refers to the sensor farther away from the engine body.

WIRING DIAGRAM

Refer to DTC P0125 on page DI–42.

CONFIRMATION DRIVING PATTERN

Vehicle speed

30 km/h (19 mph)

IG SW OFF

Once 40 sec. or more

(d)

Idling(c)

(e)

Twice 40 sec. or more

(f)

(e)

Nine times 40 sec. or more

(f)

(e)

(a)

(b)

60 sec. or more

10 sec. 10 sec.

10 sec.

A09300

(a) Connect the hand–held tester to the DLC3. (b) Switch the hand–held tester from the Normal Mode to the Check (Test) Mode

(See page DI–3). (c) Start the engine and let the engine idle for 60 seconds or more. (d) Drive the vehicle at 30 km/h (19 mph) or more for 40 seconds or more. (e) Let the engine idle for 10 seconds or more. (f) Preform steps (d) to (e) 9 times. HINT: If a malfunction exists, the CHK ENG warning light will be indicated on the multi information display during step (f).

NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction will not be possible. If you do not have a hand–held tester, turn the ignition switch OFF after performing steps (c) to (f), then perform steps (c) to (f) again.

LEXUS RX300 (RM785E)

DI–49

–DIAGNOSTICS ENGINE

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Are there any other codes (besides DTC P0136) being output?

YES Go to relevant DTC chart (See page DI–14).

2 Check for open and short in harness and connector between engine ECU and

oxygen sensor (See page IN–32).

NG Repair or replace harness or connector.

3 Check output voltage of oxygen sensor.

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Warm up the engine to normal operating temperature.

CHECK:

Read voltage output of the oxygen sensor when the engine suddenly raced. HINT: Perform quick racing to 4,000 rpm 3 min. using the accelerator pedal.

OK:

Oxygen sensor output voltage: Alternates from 0.4 V or less to 0.5 V or more.

OK Check that each connector is properly con-

nected.

Replace oxygen sensor.

LEXUS RX300 (RM785E)

DI–50

–DIAGNOSTICS ENGINE

DTC P0141 Oxygen Sensor Heater Circuit

Malfunction (Bank 1 Sensor 2)

CIRCUIT DESCRIPTION

Refer to DTC P0125 on page DI–42.

DI2S8–15

DTC No.

When the heater operates, heater current exceeds 2 A

P0141

Heater current of 0.2 A or less when the heater operates

DTC Detecting Condition Trouble Area

 Open or short in heater circuit of oxygen sensor  Oxygen sensor heater  Engine ECU

WIRING DIAGRAM

Refer to DTC P0125 on page DI–42.

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Check voltage between terminals HT1A, HT1B of engine ECU connector and

body ground.

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70).

(b) Turn the ignition switch ON.

CHECK:

Measure voltage between terminals HTS of the engine ECU connector and body ground. HINT:

OK:

Voltage: 9 – 14 V

BE6653 A10221

HTS(+)

A11441

LEXUS RX300 (RM785E)

OK Check and replace engine ECU

(See page IN–32).

–DIAGNOSTICS ENGINE

2 Check resistance of oxygen sensor heater (See page FI–69).

NG Replace oxygen sensor.

Check and repair harness or connector between main relay and oxygen sensor and engine ECU (See page IN–32).

DI–51

LEXUS RX300 (RM785E)

DI–52

–DIAGNOSTICS ENGINE

DI84B–01

DTC P0171 System too Lean (Fuel Trim) (Bank 1)

DTC P0172 System too Rich (Fuel Trim) (Bank 1)

DTC P0174 System too Lean (Fuel Trim) (Bank 2)

DTC P0175 System too Rich (Fuel Trim) (Bank 2)

CIRCUIT DESCRIPTION

Fuel trim refers to the feedback compensation value compared against the basic injection time. Fuel trim includes short–term fuel trim and long–term fuel trim. Short–term fuel trim is the short–term fuel compensation used to maintain the air–fuel ratio at its ideal theoretical value. The signal from the A/F sensor is approximately proportional to the existing air–fuel ratio, and engine ECU comparing it with the ideal theoretical value, the engine ECU reduces fuel volume immediately if the air–fuel ratio is rich and increases fuel volume if it is lean. Long–term fuel trim compensates the deviation from the central value of the short–term fuel trim stored up by each engine tolerance, and the deviation from the central value due to the passage of time and changes of using environment. If both the short–term fuel trim and long–term fuel trim exceed a certain value, it is detected as a malfunction and the check engine warning light lights up.

DTC No.

P0171 P0174

P0172 P0175

DTC Detecting Condition Trouble Area

When air fuel ratio feedback is stable after engine warming up, fuel trim is considerably in error on RICH side (2 trip detection logic)

When air fuel ratio feedback is stable after engine warming up, fuel trim is considerably in error on LEAN side (2 trip detection logic)

 Gas leakage on exhaust system  Air intake (hose loose)  Fuel line pressure  Injector blockage  Mass air flow meter  Engine coolant temp. sensor  A/F sensors (bank 1, 2 sensor 1)

 Gas leakage on exhaust system  Fuel line pressure  Injector leak, blockage  Mass air flow meter  Engine coolant temp. sensor  A/F sensors (bank 1, 2 sensor 1)

LEXUS RX300 (RM785E)

DI–53

–DIAGNOSTICS ENGINE

HINT:

 When DTC P0171 or P0174 is recorded, the actual air–fuel ratio is on the lean side. When DTC P0172

or P0175 is recorded, the actual air–fuel ratio is on the rich side.

 If the vehicle runs out of fuel, the air–fuel ratio is lean and DTC P0171 or P0174 is recorded. The check

engine warning light then comes on.

 If the total of the short–term fuel trim value and long–term fuel trim value is within ± 35 % (80°C (176°F)

or more), the system is functioning normally.

 The A/F sensors (bank 1, 2 sensor 1) output voltage and the short–term fuel trim value can be read

using the hand–held tester.

 The engine ECU controls the voltage of AFL+, AFR+ and AFL–, AFR– terminals of the engine ECU

to the fixed voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without hand–

held tester.

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Check air induction system (See page FI–1).

NG Repair or replace.

2 Check injector injection (See page FI–18).

NG Replace injector.

3 Check air flow meter and water temp. sensor (See pages FI–30 and FI–63).

LEXUS RX300 (RM785E)

NG Repair or replace.

DI–54

–DIAGNOSTICS ENGINE

4 Check for spark and ignition (See page IG–1).

NG Repair or replace.

5 Check fuel pressure (See page FI–5).

NG Check and repair fuel pump, pressure regulator,

fuel pipe line and filter (See page FI–1).

6 Check gas leakage on exhaust system.

NG Repair or replace.

7 Check the output voltage A/F sensors (bank1, 2 sensor1).

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Warm up the A/F sensors (bank1, 2 sensor1) with the engine speed at 2,500 rpm for approx. 90 sec.

CHECK:

Read voltage value of A/F sensors (bank1, 2 sensor1) on the screen of the hand–held tester when you perform all the following conditions. HINT: The voltage of AFL+, AFR+ terminal of engine ECU is fixed to 3.3 V and AFL–, AFR– terminal to 3.0 V . Therefore, it is impossible to check the A/F sensors (bank1, 2 sensor1) output voltage at the terminals (AFL+, AFR+ / AFL–, AFR–) of the engine ECU.

LEXUS RX300 (RM785E)

DI–55

–DIAGNOSTICS ENGINE

OK:

Condition A/F Sensor Voltage value Engine idling Engine racing Driving at engine speed 1,500 rpm or more and vehicle

speed 40 km/h (25mph) or more, and operate throttle valve open and close

 Not remain at 3.30 V  Not remain at 3.8 V or more  Not remain at 2.8 V or less

HINT:

 During fuel enrichment, there is a case that the output voltage of A/F sensors (bank1, 2 sensor1) is

below 2.8 V, it is normal.

 During fuel cut, there is a case that the output voltage of A/F sensors (bank1, 2 sensor1) is above 3.8

V, it is normal.

 If the output voltage of A/F sensors (bank1, 2 sensor1) remains at 3.30 V even after performing all the

above conditions, A/F sensors (bank1, 2 sensor1) circuit may be open.

 If the output voltage of A/F sensors (bank1, 2 sensor1) remains at 3.8 V or more, or 2.8 V or less even

after performing all the above conditions, A/F sensors (bank1, 2 sensor1) circuit may be short.

OK Go to step 9.

8 Check for open and short in harness and connector between engine ECU and

A/F sensors (bank1, 2 sensor1) (See page IN–32).

NG Repair or replace harness or connector.

Replace A/F sensors (bank1, 2 sensor1).

9 Perform confirmation driving pattern (See page DI–85).

LEXUS RX300 (RM785E)

DI–56

–DIAGNOSTICS ENGINE

10 Is there DTC P0171, P0172, P0174 or P0175 being output again ?

YES Check and replace engine ECU

(See page IN–32).

11 Did vehicle run out of fuel in the past ?

NO Check for intermittent problems

(See page DI–3).

YES

DTC P0171, P0172, P0174 or P0175 is caused by running out of fuel.

LEXUS RX300 (RM785E)

DI–57

Valve timing

P0303

Air fl

P0304

For any articular 1,000 revolutions of engine, misfiring is de

Open or sho

0305

tected which causes a deterioration in emissions

 Oen or short in engine wire

P0306

–DIAGNOSTICS ENGINE

DTC P0300 Random/Multiple Cylinder Misfire Detected

DTC P0301 Cylinder 1 Misfire Detected

DTC P0302 Cylinder 2 Misfire Detected

DTC P0303 Cylinder 3 Misfire Detected

DTC P0304 Cylinder 4 Misfire Detected

DI12T–13

DTC P0305 Cylinder 5 Misfire Detected

DTC P0306 Cylinder 6 Misfire Detected

CIRCUIT DESCRIPTION

Misfire: The engine ECU uses the crankshaft position sensor and camshaft position sensor to monitor changes in the crankshaft rotation for each cylinder. The engine ECU counts the number of times the engine speed change rate indicates that misfire has occurred. And when the misfire rate equals or exceeds the count indicating that the engine condition has deteriorated, the check engine warning light lights up. If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the check engine warning light blinks when misfiring occurs.

DTC No.

P0300

P0301 P0302 P0303

P0305

Misfiring of random cylinders is detected during any particular 200 or 1,000 revolutions

For any particular 200 revolutions for engine, misfiring is detected which can cause catalyst overheating (This causes MIL to blink) (2 trip detection logic)

For any particular 1,000 revolutions of engine, misfiring is de-

(2 trip detection logic)

HINT: When the 2 or more codes for a misfiring cylinder are recorded repeatedly but no random misfire code is recorded, it indicates that the misfires were detected and recorded at different times.

LEXUS RX300 (RM785E)

DTC Detecting Condition Trouble Area

 Ignition system  Injector  Fuel pressure  Compression pressure  Valve clearance  Valve timin



ow meter

 Water temp. sensor

  Connector connection  Engine ECU

rt in engine wir

DI–58

WIRING DIAGRAM

–DIAGNOSTICS ENGINE

I15 Ignition Switch

AM2 IG2

W–R

F11 FL Block

Battery

Instrument Panel J/B

Engine Room J/B

(*1): LHD (*2): RHD

AM2

L–R

JH1

W–L (*1) W–R (*2)

L–R

I7 Injector No. 1

L–R

I8 Injector No. 2

L–R

I9 Injector No. 3

L–R

I10 Injector No. 4

L–R

I1 1 Injector No. 5

L–R

I12 Injector No. 6

L–R

Engine ECU

#10

#20

#30

#40

#50

#60

A14514

LEXUS RX300 (RM785E)

DI–59

–DIAGNOSTICS ENGINE

CONFIRMATION DRIVING PATTERN

(a) Connect the hand–held tester. (b) Record DTC and the freeze frame data. (c) Use the hand–held tester to set to Check Mode (See page DI–3). (d) Drive the vehicle several times with the engine speed, load and its surrounding range shown with EN-

GINE SPD, CALC LOAD in the freeze frame data or MISFIRE RPM, MISFIRE LOAD in the data list. If you have no hand–held tester, turn the ignition switch OFF after the symptom is simulated the first time. Then repeat the simulation process again. HINT: In order to memorize DTC of misfire, it is necessary to drive around MISFIRE RPM, MISFIRE LOAD in the data list for the following period of time.

Engine Speed

Idling 3 minutes 30 seconds or more 1000 rpm 3 minutes or more 2000 rpm 1 minutes 30 seconds or more 3000 rpm 1 minutes or more

Time

(e) Check whether there is misfire or not by monitoring DTC and the freeze frame data. After that, record

them.

(f) Turn ignition switch OFF and least 5 seconds.

INSPECTION PROCEDURE

HINT:

 If is the case that DTC besides misfire is memorized simultaneously , first perform the troubleshooting

for them.

 Read freeze frame data using hand–held tester. Because freeze frame data records the engine condi-

tions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

 When the vehicle is brought to the workshop and the misfire is not occurred, misfire can be confirmed

by reproducing the condition or freeze frame data. Also, after finishing the repair, confirm that there is no misfire. (See the confirmation driving pattern)

 When either of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data

is besides the range of ±20 %, there is a possibility that the air–fuel ratio is inclining either to RICH (–20 % or less) or LEAN (+20 % or more).

 When COOLANT TEMP in the freeze frame data is less than 80°C (176°F), there is a possibility or

misfire only during warning up.

 In the case that misfire cannot be reproduced, the reason may be because of the driving with lack or

fuel, the use of improper fuel, a stain of ignition plug, and etc.

LEXUS RX300 (RM785E)

DI–60

–DIAGNOSTICS ENGINE

1 Check wire harness, connector and vacuum hose in engine room.

CHECK:

(a) Check the connection conditions of wire harness and connector. (b) Check the disconnection, piping and break or vacuum hose.

NG Repair or replace, then confirm that there is no

misfire (See confirmation driving pattern).

2 Check spark plug and spark of misfiring cylinder.

PREPARATION:

Remove the spark plug (See page IG–1).

CHECK:

(a) Check the electrode of carbon deposits electrode. (b) Check the electrode gap.

OK:

(a) No large carbon deposit present. Not wet with gasoline or oil. (b) Electrode gap: 1.1 mm (0.043 in.)

PREPARATION:

(a) Install the spark plug to the ignition coil. (b) Disconnect the injector connector. (c) Ground the spark plug.

CHECK:

Check if spark occurs while the engine is being cracked.

NOTICE: To prevent excess fuel being injected from the injectors during this test, don’t crank the engine for more than 5 – 10 seconds at a time. OK:

Spark jumps across electrode gap.

B02101 B04941

1.1 mm

A06102

LEXUS RX300 (RM785E)

NG Replace or check ignition system (See page

IG–1).

–DIAGNOSTICS ENGINE

3 Check voltage of engine ECU terminals for injector of failed cylinder.

DI–61

PREPARATION:

(a) Remove the engine ECU with connector still connected

#20

#30#40

#10

(See page FI–70).

(b) Turn the ignition switch ON.

CHECK:

Measure voltage between applicable terminal of the engine

#60

#50

(+)

(–)

A02024

ECU connector and body ground.

OK:

Voltage: 9 – 14 V

Reference: INSPECTION USING OSCILLOSCOPE

With the engine idling, measure between terminals #10 – #40 and E01 of the engine ECU connector. HINT: The correct waveforms are as shown.

10 V/ Division

Injector Signal Waveform

10 V/ Division

(Magnification)

FI6588

GND

FI6538

100 msec./Division (Idling)

GND

Injection duration

OK Go to step 4.

1 msec./Division (Idling)

A00064

LEXUS RX300 (RM785E)

DI–62

–DIAGNOSTICS ENGINE

4 Check resistance of injector of misfiring cylinder (See page FI–18).

NG Replace injector.

Check for open and short in harness and connector between injector and engine ECU (See page IN–32).

5 Check fuel pressure (See page FI–5).

NG Check and repair fuel pump, pressure regulator,

fuel pipe line and filter (See page FI–1).

6 Check injector injection (See page FI–22).

NG Replace injector.

7 Check mass air flow meter and water temp. sensor (See pages FI–30 and

FI–63).

Check compression pressure, valve clearance and valve timing.

LEXUS RX300 (RM785E)

NG Repair or replace.

DI–63

–DIAGNOSTICS ENGINE

DI4EA–14

DTC P0325 Knock Sensor 1 Circuit Malfunction (Bank 1)

DTC P0330 Knock Sensor 2 Circuit Malfunction (bank 2)

CIRCUIT DESCRIPTION

Each of knock sensor is fitted to the right bank and left bank of the cylinder block to detect engine knocking. This sensor contains a piezoelectric element which generates a voltage when it becomes deformed, which occurs when the cylinder block vibrates due to knocking. If engine knocking occurs, ignition timing is retarded to suppress it.

DTC No.

P0325

P0330

No knock sensor 1 signal to engine ECU with engine speed between 2,000 rpm and 5,600 rpm

No knock sensor 2 signal to engine ECU with engine speed between 2,000 rpm and 5,600 rpm

DTC Detecting Condition Trouble Area

 Open or short in knock sensor 1 circuit  Knock sensor 1 (looseness)  Engine ECU

 Open or short in knock sensor 2 circuit  Knock sensor 2 (looseness)  Engine ECU

If the ECM detects the above diagnosis conditions, it operates the fail–safe function in which the corrective retard angle value is set to the maximum value.

WIRING DIAGRAM

Engine ECU

Knock Sensor 1 (on Right Bank)

Knock Sensor 2 (on Left Bank)

EA1

KNKR

KNKL

LEXUS RX300 (RM785E)

A03315

DI–64

–DIAGNOSTICS ENGINE

INSPECTION PROCEDURE

HINT:

 DTC P0325 is for the right bank knock sensor circuit.  DTC P0330 is for the left bank knock sensor circuit.  Read freeze frame data using hand–held tester or OBD scan tool. Because freeze frame records the

engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. at the time of the malfunction.

1 Connect OBD scan tool or hand–held tester, and check knock sensor circuit.

PREPARATION:

(a) Connect the OBD scan tool or hand–held tester to the

DLC3. (b) Disconnect the wire to wire connector EA1. (c) Connect the terminals of the disconnected EA1 male con-

nector and EA1 female as follows.

Male connector ↔ Female connector

T erminal 1 ↔ T erminal 2 T erminal 2 ↔ T erminal 1

(d) Turn the ignition switch ON and push the OBD scan tool

or hand–held tester main switch ON. (e) After the engine is warmed up, perform quick racing to

4,000 rpm three times.

CHECK:

Check the DTC.

RESULT:

Knock Sensor

Male Connector

EA1

Engine ECU

KNKR

KNKL

Female Connector

FI7050 S06024 S06025

A00304

Type I

Type II

DTC same as when vehicle brought in

P0325 → P0325 or P0330 → P0330

DTC different to when vehicle brought in

P0325 → P0330 or P0330 → P0325

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

DI–65

0.5 V /Division

200 mV /Division

FI6510 FI6607

KNK Signal Waveform

5 msec./Division

100 µsec./Division

Reference: INSPECTION USING OSCILLOSCOPE

 With the engine racing (4,000 rpm), check the waveform

between terminals KNKR, KNKL of the ECM connector

and body ground. HINT: The correct waveform is as shown.

 Spread the time on the horizontal axis, and confirm that

period of the wave is 141 µsec. (Normal mode vibration

frequency of knock sensor: 7.1 kHz) HINT: If normal mode vibration frequency is not 7.1 kHz, the sensor is malfunctioning.

Type II Go to step 3.

A00113

Type I

2 Check for open and short in harness and connector between EA1 connector and

engine ECU (See page IN–32).

NG Repair or replace harness or connector.

Check and replace engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

DI–66

–DIAGNOSTICS ENGINE

3 Check for open and short in harness and connector between EA1 connector and

knock sensor (See page IN–32).ȡ

HINT:

 If DTC P0325 has changed to P0330, check the knock sensor circuit on the right bank side.  If DTC P0330 has changed to P0325, check the knock sensor circuit on the left bank side.

NG Repair or replace harness or connector.

Replace knock sensor.

LEXUS RX300 (RM785E)

DI–67

 Oen or short in crankshaft osition sensor circuit

 Crankshaft position sensor

Starter

–DIAGNOSTICS ENGINE

DI4EB–14

DTC P0335 Camshaft Position Sensor Circuit

Malfunction

CIRCUIT DESCRIPTION

Crankshaft position sensor (NE signal) consist of a signal plate and pick up coil. The NE signal plate has 34 teeth and is mounted on the crankshaft. The NE signal sensor generates 34 signals of every engine revolution. The engine ECU detects the standard crankshaft angle based on the G2 signals, and the actual crankshaft angle the engine speed by the NE signals.

DTC No. DTC Detecting Condition Trouble Area



No crankshaft position sensor signal to engine ECU during

P0335

cranking Open in NE– circuit

WIRING DIAGRAM



  Engine ECU

Right Bank VVT Sensor (Camshaft Position Sensor)

Crankshaft Position Sensor

Left Bank VVT Sensor (Camshaft Position Sensor)

B–W

INSPECTION PROCEDURE

Engine ECU

VV1

NE+

NE–

VV2

A06159

HINT :

 Read freed frame data using hand–held tester. Because freeze frame records the engine conditions

 Perform troubleshooting of DTC P0335 first. If no trouble is found, troubleshoot the following mechani-

cal system.

LEXUS RX300 (RM785E)

DI–68

–DIAGNOSTICS ENGINE

1 Check resistance of crankshaft position sensor (See page IG–14).

VV1, VV2 and NE Signal Waveforms

2V /Division

VV1

VV2

20 msec./Division (Idling)

GND

A11663

Reference: INSPECTION USING OSCILLOSCOPE

During cranking or idling, check between terminals VV1 and NE–, VV2 and NE–, NE+ and NE– of engine ECU. HINT: The correct waveforms are as shown.

NG Replace crankshaft position sensor.

2 Check for open and short in harness and connector between engine ECU and

crankshaft position sensor (See page IN–32).

NG Repair or replace harness or connector.

3 Inspect sensor installation and teeth of signal plate.

NG Tighten the sensor. Replace signal plate.

Check and replace engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

DI–69

P0340

Start

Oen in NE circuit

Engi

ECU

–DIAGNOSTICS ENGINE

DI84C–01

DTC P0340 Camshaft Position Sensor Circuit

Malfunction

CIRCUIT DESCRIPTION

Camshaft position sensor (G(VV) signal) consist of a signal plate and pick up coil. The G(VV) signal plate has one tooth on its outer circumference and is mounted on the camshaft. When the camshafts rotate, the protrusion on the signal plate and the air gap on the pick up coil change, causing fluctuations in the magnetic field and generating an electromotive force in the pick up coil. The NE signal plate has 34 teeth and is mounted on the crankshaft. The NE signal sensor generates 34 signals for every engine revolution. The engine ECU detects the standard crankshaft angle based on the G2+ signals and the actual crankshaft angle and the engine speed by the NE signals.

DTC No.

No camshaft position sensor signal to engine ECU during cranking

Open in NE– circuit

DTC Detecting Condition Trouble Area

 Open or short in camshaft position sensor circuit  Camshaft position sensor



WIRING DIAGRAM

Refer to DTC P0335 on page DI–67.

INSPECTION PROCEDURE

HINT: Read freed frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

1 Check resistance of camshaft position sensor (Signal generator)

(See page IG–1).

Refer to DTC P0335 on page DI–67.

NG Replace camshaft position sensor.

2 Check for open and short in harness and connector between engine ECU and

LEXUS RX300 (RM785E)

camshaft position sensor (See page IN–32).

NG Repair or replace harness or connector.

DI–70

3 Inspect sensor installation.

Check and replace engine ECU (See page IN–32).

–DIAGNOSTICS ENGINE

NG Tighten the sensor.

LEXUS RX300 (RM785E)

DI–71

–DIAGNOSTICS ENGINE

DI84D–01

DTC P0420 Catalyst System Efficiency Below Threshold

CIRCUIT DESCRIPTION

The engine ECU observes the waveform of the oxygen sensor located behind the catalyst to determine whether the catalyst is performance has deteriorated. If the catalyst is performance functioning normally, the waveform of the oxygen sensor located behind the catalyst switches back and forth between rich and lean much more slowly. When the waveform of the oxygen sensor located behind the catalyst alternates flatteringly between rich and lean, it indicates that catalyst performance has deteriorated.

Waveform of A/F Sensor

Normal Catalyst

Abnormal Catalyst

Waveform of Oxygen Sensor Behind Catalyst

DTC No.

After the engine and the catalyst are warmed up, and while the

P0420

LEXUS RX300 (RM785E)

vehicle is driven within the set vehicle and engine speed range, the waveforms of the heated oxygen sensors (bank 1 sensor

2) have the same amplitude (2 trip detection logic)

A01674

DTC Detecting Condition Trouble Area

 Three–way catalytic converter  Open or short in oxygen sensor (bank 1 sensor 2) circuit  Oxygen sensor (bank 1 sensor 2)  Open or short in A/F sensor (bank 1, 2 sensor 1) circuit  A/F sensor (bank 1, 2 sensor 1)

DI–72

–DIAGNOSTICS ENGINE

CONFIRMATION ENGINE RACING PATTERN

Engine Speed

3,000 rpm

2,000 rpm

Idling

IG Switch OFF

(b)

(a)

Warmed Up 3 min. or so

(c)

2 sec.

(d)

Time

2 sec.

Check

A00479

(a) Connect the hand–held tester to the DLC3. (b) Start engine and warm it up with all accessories switched OFF until water temp. is stable. (c) Race the engine at 2,500 – 3,000 rpm for about 3 min. (d) When racing the engine at 3,000 rpm for 2 sec. and 2,000 rpm for 2 sec. alternately, check the wave-

form of the oxygen sensor (bank 1 sensor 2).

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. at the time of the malfunction.

1 Are there any other codes (besides DTC P0420) being output?

YES Go to relevant DTC chart (See page DI–14).

2 Check gas leakage on exhaust system.

NG Repair or replace.

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

3 Check A/F sensor (bank 1 sensor 2) (See page FI–67).

NG Repair or replace.

4 Check oxygen sensor (bank 1 sensor 2) (See page FI–69).

NG Repair or replace.

DI–73

Replace three–way catalytic converter.

LEXUS RX300 (RM785E)

DI–74

–DIAGNOSTICS ENGINE

DI644–06

DTC P0443 Evaporative Emission Control System Purge

Control Vent Control Malfunction

CIRCUIT DESCRIPTION

To reduce HC emissions, evaporated fuel from the fuel tank is routed through the charcoal canister to the intake manifold for combustion in the cylinders. The engine ECU changes the duty signal to the VSV for the EV AP so that the intake quantity of HC emissions is appropriate for the driving conditions (engine load, engine speed, vehicle speed, etc.) after the engine is wamed up.

DTC No.

P0443 Proper response to engine ECU command does not occur

DTC Detecting Condition Trouble Area

WIRING DIAGRAM

Engine Room J/B

EFI

Battery

Relay

F11 Fusible Link Block

W–B

V1 VSV (EVAP)

B–R

 Open or short in VSV circuit for EVAP  VSV for EVAP  Engine ECU

B–W

W–L

W–B

J2 J/C

Engine ECU

MREL

EVAP1

LEXUS RX300 (RM785E)

A14515

DI–75

–DIAGNOSTICS ENGINE

INSPECTION PROCEDURE Hand–held tester:

HINT : Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. at the time of the malfunction.

1 Connect hand–held tester and check operation of VSV for EVAP.

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Turn the ignition switch ON and push the hand–held tes-

ter main switch ON. (c) Select the ACTIVE TEST mode on the hand–held tester.

CHECK:

Check the operation of the VSV when the VSV is operated by the hand–held tester.

OK:

VSV is ON:

Air from port E flows out through port F.

VSV is OFF:

Air from port E is flows out through the air filter.

VSV is ON

Air

VSV is OFF

A14470

OK Check for intermittent problems (See page

DI–3).

2 Check VSV for EV AP (See page FI–59).

NG Replace VSV for EVAP.

3 Check for open and short in harness and connector between EFI main relay and

engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

NG Repair or replace harness or connector.

DI–76

–DIAGNOSTICS ENGINE

Check and replace engine ECU (See page IN–32).

OBD scan tool (excluding hand–held tester):

1 Check VSV for EV AP (See page FI–59).

NG Replace VSV for EVAP.

2 Check voltage between terminal EVP1 of engine ECU connector and body

ground.

EVP1

(+)

PREPARATION:

(a) Remove the engine ECU with connector still connected

(b) Turn the ignition switch ON.

CHECK:

Measure the voltage between terminal EVP1 of the engine ECU connector and body ground.

OK:

BE6653 A10233

A11814

Check and replace engine ECU (See page IN–32).

(See page FI–70).

Voltage: 9 – 14 V

NG Check for open and short in harness and con-

nector between EFI main relay and engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

DI–77

–DIAGNOSTICS ENGINE

DI4ED–13

DTC P0500 Vehicle Speed Sensor Malfunction

CIRCUIT DESCRIPTION

The vehicle speed sensor outputs a 4–pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the engine ECU. The engine ECU determines the vehicle speed based on the frequency of these pulse signals.

4–Pulse 4–Pulse

Vehicle Speed Sensor

Combination Meter

Engine ECU

Transaxle

Q00515 Q00514

DTC No.

No vehicle speed sensor signal to engine ECU under condi-

P0500

tions (a) and (b): (2 trip detection logic) (a) Neutral start switch is OFF (b) Vehicle is being driven

WIRING DIAGRAM

C10 Combination Meter ECU

DTC Detecting Condition Trouble Area

 Open or short in vehicle speed sensor circuit  Vehicle speed sensor  Combination meter  Engine ECU

J/B No. 3

V–W

12 3K3E

V–W

IJ1

V–W

Vehicle Speed Sensor

Engine ECU

SPD

E10

A00223

LEXUS RX300 (RM785E)

A14516

DI–78

–DIAGNOSTICS ENGINE

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. at the time of the malfunction.

1 Check operation of speedometer.

CHECK:

Drive the vehicle and check if the operation of the speedometer in the combination meter is normal. HINT: The vehicle speed sensor is operating normally if the speedometer display is normal.

NG Check speedometer circuit.

2 Check for short in harness and connector between terminal SPD of engine ECU

and body ground.

PREPARATION:

(a) Remove the glove compartment (See page FI–70). (b) Disconnect the E14 connector of engine ECU.

CHECK:

Check continuity between terminal SPD of engine ECU con-

E14 Connector

SPD

A02030

nector and body ground.

OK:

No continuity (1 MΩ or higher)

NG Repair or replace harness or connector.

LEXUS RX300 (RM785E)

DI–79

–DIAGNOSTICS ENGINE

3 Check voltage between terminal SPD of engine ECU connector and body ground.

PREPARATION:

Turn the ignition switch ON.

CHECK:

Measure voltage between terminal SPD of the engine ECU connector and body ground.

OK:

E14 Connector

SPD (+)

A02029

Voltage: 9 – 14 V

NG Check for open in harness and connector be-

tween junction connector and engine ECU (See page IN–32).

4 Check for open in harness and connector between junction connector and com-

bination meter (See page IN–32).

NG Repair or replace harness or connector.

Check and replace engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

DI–80

–DIAGNOSTICS ENGINE

DTC P0505 Idle Control System Malfunction

CIRCUIT DESCRIPTION

The rotary solenoid type ISC valve is located in front of the in-

From Air Cleaner

Throttle Valve

Intake Air Chamber

take air chamber and intake air bypassing the throttle valve is directed to the ISC valve through a passage. In this way the intake air volume bypassing the throttle valve is regulated, controlling the engine speed. The engine ECU operates only the ISC valve to perform idle–up and provide feedback for the target idling speed.

DI84E–01

Signal

DTC No.

P0505

Engine ECU

Valve

To Cylinder

ISC Valve

P01559

DTC Detecting Condition Trouble AreaTrouble Area

Idle speed continues to differ greatly from the target speed

(2 trip detection logic)

 ISC valve is stuck or closed  Open or short in ISC valve circuit  Open or short in A/C switch circuit  Air induction system  Engine ECU

LEXUS RX300 (RM785E)

WIRING DIAGRAM

Engine Room J/B

B–W

–DIAGNOSTICS ENGINE

Engine ECU

MREL

DI–81

F11 Fusible Link Block

Battery

EFI

EFI Relay

W–B

I13 ISC Valve

W–B

Y–R

26 E8

RSO

E01

A14517

W–B

B–R

J2 J/C

INSPECTION PROCEDURE

HINT : Read freeze frame data using a hand–held tester . Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc. at the time of the malfunction.

Hand–held tester:

1 Check operation of the ISC valve.

PREPARATION:

(a) Connect the hand–held tester to the DLC3. (b) Turn the ignition switch ON and push the hand–held tester main switch ON. (c) Select the active test mode on the hand–held tester.

CHECK:

Check the engine speed when the ISC valve operated by the hand–held tester.

OK:

Engine speed is increased and decreased in response to change of ISC duty ratio.

LEXUS RX300 (RM785E)

DI–82

–DIAGNOSTICS ENGINE

OK Check for intermittent problems

(See page DI–3).

2 Check voltage between terminals RSO of engine ECU connector and body

ground.

PREPARATION:

(a) Remove the engine ECU with the connector still con-

(b) Disconnect the E7 connector of the engine ECU. (c) Turn the ignition switch ON.

CHECK:

Measure the voltage between terminals RSO of the engine ECU connector and body ground,

OK:

RSO

(+)

Connector

(–)

A07628

3 Check ISC valve (See page FI–48).

nected (See page FI–70).

Voltage: 9 – 14 V

OK Go to step 4.

NG Replace ISC valve.

Check for open and short in harness and connector between engine room J/B and ISC valve and engine ECU (See page IN–32).

4 Check operation of the ISC valve (See page FI–44).

NG Repair or replace ISC valve.

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

5 Check the blockage of ISC valve and the passage to bypass the throttle valve.

NG Repair or replace ISC valve.

Check and replace engine ECU (See page IN–32).

OBD scan tool (excluding hand–held tester):

1 Check voltage between terminals RSO of engine ECU connector and body

ground.

DI–83

PREPARATION:

(a) Remove the engine ECU with the connector still con-

(b) Disconnect the E7 connector of the engine ECU. (c) Turn the ignition switch ON.

CHECK:

Measure the voltage between terminals RSO of the engine ECU connector and body ground.

OK:

RSO

(+)

Connector

(–)

A07628

2 Check ISC valve (See page FI–48).

nected (See page FI–70).

Voltage: 9 – 14 V

OK Go to step 3.

NG Replace ISC valve.

Check for open and short in harness and connector between engine room J/B and ISC valve and engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

DI–84

–DIAGNOSTICS ENGINE

3 Check operation of the ISC valve (See page FI–44).

NG Repair or replace ISC valve.

4 Check the blockage of ISC valve and the passage to bypass the throttle valve.

NG Repair or replace ISC valve.

Check and replace engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

DTC P1130 A/F Sensor Circuit Range/Performance Mal-

function (Bank 1 Sensor 1)

DTC P1150 A/F Sensor Circuit Range/Performance Mal-

function (Bank 2 Sensor 1)

CIRCUIT DESCRIPTION

Refer to DTC P0125 on page DI–42.

DI–85

DI2H7–06

DTC No.

P1130 P1150

Voltage output* of A/F sensor remains at 3.8 V or more, or 2.8

V or less, during engine running after the engine is warmed up

(2 trip detection logic)

*: Output value changes at inside of engine ECU only

Voltage output* of A/F sensor does not change from 3.30 V,

during engine running after the engine is warmed up (2 trip

detection logic)

*: Output value changes at the inside of engine ECU only

Open or short in A/F sensor circuit (2 trip detection logic)

DTC Detecting Condition Trouble Area

 Open or short in A/F sensor circuit  A/F sensor  Air induction system  Fuel pressure  Injector  Engine ECU

HINT:

 After confirming DTC P1130, use the OBD scan tool or hand-held tester to confirm voltage output of

A/F sensor (AFS B1 S1/O2S B1 S1) from the CURRENT DATA.

 The A/F sensor's output voltage and the short-term fuel trim value can be read using the OBD scan

tool or hand-held tester.

 The ECM controls the voltage of the AFR+, AFL+, AFR- and AFL- terminals of the engine ECU to

the fixed voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without the OBD scan tool or hand–held tester.

 OBD scan tool (excluding hand-held tester) displays the one fifth of the A/F sensor output voltage

which is displayed on the hand-held tester.

WIRING DIAGRAM

Refer to DTC P0125 on page DI–42.

LEXUS RX300 (RM785E)

DI–86

CONFIRMATION DRIVING PATTERN

Vehicle Speed

–DIAGNOSTICS ENGINE

60 – 120 km/h

(38 – 75 mph)

Idling

IG SW OFF

(c)

(a)(b)

(d)

3 – 5 min.

Time

A00364

(a) Connect the hand–held tester to the DLC3. (b) Switch the hand–held tester from the normal mode to the check mode (See page DI–3). (c) Start the engine and warm it up with all the accessory switches OFF. (d) Drive the vehicle at 60 – 120 km/h (38 – 75 mph) and engine speed at 1,400 – 3,200 rpm for 3 – 5 min. HINT : If a malfunction exists, the check engine warning light will light up during step (d).

NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction will not be possible. If you do not have a hand–held tester , turn the ignition switch OFF after performing steps (c) and (d), then perform steps (c) and (d) again.

INSPECTION PROCEDURE

HINT:

 If DTC P1130 is displayed, check Bank 1 Sensor 1 circuit.  If DTC P1150 is displayed, check Bank 2 Sensor 1 circuit.  Read freeze frame data using hand–held tester or OBD scan tool. Because freeze frame records the

1 Are there any other codes (besides DTC P1130, P1150) being output?

YES Go to relevant DTC chart (See page DI–14).

LEXUS RX300 (RM785E)

DI–87

V*)

–DIAGNOSTICS ENGINE

2 Check output voltage of A/F sensor.

PREPARATION:

(a) Connect the OBD scan tool or hand–held tester to the DLC3. (b) Warm up the A/F sensor with the engine speed at 2,500 rpm for approx. 90 sec.

CHECK:

Read the voltage value of the A/F sensor on the screen of OBD scan tool or hand–held tester when you perform all the following conditions. HINT: The voltage of the AFR+ or AFL+ terminal of the engine ECU is fixed at 3.3 V and the voltage of the AFR– or AFL– terminal is fixed at 3.0 V. Therefore, it is impossible to check the A/F sensor output voltage at the terminals (AFR+, AFL+/AFR–, AFL–) of the engine ECU.

OK:

Condition A/F Sensor Voltage Value Engine idling Engine racing Driving at engine speed 1,500 rpm or more and vehicle

speed 40 km/h (25 mph) or more, and operate throttle valve open and close

HINT:

 During fuel enrichment, there is a case that the output voltage of the A/F sensor is below 2.8 V (0.56

V*), it is normal.

 During fuel cut, there is a case that the output voltage of the A/F sensor is above 3.8 V (0.76 V*), it

is normally.

 If the output voltage of the A/F sensor remains at 3.30 V (0.660 V*) even after performing all the above

conditions, the A/F sensor circuit may be open.

 If the output voltage of the A/F sensor remains at 3.8 V (0.76 V*) or more, or 2.8 V (0.56 V*) or less

even after performing all the above conditions, the A/F sensor circuit may be short.

*: When you use the OBD scan tool (excluding hand–held tester).

 Not remains at 3.30 V (0.660 V*)



ot remains at 3.8 V (0.76  Not remains at 2.8 V (0.56 V*) or less *: When you use OBD II scan tool (excluding TOYOT A hand–held tester)

or more

OK Go to step 9.

3 Check for open and short in harness and connector between engine ECU and

A/F sensor (See page IN–32).

NG Repair or replace harness or connector.

LEXUS RX300 (RM785E)

DI–88

–DIAGNOSTICS ENGINE

4 Check resistance of A/F sensor heater (See page FI–67).

NG Replace A/F sensor.

5 Check air induction system (See page FI–1).

NG Repair or replace.

6 Check fuel pressure (See page FI–5).

NG Check and repair fuel pump, pressure regulator,

7 Check injector injection (See page FI–22).

NG Replace injector.

Replace A/F sensor.

fuel pipe line and filter (See page FI–5).

8 Perform confirmation driving pattern (See page DI–85).

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

9 Is there DTC P1130 or P1150 being output again?

YES Check and replace engine ECU

(See page IN–32).

10 Did vehicle runs out of fuel in past?

NO Check for intermittent problems

(See page DI–3).

DI–89

YES

DTC P1 130 or P1 150 is caused by running out of fuel.

LEXUS RX300 (RM785E)

DI–90

–DIAGNOSTICS ENGINE

DTC P1133 A/F Sensor Circuit Response Malfunction

(Bank 1 Sensor 1)

DTC P1153 A/F Sensor Circuit Response Malfunction

(Bank 2 Sensor 1)

CIRCUIT DESCRIPTION

Refer to DTC P0125 on page DI–42.

DI2H8–06

DTC No.

P1133 P1153

After engine is warmed up, and during vehicle driving at engine speed 1,400 rpm or more and vehicle speed 60 km/h (38 mph) or more, if the response characteristic of A/F sensor becomes deteriorated (2 trip detection logic)

DTC Detecting Condition Trouble Area

 Open or short in A/F sensor circuit  A/F sensor  Air induction system  Fuel pressure  Injector  Engine ECU

WIRING DIAGRAM

Refer to DTC P0125 on page DI–42.

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand–held tester or OBD scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. at the time of the malfunction.

1 Are there any other codes (besides DTC P1133, P1153) being output?

YES Go to relevant DTC chart (See page DI–14).

2 Connect OBD scan tool or hand–held tester, and read value for voltage output of

A/F sensor.

PREPARATION:

(a) Connect the OBD scan tool or hand–held tester to the DLC3. (b) Warm up the A/F sensor with the engine speed at 2,500 rpm for approx. 90 sec.

CHECK:

Read the voltage of the A/F sensor on the screen of the OBD scan tool or hand–held tester when you perform all the following conditions.

LEXUS RX300 (RM785E)

DI–91

V*)

–DIAGNOSTICS ENGINE

HINT: The voltage of the AFR+ or AFL+ terminal of the engine ECU is fixed at 3.3 V and the voltage of the AFR– or AFL– terminal is fixed at 3.0 V. Therefore, it is impossible to check the A/F sensor output voltage at the terminals (AFR+, AFL+/AFR–, AFL–) of the engine ECU.

OK:

Condition A/F Sensor V oltage value Engine idling Engine racing Driving at engine speed 1,500 rpm or more and vehicle

speed 40 km/h (25 mph) or more, and operate throttle valve open and close

 Not remains at 3.30 V (0.660 V*)



ot remains at 3.8 V (0.76  Not remains at 2.8 V (0.56 V*) or less *: When you use the OBD scan tool (excluding hand–held tester)

or more

HINT:

 During fuel enrichment, there is a case that the output voltage of the A/F sensor is below 2.8 V (0.56

V*), it is normal.

 During fuel cut, there is a case that the output voltage of the A/F sensor is above 3.8 V (0.76 V*), it

is normal.

 If the output voltage of the A/F sensor remains at 3.30 V (0.660 V*) even after performing all the above

conditions, the A/F sensor circuit may be open.

 If the output voltage of the A/F sensor remains at 3.8 V (0.76V*) or more, or 2.8 V (0.56 V*) or less even

after performing all the above conditions, the A/F sensor circuit may be short.

*: When you use the OBD scan tool (excluding hand–held tester).

OK Go to step 9.

3 Check for open and short in harness and connector between engine ECU and

A/F sensor (See page IN–32).

NG Repair or replace harness or connector.

4 Check resistance of A/F sensor heater (See page FI–67).

NG Replace A/F sensor.

LEXUS RX300 (RM785E)

DI–92

5 Check air induction system (See page FI–1).

NG Repair or replace.

6 Check fuel pressure (See page FI–5).

NG Check and repair fuel pump, pressure regulator,

–DIAGNOSTICS ENGINE

fuel pipe line and filter (See page FI–5).

7 Check injector injection (See page FI–22).

NG Replace injector.

Replace A/F sensor.

8 Perform confirmation driving pattern (See page DI–85).

9 Is there DTC P1133 or P1153 being output again?

LEXUS RX300 (RM785E)

YES Check and replace engine ECU

(See page IN–32).

10 Did vehicle runs out of fuel in past?

NO Check for intermittent problems

YES

DTC P1 133 or P1 153 is caused by running out of fuel.

DI–93

–DIAGNOSTICS ENGINE

(See page DI–3).

LEXUS RX300 (RM785E)

DI–94

P1135

–DIAGNOSTICS ENGINE

DTC P1135 A/F Sensor Heater Circuit Malfunction (Bank

1 Sensor 1)

DTC P1155 A/F Sensor Heater Circuit Malfunction (Bank

2 Sensor 1)

CIRCUIT DESCRIPTION

Refer to DTC P0125 on page DI–42.

DI2H9–06

DTC No.

P1135 P1155

When the heater operates, heater current exceeds 8 A

Heater current of 0.25 A or less when the heater operates

DTC Detecting Condition Trouble Area

 Open or short in heater circuit of A/F sensor  A/F sensor heater  Engine ECU

WIRING DIAGRAM

Refer to DTC P0125 on page DI–42.

INSPECTION PROCEDURE

1 Check voltage between terminals HAFL, HAFR of engine ECU connector and

body ground.

HAFL

HAFR

(+)

(–)

A02032

PREPARATION:

(a) Remove the glove compartment (See page FI–70). (b) Turn the ignition switch ON.

CHECK:

Measure the voltage between terminals HAFL, HAFR of the engine ECU connector and body ground.

OK:

Voltage: 9 – 14 V

OK Check and replace engine ECU (See page

IN–32).

LEXUS RX300 (RM785E)

–DIAGNOSTICS ENGINE

2 Check resistance of A/F sensor heater (See page FI–56).

NG Replace A/F sensor.

3 Check A/F sensor heater relay (Marking: A/F) (See page FI–56).

NG Replace A/F sensor heater relay.

DI–95

Check and repair harness or connector between A/F sensor heater relay and A/F sensor, and A/F sensor and engine ECU (See page IN–32).

LEXUS RX300 (RM785E)

DI–96

–DIAGNOSTICS ENGINE

DTC P1300 Igniter Circuit Malfunction (No. 1)

DTC P1305 Igniter Circuit Malfunction (No. 2)

DTC P1310 Igniter Circuit Malfunction (No. 3)

DTC P1315 Igniter Circuit Malfunction (No. 4)

DTC P1320 Igniter Circuit Malfunction (No.5)

DI84F–01

DTC P1325 Igniter Circuit Malfunction (No.6)

CIRCUIT DESCRIPTION

A Direct Ignition System (DIS) has been adopted. The DIS improves the ignition timing accuracy, reduces high–voltage loss, and enhances the the overall reliability of the ignition system by eliminating the distributor . The DIS is a 1–cylinder ignition system which ignites one cylinder with one ignition coil. In the 1–cylinder ignition system, the one spark plug is connected to the end of the secondary winding. High voltage generated in the secondary winding is applied directly to the spark plug. The spark of the spark plug pass from the center electode to the ground electrode. The engine ECU determines ignition timing and outputs the ignition signals (IGT) for each cylinder. Based on IGT signals, the power transistors in the igniter cuts off the current to the primary coil in the ignition coil is supplied to the spark plug that are connected to the end of the secondary coil. At the same time, the igniter also sends an ignition confirmation signal (IGF) as a fail–safe measure to the engine ECU.

DTC No.

P1300 P1305 P1310 P1315 P1320 P1325

No IGF signal to engine ECU while engine is running

DTC Detecting Condition Trouble Area

 Open or short in IGF and IGT1 – 6 circuit from

ignition coil with igniter

 No. 1 – No. 6 ignition coil with igniter  Engine ECU

LEXUS RX300 (RM785E)

WIRING DIAGRAM

DI–97

–DIAGNOSTICS ENGINE

Instrument Panel J/B

I15 Ignition Switch

IG2

Engine Room J/B

F11 FL Block

Battery

(*1): LHD (*2): RHD

AM2

I1 Ignition Coil

W–R

IH1

W–R

W–L (*1) W–R (*2)

W–B I3 Ignition Coil

W–R

and Igniter No. 1

W–B

4 1

I2 Ignition Coil and Igniter No. 2

W–B

3 2

L–R

and Igniter No. 3

Y–G

B–Y

W–R

W–B B

W–B

I4 Ignition Coil and Igniter No. 4

W–B

I5 Ignition Coil and Igniter No. 5

L–Y

W–B

Engine ECU

11 E8

IGT1

IGT2

IGT3

IGF

IGT4

IGT5

W–R

W–B

I6 Ignition Coil and Igniter No. 6

W–B

G–B

16 E8

IGT6

W–R

W–B

Noise Filter

A14518

INSPECTION PROCEDURE

HINT :

 If DTC P1300 is displayed, check No. 1 ignition coil with igniter circuit.  If DTC P1305 is displayed, check No. 2 ignition coil with igniter circuit.  If DTC P1310 is displayed, check No. 3 ignition coil with igniter circuit.  If DTC P1315 is displayed, check No. 4 ignition coil with igniter circuit.  If DTC P1320 is displayed, check No. 5 ignition coil with igniter circuit.  If DTC P1325 is displayed, check No. 6 ignition coil with igniter circuit.  Read freeze frame data using hand–held tester. Because freeze frame records the engine conditions

LEXUS RX300 (RM785E)

DI–98

–DIAGNOSTICS ENGINE

1 Check spark plug and spark (See page IG–1).

NG Go to step 4.

2 Check for open and short in harness and connector in IGF and IGT signal circuit

between engine ECU and ignition coil with igniter (See page IN–32).

NG Repair or replace harness or connector.

3 Disconnect ignition coil with igniter connector, and check voltage between

terminals IGF of engine ECU connector and body ground.

PREPARATION:

(a) Remove the engine ECU with connector still connected

(See page FI–70). (b) Disconnect the ignition coil with the igniter connector. (c) Turn the ignition switch ON.

CHECK:

Measure voltage between terminals IGF of the engine ECU connector and body ground.

OK:

Voltage: 4.5 – 5.5 V

OK Replace ignition coil with igniter.

IGF

(+)

(–)

A02033

Check and replace engine ECU (See page IN–32).

4 Check for open and short in harness and connector in IGT signal circuit between

engine ECU and ignition coil with igniter (See page IN–32).

LEXUS RX300 (RM785E)

Lexus Car Fault Codes DTC LEXUS Car Fault Codes DTC

Specifications and Main Features

Frequently Asked Questions

User Manual