ISUZU NKR, NPR, NQR Service Manual

WORKSHOP MANUAL
NKR . NPR . NQR
ANTI-LOCK BRAKE SYSTEM
(ABS)
SECTION 5A4
HOME
SECTION 5A4
ANTI-LOCK BRAKE SYSTEM (ABS)
Service Precaution
CAUTION: Always use the correct fastener in the proper location. When you replace a fastener, use ONLY the exact part number for that application. ISUZU will call out those fasteners that require a replacement after removal. ISUZU will also call out the fasteners that require thread lockers or thread sealant. UNLESS OTHERWISE SPECIFIED, do not use supplemental coatings (Paints, greases, or other corrosion inhibitors) on threaded fasteners or fastener joint interfaces. Generally, such coatings adversely affect the fastener torque and the joint clamping force, and may damage the fastener. When you install fasteners, use the correct tightening sequence and specifications. Following these instructions can help you avoid damage to parts and systems.
CONTENTS
PAGE
Service Precaution..........................................................................................................5A4 -1
General Description ........................................................................................................5A4 -5
System Components..................................................................................................5A4 -6
Electronic Hydraulic Control Unit (EHCU)................................................................5A4 -6
Hydraulic Unit (HU).....................................................................................................5A4 -6
ABS Warning Light.....................................................................................................5A4 -6
Wheel Speed Sensor ..................................................................................................5A4 -6
Normal and Anti-lock Braking....................................................................................5A4 -6
Brake Pedal Travel......................................................................................................5A4 -7
Acronyms and Abbreviations ....................................................................................5A4 -7
General Diagnosis...........................................................................................................5A4 -7
General Information....................................................................................................5A4 -7
ABS Service Precautions...........................................................................................5A4 -7
Computer System Service Precautions....................................................................5A4 -7
General Service Precautions.....................................................................................5A4 -8
Note on Intermittents..................................................................................................5A4 -8
Test Driving ABS Complaint Vehicles.......................................................................5A4 -8
“ABS” Warning Light..................................................................................................5A4 -8
Normal Operation .......................................................................................................5A4 -8
Basic Diagnostic Flow Chart .....................................................................................5A4 -9
Basic Inspection Procedure.......................................................................................5A4 -9
5A4-2 ANTI-LOCK BRAKE SYSTEM (ABS)
Tech 2 Scan Tool ........................................................................................................5A4 -10
Tech 2 Features ..........................................................................................................5A4 -11
Getting Started............................................................................................................5A4 -11
Operating Procedure (For Example).........................................................................5A4 -12
DTC Modes..................................................................................................................5A4 -13
DTC Information Mode ...............................................................................................5A4 -13
Plotting Snapshot Graph............................................................................................5A4 -14
Plotting Graph Flow Chart (Plotting graph after obtaining vehicle information)..5A4 -15
Flow Chart for Snapshot Replay (Plotting Graph) ...................................................5A4 -16
Tech 2 Data Display....................................................................................................5A4 -17
Special Function.........................................................................................................5A4 -17
EHCU Connector Pin-out Checks..............................................................................5A4 -21
Circuit Diagram...........................................................................................................5A4 -22
Connector List ............................................................................................................5A4 -26
Part Location...............................................................................................................5A4 -29
Symptom Diagnosis........................................................................................................5A4 -30
Chart A-1 ABS Works Frequently But Vehicle Does Not Decelerate......................5A4 -30
Chart TA-1 ABS Works Frequently But Vehicle
Does Not Decelerate (Use TECH 2)...........................................................................5A4 -30
Chart A-2 Uneven Braking Occurs While ABS Works.............................................5A4 -31
Chart A-3, TA-3 The Wheels Are Locked...................................................................5A4 -31
Chart A-4 Brake Pedal Feed Is Abnormal .................................................................5A4 -32
Chart A-5, TA-5 Braking Sound (From Hydraulic Unit)
Is Heard While Not Braking........................................................................................5A4 -33
Diagnostic Trouble Codes..............................................................................................5A4 -34
Diagnosis By “ABS” Warning Light Illumination Pattern ............................................5A4 -35
Diagnostic Trouble Codes (DTCs).............................................................................5A4 -35
Chart B-1-1 With the key in the ON position (Before starting the engine).
Warning light (W/L) is not activated..........................................................................5A4 -39
Chart 1 (DTC 13/C0213) Vehicle Type Error..............................................................5A4 -40
Chart 2 (DTC 14/C0214) Low Power Voltage of
Rear Sensor or EHCU Abnormality ...........................................................................5A4 -40
Chart 3 (DTC 15/C0215) Low Power Voltage OUT of Range ...................................5A4 -41
Chart 4 (DTC 25/C0225) Exhaust Brake Cut Circuit Abnormality ...........................5A4 -42
Chart 5 (DTC 33/C0233) Motor Drive Circuit Abnormality .......................................5A4 -42
Chart 6 (DTC 34/C0234) Abnormal Motor Rotation..................................................5A4 -42
Chart 7 (DTC 41/C0241) Solenoid Valve Power Supply Abnormality .....................5A4 -43
Chart 8 (DTC 43, 45/C0243, C0245) Solenoid Valve Circuit Abnormality...............5A4 -43
Chart 9 (DTC 51/C0251) FL Speed Sensor Circuit Abnormality..............................5A4 -43
Chart 10 (DTC 52/C0252) FR Speed Sensor Circuit Abnormality............................5A4 -43
Chart 11 (DTC 53/C0253) RL Speed Sensor Circuit Abnormality............................5A4 -44
Chart 12 (DTC 54/C0254) RR Speed Sensor Circuit Abnormality...........................5A4 -45
Chart 13 (DTC 61/C0261) Abnormal FL Speed Sensor Signal.................................5A4 -46
Chart 14 (DTC 62/C0262) Abnormal FR Speed Sensor Signal................................5A4 -48
Chart 15 (DTC 63/C0263) Abnormal RL Speed Sensor Signal................................5A4- 50
Chart 16 (DTC 64/C0264) Abnormal RR Speed Sensor Signal................................5A4- 51
Chart 17 (DTC 65/C0265) Tire Size Error...................................................................5A4- 52
Unit Inspection Procedure..............................................................................................5A4- 53
Chart C-1-1 FL Speed Sensor Output Inspection Procedure..................................5A4- 53
Chart C-1-2 FR Speed Sensor Output Inspection Procedure..................................5A4- 54
Chart C-1-3 RL Speed Sensor Output Inspection Procedure..................................5A4- 55
Chart C-1-4 RR Speed Sensor Output Inspection Procedure.................................5A4- 57
Chart TC-1 Sensor Output Inspection Procedure (Use TECH 2) ............................5A4- 58
Electronic Hydraulic Control Unit (EHCU).....................................................................5A4- 59
Removal.......................................................................................................................5A4- 59
Installation...................................................................................................................5A4- 59
Front Speed Sensor ........................................................................................................5A4- 60
Front Speed Sensor and Associated Parts ..............................................................5A4- 60
Removal.......................................................................................................................5A4- 60
Inspection and Repair ................................................................................................5A4- 60
Installation...................................................................................................................5A4- 60
Front Speed Sensor Rotor..............................................................................................5A4- 61
Front Speed Sensor Rotor and Associated Parts....................................................5A4- 61
Removal.......................................................................................................................5A4- 61
Inspection and Repair ................................................................................................5A4- 62
Installation...................................................................................................................5A4- 62
Rear Speed Sensor .........................................................................................................5A4- 6 3
Rear Speed Sensor and Associated Parts................................................................5A4- 63
Removal.......................................................................................................................5A4- 64
Inspection and Repair ................................................................................................5A4- 64
5A4-4 ANTI-LOCK BRAKE SYSTEM (ABS)
Installation...................................................................................................................5A4- 64
Rear Speed Sensor Rotor...............................................................................................5A4- 65
Rear Speed Sensor Rotor and Associated Parts.....................................................5A4- 65
Removal.......................................................................................................................5A4- 65
Inspection and Repair ................................................................................................5A4- 65
Installation...................................................................................................................5A4- 65
Special Tools ...................................................................................................................5A4- 67
General Description
The Anti-lock Brake System (ABS) works on all four wheels. A combination of wheel speed sensor and Electronic Hydraulic Control Unit (EHCU) can
ABS
9 6
CAB
DIAG
TO EHCU
10
TO EHCU
1 2
4
3
EHCU
EXH BRAKE CUT RELAY
ELECTRONIC HYDRAULIC CONTROL UNIT(EHCU)
HYDRAULIC UNIT(HU)
determine when a wheel is about to stop turning and adjust brake pressure to maintain best braking.
This system helps the drive maintain greater control of the vehicle under heavy braking conditions.
ENGINE CONTROLLER
OR
TO EHCU
5
7
4
8
Legend
(1) Hydraulic Line (7) Load Sensing Proportioning Valve (LSPV) (2) Electronic Line (8) Battery (3) Electronic Hydraulic Control Unit (EHCU) (9) ABS Warning Light (4) Front Wheel Speed Sensor (10) Brake Switch (5) Rear Wheel Speed Sensor (6) Diagnosis Connector
5
5A4-6 ANTI-LOCK BRAKE SYSTEM (ABS)
System Components
The Anti-lock Brake System consists of a Electronic Hydraulic Control Unit (EHCU), four Wheel Speed Sensors and Warning Light.
Electronic Hydraulic Control Unit (EHCU)
The EHCU consists of Electronic Brake Control Module (EBCM) and Hydraulic Unit (HU).
The EHCU is located at the frame side, in front of rear spring bracket.
The EHCU consists of ABS control circuits, fault detector, and a fail-safe. It drives the hydraulic unit according to the signal from each sensor, cancelling ABS to return to normal braking when a malfunction has occurred in the ABS.
The EHCU is self-diagnosing function which can indicate faulty circuits during diagnosis.
CONNECTOR
EHCU
Tang lock
PushPush
Lever
Move lever outside
ABS Warning Light
Vehicles equipped with the Anti-lock Brake System has an amber “ABS” warning light in the instrument panel. The “ABS” warning light will illuminate if a malfunction in the Anti-lock Brake System is detected by the Electronic Hydraulic Control Unit (EHCU). In case of an electronic malfunction, the EHCU will turn “ON” the “ABS” warning light and disable the Anti-lock braking function.
The “ABS” light will turn “ON” for 2 seconds after the ignition switch is to the “ON” position, and then will go out.
If the “ABS” light comes “ON” and stays “ON” while driving, the Anti-lock Brake System should be inspected for a malfunction according to the diagnosis procedure.
NOTE: When disconnecting harness connector from EHCU,
push the tang lock of the connector ( release the tang lock. Then move the lever.
portion) and
Hydraulic Unit (HU)
It consists of a Motor, Plunger Pump, Solenoid Valves and Check Valve.
Solenoid Valves: Reduces or holds the caliper fluid pressure for each front disc brake or both rear drum brakes according to the signal sent from the EHCU.
Reservoir: Temporarily holds the brake fluid that returns from the front and rear wheel brake so that pressure of front wheel brake can be reduced smoothly.
Plunger Pump: Feeds the brake fluid held in the reservoir to the master cylinder.
Motor: Drives the pump according to the signal from EHCU. Check Valve: Controls the brake fluid flow.
Wheel Speed Sensor
It consists of a sensor and a rotor. The sensor is attached to the knuckle on the front wheels and to the bracket on the brake back plate on the rear wheels. The front speed sensor is coil type and rear is Hall IC type.
The sensor rotors press-fitted to front and rear wheel hubs output pulse frequency depending on wheel rotation.
The speed sensors find vehicle speed from its frequency.
Normal and Anti-lock Braking
Under normal driving conditions, the Anti-lock Brake System functions the same as a standard power assisted brake system. However, with the detection of wheel lock-up, a slight bump or kick-back will be felt in the brake pedal. This pedal “bump” will be followed by a series of short pedal pulsations which occurs in rapid succession. The brake pedal pulsation will continue
until there is no longer a need for the anti-lock function or until the vehicle is stopped. A slight ticking or popping noise may be heard during brake applications when the Anti-lock features is being used.
When the Anti-lock feature is being used, the brake pedal may rise even as the brakes are being applied.
This is also normal. Maintaining a consist force on the pedal will provide the shortest stopping distance.
Brake Pedal Travel
Vehicles equipped with the Anti-lock Brake System may be stopped by applying normal force to the brake pedal. Although there is no need to push the pedal beyond the point where it stops or holds the vehicle, by applying more force the pedal will continue to travel toward the floor.
This extra brake pedal travel is normal.
Acronyms and Abbreviations
Several acronyms and abbreviations are commonly used throughout this section:
ABS
Anti-lock Brake System
CKT
Circuit
DLC
Data Link Connector
DTC
Diagnostic Trouble Code
DVM
Digital Volt Meter (High Impedance Multimeter)
EHCU
Electronic Hydraulic Control Unit
FL
Front Left
FR
Front Right
GEN
Generator
HU
Hydraulic Unit
MV
Millivolts
RL
Rear Left
RR
Rear Right
RPS
Revolution per Second
SW
Switch
VDC
Volts DC
VAC
Volts AC
W/L
Warning Light
WSS
Wheel Speed Sensor
General Diagnosis
General Information
ABS malfunction can be classified into two types, those which can be detected by the ABS warning light and those which can be detected as a vehicle abnormality by the driver.
In either case, locate the fault in accordance with the “BASIC DIAGNOSTIC FLOWCHART” and repair.
Please refer to Section 5A for the diagnosis of mechanical troubles such as brake noise, brake judder (brake pedal or vehicle vibration felt when braking), uneven braking, and parking brake trouble.
ABS Service Precautions
Required Tools and Items:
Box Wrench
Brake Fluid
Special Tool
Some diagnosis procedures in this section require the installation of a special tool.
5-8840-0285-0 (J-39200) High Impedance Multimeter
When circuit measurements are requested, use a circuit tester with high impedance.
Computer System Service Precautions
The Anti-lock Brake System interfaces directly with the Electronic Hydraulic Control Unit (EHCU) which is a control computer that is similar in some regards to the Engine Control Module. These modules are designed to withstand normal current draws associated with vehicle operation. However, care must be taken to avoid overloading any of the EHCU circuits. In testing for opens or shorts, do not ground or apply voltage to any of the circuits unless instructed to do so by the appropriate diagnostic procedure. These circuits should only be tested with a high impedance multimeter 5-8840-0285-0 (J-39200) or special tools as described in this section. Power should never be removed or applied to any control module with the ignition in the “ON” position. Before removing or connecting battery cables, fuses or connectors, always turn the ignition switch to the “OFF” position.
5A4-8 ANTI-LOCK BRAKE SYSTEM (ABS)
General Service Precautions
The following are general precautions which should be observed when servicing and diagnosing the Anti-lock Brake System and/or other vehicle systems. Failure to observe these precautions may result in Anti-lock Brake System damage.
If welding work is to be performed on the vehicle
using an electric arc welder, the EHCU connector should be disconnected before the welding operation begins.
The EHCU connector should never be connected
or disconnected with the ignition “ON”.
The EHCU is not separately serviceable and must
be replaced as assemblies. Do not disassemble any component which is designated as non­serviceable in this Section.
If only rear wheels are rotated using jacks or drum
tester, the system will diagnose a speed sensor malfunction and the “ABS” warning light will illuminate. But actually no trouble exists. After inspection stop the engine once and re-start it, then make sure that the “ABS” warning light does not illuminate.
If the battery has been discharged
The engine may stall if the battery has been completely discharged and the engine is started via jumper cables. This is because the Anti-lock Brake System (ABS) requires a large quantity of electricity. In this case, wait until the battery is recharged, or set the ABS to a non-operative state by removing the fuse for the ABS. After the battery has been recharged, stop the engine and install the ABS fuse. Start the engine again, and confirm that the ABS warning light does not light.
Note on Intermittents
As with virtually any electronic system, it is difficult to identify an intermittent failure. In such a case duplicating the system malfunction during a test drive or a good description of vehicle behavior from the customer may be helpful in locating a “most likely” failed component or circuit. The symptom diagnosis chart may also be useful in isolating the failure. Most intermittent problems are caused by faulty electrical connections or wiring. When an intermittent failure is encountered, check suspect circuits for:
Suspected harness damage.
Poor mating of connector halves or terminals not
fully seated in the connector body (backed out).
Improperly formed or damaged terminals.
Test Driving ABS Complaint Vehicles
In case that there has been an malfunction in the lighting pattern of “ABS” warning light, the fault can be located in accordance with the “DIAGNOSIS BY “ABS” WARNING LIGHT ILLUMINATION PATTERN”. In
case of such trouble as can be detected by the driver as a vehicle symptom, however, it is necessary to give a test drive following the test procedure mentioned below, thereby reproducing the symptom for trouble diagnosis on a symptom basis:
1. Start the engine and make sure that the “ABS” W/L goes OFF. If the W/L remains ON, it means that the Diagnostic Trouble Code (DTC) is stored. Therefore, read the code and locate the fault.
2. Start the vehicle and accelerate to about 30km/h (19 mph) or more.
3. Slowly brake and stop the vehicle completely.
4. Then restart the vehicle and accelerate to about 40 km/h (25 mph) or more.
5. Brake at a time so as to actuate the ABS and stop the vehicle.
6. Be cautious of abnormality during the test. If the W/L is actuated while driving, read the DTC and locate the fault.
7. If the abnormality is not reproduced by the test, make best efforts to reproduce the situation reported by the customer.
8. If the abnormality has been detected, repair in accordance with the “SYMPTOM DIAGNOSIS”.
NOTE:
Be sure to give a test drive on a wide, even road with little traffic.
If an abnormality is detected, be sure to suspend the test and start trouble diagnosis at once.
“ABS” Warning Light
When ABS trouble occurs and actuates when possible the “ABS” warning light, the trouble code corresponding to the trouble is stored in the EHCU. Only the ordinary brake system is available when the ABS is turned OFF. When the “ABS” warning light is actuated, if the starter switch is set ON after setting it OFF once, the EHCU checks up on the entire system and, if there is no abnormality, judges ABS to work currently and the warning light works normally even though the trouble code is stored.
NOTE: Illumination of the “ABS” warning light indicates that anti-lock braking is no longer available. Power assisted braking without anti-lock control is still available.
Normal Operation
“ABS” Warning Light
When the ignition is first moved from “OFF” to “ON”, the amber “ABS” warning light will turn “ON” for 2 seconds and will turn “OFF”.
Basic Diagnostic Flow Chart
Step Action Yes No
1 1. Customer complaint.
2. Questioning to customer.
3. Basic inspection (Refer to “Basic inspection procedure”)
Using TECH 2?
2 Make sure of DTC by TROUBLE CODE.
Is EHCU including DTC?
3 Check if the DTC is stored.
Is EHCU including DTC?
4 Test drive.
Is W/L lit?
5 1. Repair of faulty part.
2. Elimination of DTC.
3. Inspection of “ABS” W/L illumination pattern with ignition SW “ON”.
4. Test drive.
Does repeat trouble?
6 1. Reconnect all components and ensure all components
are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Go to Step 2 Go to Step 3
Go to Step 5 Go to Step 4
Go to Step 5 Go to Step 4
Go to Step 5 Trouble diagnosis
based on symptom
(Refer to
“SYMPTOM
DIAGNOSIS”) Go
to Step 5
Repeat the
diagnosis of the
symptom or DTC
appears again Go
to Step 1
Finished Go to Step 6
Go to Step 6
Basic Inspection Procedure
1. Basic Inspection of Service Brake Step Action Yes No
1 Is the fluid level normal? Go to Step 2 Replenish with
fluid.
Go to Step 2
2 Does fluid leak? Repair.
Go to Step 3
3 Is the booster functioning normal? Go to Step 4 Repair.
4 Is the pad and rotor normal? Go to Step 5 Repair.
5 Reconnect all components and ensure all components are
properly mounted. Was this step finished?
2. Ground Inspection Step Action Yes No
1 Are ABS-related ground points ok? Go to Step 2 Repair.
2 Reconnect all components and ensure all components are
properly mounted. Was this step finished?
Finished Go to Step 5
Finished Go to Step 2
Go to Step 3
Go to Step 4
Go to Step 5
Go to Step 2
5A4-10 ANTI-LOCK BRAKE SYSTEM (ABS)
Tech 2 Scan Tool
From 98 MY, Isuzu dealer service departments are recommended to use Tech 2. Please refer to Tech 2 scan tool user guide.
Legend
(1) PCMCIA Card (4) DLC Cable (2) RS 232 Loop Back Connector (5) Tech-2 (3) SAE 16/19 Adapter
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-11
Tech 2 Features
1. Tech 2 is a 12 volt system. Do not apply 24 volt.
2. After connecting and/or installing the Vehicle Communications Interface (VCI) module, PCMCIA card and DLC connector to the Tech 2, connect the tool to the vehicle DLC.
3. Make sure the Tech 2 is powered OFF when removing or installing the PCMCIA card.
4. The PCMCIA card has a capacity of 10 Megabytes which is 10 times greater than the memory of the Tech 1 Mass Storage Cartridge.
5. The Tech 2 has the capability of two snapshots.
6. The PCMCIA card is sensitive to magnetism and static electricity, so care should be taken in the handling of the card.
7. The Tech 2 can plot a graph when replaying a snapshot.
8. Always return to the Main Menu by pressing the EXIT key several times before shutting down.
9. To clear Diagnostic Trouble Codes (DTCs), open Application Menu and press “F1: Clear DTC Info”.
Getting Started
Before operating the Isuzu PCMCIA card with the Tech 2, the following steps must be performed:
1. The Isuzu 2000 Model Year System PCMCIA card (1) inserts into the Tech 2 (5).
2. Connect the SAE 16/19 adapter (3) to the DLC cable (4).
3. Connect the DLC cable to the Tech 2 (5).
4. Make sure the vehicle ignition is off.
5. Connect the Tech 2 SAE 16/19 adapter to the vehicle DLC.
6. Turn on the vehicle ignition.
7. Power the Tech 2 ON and verify the Tech 2 power up display.
TechTech
2
Press [ENTER] to continue.
Software Version: X.XXX
NOTE: The RS232 Loop back connector is only to use for diagnosis of Tech 2. Refer to user guide of the Tech 2.
5A4-12 ANTI-LOCK BRAKE SYSTEM (ABS)
Operating Procedure (For Example)
The power up screen is displayed when you power up the tester with the Isuzu systems PCMCIA card. Follow the operating procedure below.
TechTech
2
Press [ENTER] to continue.
Software Version: X.XXX
F0: Diagnostics F1: Code Index F2: View Capture Data F3: Tool Options F4: Download / Upload Help
(ENTER)
Main Menu
Vehicle Identification
Select one of the following
Vehicle Type (s)
Rodeo/Amigo, Wizard/MU
(UE)
LUV
(TF )
ELF, NPR, NQR
(N)
Industrial Engine
(Off-Road)
(N) ELF, NPR, NQR
(NENTER)
(1) 2001 (N) ELF, NPR, NQR
F0: F1: F2:
System Selection Menu
Engine Chassis Body
(F2 ENTER)
Vehicle Identification
Select one of the following
ABS
Chassis
3 / 4
(1) 2001 (Y) 2000 (X) 1999 (
W
) 1998
(1) 2001
(F0)
Vehicle Identification
Select one of the following
Model Year(s)
(2000, ENTER)
1 / 4
ABS
1 / 2
(ABS/ASR ENTER)
Menu
The following table shows which functions are used for the available equipment versions.
Chassis
(Y) 2000 (N) ELF, NPR, NQR
Electronic System: ABS
Partnumber 8972521653 Identifier 00(2WD) 20(4WD) 40(ABS/ASR) 60(12V vehicle)
Partnumer
Confirm
DTC Modes
Chassis
F0:
Diagnostic Trouble Codes
F1:
Data Display
F2: Snapshot
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-13
Diagnostic Trouble Codes
F0:
Read DTC Info Ordered By Priority
F1:
Clear DTC Information
F2: DTC Information F3: Clear & Reset Vehicle Type
The following is a brief description of each of the sub menus in DTC Info and DTC. The order in which they appear here is alphabetical and not necessarily the way they will appear on the Tech 2.
DTC Information Mode
Use the DTC info mode to search for a specific type of stored DTC information. There are two choices. The service manual may instruct the techinician to test for DTCs in a certain manner. Always follow published service procedures.
F3: Actuator Test
There are two options available in Tech 2 DTC mode to display the enhanced information available. After selecting DTC, the following menu appears.
DTC Info
Clear Info
5A4-14 ANTI-LOCK BRAKE SYSTEM (ABS)
When CODE “13” is displayed (Vehicle Type Error)
Step Action Value(s) Yes No
1 Check harness.
Is it okay?
- Erase vehicle type with TECH
Replace the
harness.
2 and reread
harness
information.
Diagnostic Trouble Codes
F0:
Read DTC Info
F1:
Clear DTC Info
F2: DTC Info
(F3: ENTER)
DTC Status
Current Diagnostic Trouble Codes
This selection will display all DTCs that have failed during the present ignition cycle.
Clear & Reset Vehicle Type
Do you want clear &
Reset V ehicle Type?
YES
NO
YES: Clear vehicle type and reread vehicle harness
information.
NO: Return
History Diagnostic Trouble Codes
This selection will display only DTCs that are stored in the EHCU’s history memory.
Plotting Snapshot Graph
This test selects several necessary items from the data list to plot graphs and makes data comparison on a long term basis. This test can check ABS performance and defect by graphing wheel speed differences between right and left sides, and front and rear sides obtained from the ABS data list menu.
For trouble diagnosis, you can collect graphic data (snap shot) directly from the vehicle.
You can replay the snapshot data as needed. Therefore, accurate diagnosis is possible, even though the vehicle is not available.
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-15
Plotting Graph Flow Chart (Plotting graph after obtaining vehicle information)
5A4-16 ANTI-LOCK BRAKE SYSTEM (ABS)
Flow Chart for Snapshot Replay (Plotting Graph)
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-17
Tech 2 Data Display
Use the Tech 2 data Values only after the ABS Diagnostic System Check has been completed, no DTC(s) were noted, and you have determined that the on-board diagnostics are functioning properly. Tech 2 values from a properly-running engine may be used for comparison with the engine you are diagnosing.
ABS Data
Ignition SW is “ON” position.
(For example)
Special Function
There are 12 different menus available for this test. The state of each circuit can be tested by using these menus. Especially when DTC cannot be detected, a faulty circuit can be diagnosed by testing each circuit by means of these menus.
Even when DTC has been detected, the circuit tests using these menus could help discriminate between a mechanical trouble and an electrical trouble.
In all cases test condition; Engine stops with the key turned to the “ON” position. To be more specific, the test is conducted with the brake pedal stepped on after stepping once and releasing.
Engine: Stop
Ignition SW: ON
Brake Pedal: ON-OFF-ON
If the Ignition SW was turned OFF or communication was lost, make sure to apply the brake pedal ON-OFF­ON once again and then continue the test.
Actuator Test
ABS Relay Test
F0:
Return Pump Relay Test
F1:
Front Left Solenoid Valve Test
F2:
Front Right Solenoid Valve Test
F3:
Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
ABS Check Light Test
F6:
Exhaust Brake Cut Test
F7:
5A4-18 ANTI-LOCK BRAKE SYSTEM (ABS)
ABS Warning Lamp
Test condition: Engine stops with the key turned to the “ON” position. To be more specific, the test is conducted with the brake pedal stepped on after stepping once and releasing.
The circuit is normal if the warning light in the meter panel comes on and goes out in accordance with Tech 2’s instruction.
Actuator Test
ABS Relay Test
F0:
Return Pump Relay Test
F1:
Front Left Solenoid Valve Test
F2:
Front Right Solenoid Valve Test
F3:
Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
Exhaust Brake Cut Test
F7:
ABS Relay
Test condition: Engine stops with the key turned to the “ON” position. To be more specific, the test is conducted with the brake pedal stepped on after stepping once and releasing.
Make sure of the working sound of the ABS relay. The circuit is normal if the working sound of the ABS
relay is made in accordance with Tech 2’s instruction.
Actuator Test
ABS Motor
Test condition: Engine stops with the key turned to the “ON” position. To be more specific, the test is conducted with the brake pedal stepped on after stepping once and releasing.
Make sure of the working sound of the ABS motor. The circuit is normal if the working sound of the ABS
motor is made in accordance with Tech 2’s instruction.
Actuator Test
F0:
ABS Relay Test
F2:
Front Left Solenoid Valve Test
F3:
Front Right Solenoid Valve Test Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
ABS Check Light Test
F6:
Exhaust Brake Cut Test
F7:
Exhaust Brake Cut Relay
Test condition: Engine stops with the key turned to the “ON” position. To be more specific, the test is conducted with the brake pedal stepped on after stepping once and releasing.
Make sure of the working sound of the exhaust brake cut relay.
The circuit is normal if the working sound of the exhaust brake cut relay is made in accordance with Tech 2’s instruction.
Return Pump Relay Test
F1:
Front Left Solenoid Valve Test
F2:
Front Right Solenoid Valve Test
F3: F4:
Rear Left Solenoid Valve Test
F5:
Rear Right Solenoid Valve Test
F6:
ABS Check Light Test
F7:
Exhaust Brake Cut Test
Actuator Test
ABS Relay Test
F0:
Return Pump Relay Test
F1:
Front Left Solenoid Valve Test
F2:
Front Right Solenoid Valve Test
F3:
Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
ABS Check Light Test
F6:
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-19
Hold Valve Test
Purpose: The purpose of this test is to detect brake pipe and valve line harness wire wrong connections and valve trouble.
This test will help you confirm the result of your repair service including the removal/reinstallation of brake pipe, valve line harness and valve.
Actuator Test
ABS Relay Test
F0:
Return Pump Relay Test
F1:
Front Right Solenoid Valve Test
F3:
Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
ABS Check Light Test
F6:
Exhaust Brake Cut Test
F7:
Test conditions: The ignition key is the “ON” position with the four wheels lifted up. The brake pedal is stepped on, released and stepped on again with the parking brake released.
Test procedure:
1. Connect Tech 2 with the vehicle, and select Special Function from the menus.
2. Select a Hold Valve Menu from the Special Function Menus.
Actuator Test
ABS Relay Test
F0:
Return Pump Relay Test
F1:
Front Right Solenoid Valve Test
F3:
Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
ABS Check Light Test
F6:
Exhaust Brake Cut Test
F7:
Select a Iso Solenoid from the Front Left Solenoid Valve Test Function Menus.
Front Left Solenoid Valve Test
Dump Solenoid
3. Press the Hold Valve “ON” Soft Key with the brake pedal stepped on.
4. Release the brake pedal.
5. Make sure that the Hold Valve “ON” aimed at by Tech 2 and the wheel locked position are the same. If different, check brake pipe, valve line harness wiring and H/UNIT. Repair is needed if abnormality is found.
6. Conduct Step 2 through Step 5 above on all the four wheels.
CAUTION: When conducting this test, please observe the following cautions.
1. Do not start the engine without fail.
2. Lift up the vehicle at the level floor.
•••• Secure a clearance from the floor surface
enough to allow the lifted tire to rotate.
3. Maintain the lift up.
4. Wipe the floor surface to remove water and oil so that the surface may become unslippery.
5. Do not load the vehicle.
•••• When lifting up the vehicle, be sure to
observe the lifting up points. Refer to vehicle lifting points in 0A section.
5A4-20 ANTI-LOCK BRAKE SYSTEM (ABS)
Release Valve Test
Purpose: The purpose of this test is to detect brake pipe and valve line harness wire wrong connections and valve trouble.
This test will help you confirm the result of your repair service including the removal/reinstallation of brake pipe, valve line harness and valve.
Actuator Test
ABS Relay Test
F0:
Return Pump Relay Test
F1:
Front Right Solenoid Valve Test
F3:
Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
ABS Check Light Test
F6:
Exhaust Brake Cut Test
F7:
Test conditions: The ignition key is in the “ON” position with the four wheels lifted up. The brake pedal is stepped on, released and stepped on again with the parking brake released.
Select a Dump Solenoid from the Front Left Solenoid Valve Test Function Menus.
Front Left Solenoid Valve Test
Iso Solenoid
3. Press the Release Valve “ON” Soft Key with the brake pedal stepped on.
4. Make sure that the Release Valve “ON” aimed at by Tech 2 and the wheel released position are the same. If different, check brake pipe, valve line harness wiring and H/UNIT. Repair is needed if abnormality is found.
5. Conduct Step 2 through Step 5 above on all the four wheels.
Test procedure:
1. Connect Tech 2 with the vehicle, and select Special Function from the menus.
2. Select a Release Valve Menu from the Special Function Menus.
Actuator Test
ABS Relay Test
F0:
Return Pump Relay Test
F1:
Front Right Solenoid Valve Test
F3:
Rear Left Solenoid Valve Test
F4:
Rear Right Solenoid Valve Test
F5:
ABS Check Light Test
F6:
Exhaust Brake Cut Test
F7:
CAUTION: When conducting this test, please observe the following cautions.
1. Do not start the engine without fail.
2. Lift up the vehicle at the level floor.
•••• Secure a clearance from the floor surface
enough to allow the lifted tire to rotate.
3. Maintain the lift up.
4. Wipe the floor surface to remove water and oil so that the surface may become unslippery.
5. Do not load the vehicle.
•••• When lifting up the vehicle, be sure to
observe the lifting up points. Refer to vehicle lifting points in 0A section.
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-21
EHCU Connector Pin-out Checks
Disconnect EHCU.
Key
No. Circuit to be Tested
1 EHCU Power Circuit OFF VDC 3(+)-1(-) 0-0.3V
2 EHCU Ground Circuit OFF 1(+)-GND Less than 0.01
3 EXHIN Circuit ON VDC 7(+)-1(-) 9.5-16.5V
4 EXHOUT Circuit ON VDC 8(+)-1(-) 9.5-16.5V
5 Brake Switch Signal
Circuit
6 ABS W/L Circuit ON VDC 6(+)-1(-) 9.5-16.5V
7 FL Speed Sensor OFF k 10(+)-11(-) 1-2kΩ
8 FR Speed Sensor OFF k 32(+)-33(-) 1-2kΩ
Switch
Position
ON VDC 3(+)-1(-) 9.5-16.5V
OFF VDC 2(+)-1(-) 9.5-16.5V
OFF VDC 24(+)-1(-) 9.5-16.5V
OFF 23(+)-GND Less than 0.01 Ω
OFF VDC 8(+)-1(-) 0-0.3V OFF VDC 16(+)-1(-) 0-0.3V
OFF VDC 16(+)-1(-) 9.5-16.5V
OFF VDC 6(+)-1(-) 0-0.3V
OFF k 10(+)-1(-) More than
OFF VDC 10(+)-11(-) More than 200mV Turn Wheel at
OFF k 32(+)-1(-) More than
OFF VDC 32(+)-33(-) More than 200mV Turn Wheel at
Multimeter
Scale/Range
Perform checks with high impedance digital multimeter 5-8840-0285-0 (J-39200) or equivalent.
Measure
between Pin
Nominal Value
(24V Battery
Vehicle)
(16.5-34V)
(16.5-34V)
(16.5-34V)
(16.5-34V)
(16.5-34V)
(16.5-34V)
(16.5-34V)
1000k
1000k
Note
Engine Run
Apply Brake Pedal
0.5RPS
0.5RPS
5A4-22 ANTI-LOCK BRAKE SYSTEM (ABS)
Circuit Diagram-FOR 12VOLT
FL-4 ABS
60A
FL-1
MAIN
80A
8B 8W
3R
2
H-6
RELAY;
CHARGE
5W5W3W
0.5W/L
3W 0.5G/Y
RELAY ;
EXH.BRAKE
1
B-38
2
B-38
B-38
B-38
2B/R
5
4
F-17
STOP LAMP
10A
F-14
EXH.BRAKE
15A
H-5
SW ; STOP LAMP
1
B-66
3R
40
B-66
2
0.5G
0.5LG
P-1
BATTERY
P-2
P-5
3W/B
H-7
FL-2
KEY SW
50A
1
3W/B
0.3B
RELAY ; EXH.B/CUT
0.3B
0.5B/Y
0.5B/Y
J-50
J-50
0.5B/G
J-18
J-18
2B
GAUGE
BACK
2
1
4
2
(ABS)
F-12
10A
0.5B/Y
0.5B/Y
SW ; EXH.BRAKE
J-18
3
0.5LG/B
H-5
12
H-8
17
5
0.5LG/R
J-18
0.5LG/B 0.5LG/R
0.3B
KEY SW
OFF
2
B
B-67
0.3B 0.5B
ACC
ON ST
SW ; NEUTRAL
(Neutral=ON)
RELAY ; EXH.BRAKE CONTROL
B-67
3B/Y
3
0.5LG/W
J-163J-161J-16
J-16
5
0.5LG/B0.5LG/B0.5LG/L
H-5
36
5
B-69
B-69
3
1
B-89
2
J-16
4
0.3B 0.3B
1
0.5LG/L0.5LG/L
SW ; CLUTCH
0.5B
8
B-51
IND.LAMP ;
EXH.BRAKE
B-51
B-89
RELAY ; TAIL
0.5LG/R
0.5LG/B
0.3B
METER
0.5B/Y
B-52
2
ABS
10
0.85B
2
B-31
3
B-31
1
B-31
B-51
1
SW ; ENG.WARMING
0.5B/Y
0.5LG/B
7
0.5W
3
B-35
B-355B-35
0.5B
B-18
B-18
B-31
B-31
B-31
3
5
6
4
0.3W/V
B-35
0.5BR/B
DIODE
B-18
0.3B
0.5BR/R
0.5BR/R
4
2
2
RELAY ; ABS IND.
0.5LG/W
FRAME-LH (FRONT)
HEADLIGHT BRACKET (LH)
FRAME-LH (CENTER)
2B
B-1 B-7
J-9
8
3B 3B
2
JOINT
B-29
7
CONNECTOR 3B 3B 2B 2B 2B
0.85B 3B
3B
0.5B
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-23
0.5G
3R
0.5LG
15
H-8
0.5BR/R
H-14
10
0.5BR/R
2
E-9
E-9
1
0.5BR/R
SW ; THERMO (ENG.WARM)
11
0.5LG/B
0.3W/V
0.5B/Y
9
H-14
H-5
STOP LAMP
(LH)
22
34
32
33
10
11
21
12
29
4
0.5G
0.5G
0.5L
0.5Y
0.5V
0.5R/B
0.5P
0.5L
0.5R
0.5W
0.3W/B
0.3W/G
0.5G
STOP LAMP
(RH)
33
H-5
34
H-5
ALDL
B-79
CONNECTOR
16 15 14 13 12 11 10 9
8 7 6 5 4 3 2 1
2
1
1
2
1
2
4
3
J-78
J-78
J-75
J-75
J-74
J-74
J-78
J-78
0.3W/G
0.5B
0.5B
SPEED SENSOR (RR,LH)
SPEED SENSOR (FRT,LH)
SPEED SENSOR (FRT,RH)
SPEED SENSOR (RR,RH)
0.3W/B
0.5G
0.5G
16
3R
3R
3B
3B
35
H-5
3B
0.5BR/B0.5BR/B
16
H-8
24
2
23
1
8
7
6
3
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
2
EHCU ; ABS
STOP LAMP
MOTOR +B
VALVE +B
MOTOR GND
VALVE GND
EXH.B/CUT OUT
EXH.B/CUT IN
IND.
IG
MODE1
MODE2
MODE3
H-16
RL 12V
RL SIG
FL SIG
FL GRD
FR SIG
FR GRD
RR 12V
RR SIG
J1850
FRASH
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
0.5LG/W
0.5BR/B
SW ; ACCEL
2
B-75
B-75
3B 3B 2B
1
0.5LG
32
H-5
0.5LG
0.5LG0.5B
J-31
J-31
1
2
0.5BR/B
0.5LG
MAG.VALVE ; EXH.BRAKE
2B
J-40
J-40
0.5B
1
2
VSV ; INT.THROTTLE
0.5B
J-23
J-23
J-41
J-41
0.5L
0.5B
3
2
1
2
DIODE ; FICD
J-23
VSV ; FICD
0.5G/O
1
3B
A/C COMPRESSOR
5A4-24 ANTI-LOCK BRAKE SYSTEM (ABS)
Circuit Diagram-FOR 24VOLT
FL-4 ABS
40A
FL-1
MAIN
60A
8B 8W
3R
2
H-6
RELAY;
CHARGE
5W 3W
0.5W/R
5W 0.5G/Y
RELAY ;
EXH.BRAKE
1
B-38
2
B-38
B-38
B-38
F-10
STOP LAMP
10A
F-14
EXH.BRAKE
10A
2B/R 0.5LG/W
5
4
H-8
SW ; STOP LAMP
1
B-66
3R
8
B-66
2
0.5G
0.5LG
P-1
BATTERY
P-2
P-3
BATTERY
P-4
P-5
3W/B
H-7
FL-2
KEY SW
60A
1
3W/B
RELAY ; EXH.B/CUT
0.3B
0.5B/Y
0.5B/Y
H-14
0.5P0.5B0.5B/G
E-11
E-11
H-14
J-18
J-18
0.5B
GAUGE
BACK
5 2
1
10
4
2
(ABS)
F-12
10A
0.5B/Y
0.5B/Y
SW ; EXH.BRAKE
J-18
3
0.5LG/B
17
H-8
0.5LG/B 0.5LG/R
0.3B
KEY SW
OFF
2
0.3B
B
B-67
0.3B 0.5B
ACC
ON
ST
SW ; NEUTRAL
(Neutral=ON)
RELAY ; EXH.BRAKE CONTROL
B-67
3B/Y
3
J-163J-161J-16
H-5
38
5
0.5LG/R
J-18
1
0.5LG/W
J-16
0.5LG/B
H-8
B-69
B-69
B-89
J-16
5
0.3B
6
5
3
0.5LG/R0.5LG/R
SW ; CLUTCH
2
4
8
B-51
B-89
RELAY ; TAIL
0.5B
8
B-51
IND.LAMP ;
EXH.BRAKE
2
0.5LG/R
0.5LG/B
0.3B
METER
0.5B/Y
0.5B
B-52
ABS
10
0.85B
2
B-31
3
B-31
1
B-31
B-51
A/C COMPRESSOR
3
SW ; ENG.WARMING
0.5B/Y
0.5LG/B
7
0.5W
3
B-35
B-355B-35
0.5B
B-18
B-18
B-31
B-31
B-31
0.5G/O
0.5BR/R
1
5
6
4
0.3W/V
B-35
DIODE
B-18
0.3B
0.5BR/B
0.5BR/B
4
2
0.5BR/R
39
H-5
2
RELAY ; ABS IND.
0.5LG/W
FRAME-LH (FRONT)
HEADLIGHT BRACKET (LH)
FRAME-LH (CENTER)
2B
B-1 B-7
J-9
8
3B 3B
2
JOINT
B-29
7
CONNECTOR 3B 3B 2B 2B 2B
0.85B 3B
3B
0.5B
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-25
RELAY ;
CERAMIC
HEATER
0.5LG/W
1
J-15
J-23
0.5G
3R
0.5LG
0.5BR
0.5BR/B
11
H-8
0.5BR/B
J-155J-15
1
0.5BR/R
1
B-75
0.5BR/R
1
E-86
J-15
SW ; ACCEL
4
J-23
J-23
2
0.5L/G0.5L/G
2
H-13
11
H-5
THERMO SW ;
ENG.WARMING
0.5LG/B
0.3W/V
5
0.5B/Y
4
RELAY ; ENG.WARMING CUT
2
0.5BR/W
B-75
DIODE ; FICD
3
J-23
E-86
H-8
2
0.5L/W
2
H-200
18
32
0.5BR/B0.5BR/B
2
H-5
H-5
H-5
0.5G
0.5G
3R
3B
3B
3B
0.5B/Y(NQR)
0.5B/Y(NQR)
0.5B/Y(NQR)
0.5BR/W
0.5LG 0.5LG
37
0.5L/W
0.5LG0.5B
2
H-16
EHCU ; ABS
16
J-500
STOP LAMP
24
J-500
MOTOR +B
2
J-500
VALVE +B
23
J-500
MOTOR GND
1
J-500
VALVE GND
8
J-500
EXH.B/CUT OUT
7
J-500
EXH.B/CUT IN
6
J-500
IND.
3
J-500
IG
15
J-500
MODE1
14
J-500
MODE2
17
J-500
MODE3
C/U ; ENGINE
21
B-233
QWS
14
B-233
EXH.BRAKE
15
B-234
FICD
0.5LG
CHECKER
RL 12V
RL SIG
FL SIG
FL GRD
FR SIG
FR GRD
RR 12V
RR SIG
J1850
FRASH
DIAG
H-13
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
J-500
B-234
B-234
6
0.5G
0.5G
STOP LAMP
(LH)
22
0.5L
0.5Y
34
32
0.5V
0.5R/B
33
10
0.5P
0.5L
11
21
0.5R
12
0.5W
0.3W/B
29
0.3W/G 0.3W/G
4
0.3Y
14
0.3L
29
0.5G
STOP LAMP
(RH)
33
H-5
34
H-5
ALDL
B-79
CONNECTOR
16 15 14 13 12 11 10 9
2
J-149
1
J-149
1
J-75
2
J-75
1
J-74
2
J-74
2
J-148
1
J-148
8 7 6 5 4 3 2 1
0.5B
0.5B
SPEED SENSOR (RR,LH)
SPEED SENSOR (FRT,LH)
SPEED SENSOR (FRT,RH)
SPEED SENSOR (RR,RH)
0.3W/B
EX-1
EX-1
H-13
0.5B
4
VSV ; FICD
2
12
0.5B 3B 3B
0.5B
J-31
J-31
1
MAG.VALVE ; EXH.BRAKE
2
EX-3
EX-3
0.5B
1
2
VSV ; INT.THROTTLE
3B
5A4-26 ANTI-LOCK BRAKE SYSTEM (ABS)
Connector List
Connector List
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-27
5A4-28 ANTI-LOCK BRAKE SYSTEM (ABS)
Connector List
Part Location
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-29
FUSE BOX ASM F-12,F-14,F-17 (12V) F-10,F-12,F-14 (24V)
B-233,B-234 ECU (24V)
B-29 JOINT CONNECTOR
H-5
~
H-8
J-74 F/RH SENSOR
B-66 STOPLIGHT SW
(BRAKE SW)
B-1 EARTH ; FRAME (FR)
B-67 IGNITION SW "A"
STARTER SW
B-35,B-38 RELAY BOX
B-7 EARTH ; HEADLIGHT B/T
J-148 R/RH
RELAY BOX ASM J-15 (24V),J-16,J-18 RELAY B-17,B-18,J-23 DIODE FL-1,FL-2,FL-4 FUSIBLE LINK
(12V)
J-9 EARTH ; FRAME
B-79 ALDL CONNECTOR
J-75 F/LH SENSOR
B-51 ABS WARNING LIGHT (METER)
SENSOR (24V)
(24V)
J-149 R/LH SENSOR (24V)
J-78 R/RH,R/LH SENSOR (12V)
H-16
J-500 ABS EHCU
BATTERY
5A4-30 ANTI-LOCK BRAKE SYSTEM (ABS)
Symptom Diagnosis
The symptoms that cannot be indicated by the warning light can be divided in the following five categories:
1. ABS works frequently but vehicle does not decelerate.
2. Uneven braking occurs while ABS works.
3. The wheels lock during braking.
4. Brake pedal feel is abnormal
SymptomNo.
1 ABS works frequently but vehicle does not decelerate. Chart A-1 Chart TA-1 2 Uneven braking occurs while ABS works. Chart A-2 Chart TA-2 3 The wheels are locked. Chart A-3 Chart TA-3 4 Brake pedal feel is abnormal. Chart A-4 ­5 Braking sound (from Hydraulic Unit) is heard while not
braking.
5. Braking sound (from Hydraulic Unit) is heard while not braking.
These are all attributable to problems which cannot be detected by EHCU self-diagnosis. Use the customer complaint and a test to determine which symptom is present. Then follow the appropriate flow chart listed below.
Diagnostic Flow Charts
Without TECH 2 With TECH 2
Chart A-5 Chart TA-5
Chart A-1 ABS Works Frequently But Vehicle Does Not Decelerate
Step Action Yes No
1 Is braking force distribution normal between the front and
rear of the vehicle?
2 Are axle parts installed normally? Go to Step 3 Repair axle parts.
3 Is there play in each wheel speed sensor? Go to Step 4 Repair wheel
4 Is there damage, or powdered iron sticking to each wheel
speed sensor/sensor rotor?
5 Is the output of each wheel speed sensor normal? (Refer to
chart C-1 or TC-1)
6 Reconnect all components and ensure all components are
properly mounted. Was this step finished?
Go to Step 2 Repair brake parts.
Go to Step 6
Go to Step 6
speed sensor.
Go to Step 6
Go to Step 5 Replace sensor or
sensor rotor. Go to Step 6
Replace EHCU.
Go to Step 6
Repeat the “Basic
diagnostic flow
chart.”
Replace wheel
speed sensor or
repair harness.
Go to Step 6 Go to Step 6
Chart TA-1 ABS Works Frequently But Vehicle Does Not Decelerate (Use TECH 2)
Step Action Yes No
1 1. Connect TECH 2.
2. WHEEL SENSORS make sure of the output conditions of each sensor.
Is the output of each sensor normal?
2 Return to Chart A-1.
Was the Chart A-1 finished?
3 Reconnect all components, ensure all components are
properly mounted. Was this step finished?
Go to Step 2 Replace wheel
speed sensor.
Go to Step 3
Go to Step 3 Go to Step 2
Repeat the “Basic
diagnostic flow
chart.”
Go to Step 3
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-31
Chart A-2 Uneven Braking Occurs While ABS Works
Step Action Yes No
1 Is there play in each sensor? Go to Step 2 Repair.
Go to Step 5
2 Damage or powdered iron sticking to each sensor/sensor
rotor?
3 Is the output of each sensor normal? (Refer to chart C-1 or
TC-1)
4 Is brake pipe connecting order correct? Replace EHCU.
5 Reconnect all components, ensure all components are
properly mounted. Was this step finished?
Go to Step 3 Repair.
Go to Step 5
Go to Step 4 Replace sensor or
repair harness.
Go to Step 5
Reconnect brake
Go to Step 5
Repeat the “Basic
diagnostic flow
chart.”
pipe correctly.
Go to Step 5 Go to Step 5
Chart A-3, TA-3 The Wheels Are Locked
Step Action Yes No
1 Is ABS working? Go to Step 2 Go to Step 4 2 Is vehicle speed under 10 km/h (6mph)? Go to Step 3 Normal. 3 Is sensor output normal? (Chart C-1 or TC-1) Go to Step 4 Replace sensor or
repair harness.
Go to Step 5
4 Is hydraulic unit grounded properly? Replace hydraulic
unit.
Go to Step 5
5 Reconnect all components, ensure all components are
properly mounted. Was this step finished?
Repeat the “Basic
diagnostic flow
chart.”
Correct.
Go to Step 5
Go to Step 5
5A4-32 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart A-4 Brake Pedal Feed Is Abnormal
Step Action Yes No
1 Is the stop light actuated when the brake pedal is depressed? Go to Step 2 Go to Step 3 2 1. Turn the key off.
2. Disconnect EHCU connector.
3. Measure the voltage between J-500 EHCU connector terminals 16 and 1, when brake pedal is depressed.
Is the voltage between 9 - 16 V?
3 Is stop light fuse 12V: F-17, 24V: F-10 normal? Go to Step 5 Replace fuse
4 Is there continuity between J-500 EHCU connector terminal 1
to body ground?
5 Is the brake SW normal? Repair stop light
6 Is the check harness/connector for suspended
disconnection?
7 Reconnect all components, ensure all components are
properly mounted. Was this step finished?
Go to Step 4 Harness NG
between brake SW
and EHCU.
Go to Step 7
12V: F-17, 24V: F-10.
Go to Step 7
Go to Step 6 Repair body
grounded harness.
Go to Step 7
Replace brake
harness.
Go to Step 7
Hydraulic system
leakage or air entry
Go to Step 7
Repeat the “Basic
and diagnostic flow
chart.”
Go to Step 7
Repair harness.
Go to Step 7
Go to Step 7
SW.
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-33
Chart A-5, TA-5 Braking Sound (From Hydraulic Unit) Is Heard While Not Braking
Step Action Yes No
1 Is this the first time the vehicle is being driven after starting
the engine?
2 Is vehicle speed under 10 km/h (6 mph)? It is self checking
3 Check for the following condition:
At the time of shift down or clutch operation.
At the time of low µ drive (ice or snow road) or rough road
drive.
At the time of high-speed turn.
At the time of passing curb.
At the time of operating electrical equipment switches.
At the time of racing the engine.
Did it occur under any one condition above?
4 Is there play in each sensor/wheel speed sensor rotor? Go to Step 5 Repair.
5 Damage or powdered iron sticking to each sensor/wheel
speed sensor rotor?
6 Is each sensor output normal? (Refer to chart C-1 or TC-1). Check
7 Reconnect all components, ensure all components are
properly mounted. Was this step finished?
It is self checking
sound.
Normal.
sound.
Normal.
ABS may
sometime be
actuated even
when brake pedal
is not applied.
Repair.
Go to Step 7
harness/connector
for suspected
disconnection.
If no disconnection
is found, replace
EHCU.
Go to Step 7
Repeat the “Basic
diagnostic flow
chart.”
Go to Step 2
Go to Step 3
Go to Step 4
Go to Step 7 Go to Step 6
Repair.
Go to Step 7
Go to Step 7
5A4-34 ANTI-LOCK BRAKE SYSTEM (ABS)
Diagnostic Trouble Codes
Choose and trace an appropriate flowchart by the numbers listed below to find fault and repair.
Code
Flash
out
12 - Normal - ­13 C0213 Vehicle Type Error EHCU 1 14 C0214 Low Power Voltage of Rear Sensor or ECU
15 C0215 Low Power Voltage EHCU 3 25 C0225 Exhaust Brake Cut Circuit Abnormality Relay or EHCU 4 33 C0233 Motor Drive Circuit Abnormality EHCU 5 34 C0234 Abnormal Motor Rotation EHCU 6 41 C0241 Solenoid Valve Power Supply Abnormality EHCU 7 43 C0243 Solenoid Valve Circuit Abnormality 45 C0245 Solenoid Valve Circuit Abnormality 51 C0251 FL Speed Sensor Circuit Abnormality 9 52 C0252 FR Speed Sensor Circuit Abnormality 10 53 C0253 RL Speed Sensor Circuit Abnormality 11 54 C0254 RR Speed Sensor Circuit Abnormality 12 61 C0261 Abnormal FL Speed Sensor Signal 13 62 C0262 Abnormal FR Speed Sensor Signal 14 63 C0263 Abnormal RL Speed Sensor Signal 15 64 C0264 Abnormal RR Speed Sensor Signal 16 65 C0265 Tire Size Error Tire, Sensor, EHCU 17
* Important: DTC 20 (Reference Voltage High) cannot be indicated by Tech 2. DTC 20 can be indicated and
confirmed by flashing using Diagnosis Switch.
Serial
Communications
Diagnosis Chart No.
Abnormality
Item (except
Wiring)
2EHCU
8EHCU
Sensor, EHCU
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-35
Diagnosis BY “ABS” Warning Light Illumination Pattern
In the event that there is abnormality in the “ABS” warning light illumination pattern while the key is in the
No. Condition “ABS” Warning Light Illumination Pattern Diagnostic
1 Warning light is
actuated normally
2 Warning light is not lit Warning light lighting circuit
3 Warning light is
actuated while driving
ON position or if the warning light is actuated during driving, trouble should be diagnosed on a illumination pattern basis as follows:
Normal
troubleGo to Chart B-1
Diagnostic trouble codes are stored.
Display diagnostic trouble codes and diagnose on a code basis according to the flow charts.
Diagnostic Trouble Codes (DTCs)
When the warning light in the meter remains ON, the EHCU stores the fault identification and disables the ABS.
1. How to start DTC display:
Confirm that the vehicle has come to a complete stop (with the wheels standing still) and that the brake pedal is not depressed. (Unless these two conditions are satisfied, DTC display cannot be started.)
With the key switch OFF and short B-79 diagnosis connector terminal 12 to ground. Then turn the key switch ON.
DTCs can be displayed also by TECH 2.
5A4-36 ANTI-LOCK BRAKE SYSTEM (ABS)
The DLC (for Tech 2) is located behind the driver side lower cluster panel
2. DTC display:
DTC is displayed by blinking warning light.
Double-digit display.
First, normal DTC 12 is displayed three times
and then any other DTCs are displayed three times. (If no other DTCs have been stored, the display of DTC 12 will be repeated.)
3. How to erase code:
Conduct brake switch ON/OFF operation 6 or more times within 3 seconds of self-diagnosis startup.
The code cannot be erased if more than 3 seconds have passed since self-diagnosis startup, or if self-diagnosis has started with brake switched on (brake pedal depressed).
DTCs can be erased also by Tech 2.
4. An example of DTC display Display of DTC 23
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-37
After displaying DTC 12 three times, one DTC after another is displayed, starting with the most recent one. (However, display is discontinued after about 5 minutes.)
The DTC 12 is displayed repeatedly. (display is discontinued after about 5 minutes)
5A4-38 ANTI-LOCK BRAKE SYSTEM (ABS)
5. How to display vehicle model:
1) Turn the key switch OFF.
2) Short the diagnosis connector terminal 12 to
ground.
3) Slightly push the brake pedal.
4) Turn the key switch ON.
5) ABS warning light illuminates.
6) Illuminating number of times indicates the vehicle model.
Vehicle model Illuminating number of times
NKR, NPR 1
NQR 8
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-39
Chart B-1-1 With the key in the ON position (Before starting the engine). Warning light (W/L) is not activated.
Step Action Value(s) Yes No
1 Is W/L fuse F-12 disconnected? - Go to Step 5 Go to Step 2 2 Is W/L burnt out? - Go to Step 6 Go to Step 3 3 1. Turn the key off.
2. Disconnect EHCU connectors.
3. Turn the key on.
4. Using DVM, measure the voltage between J-500 EHCU connector terminals 6 and 1.
Does the DVM display a voltage within the specified value?
4 Check the continuity between J-500 EHCU
connector terminal 1 and body ground. Is there continuity?
5 Replace the fuse.
Is action complete?
6 Replace the W/L bulb.
Is action complete?
7 Locate and repair open circuit, poor connection
or short circuit in the ignition feed circuit. Is action complete?
8 Locate and repair open circuit, poor connection
or short circuit in the ground circuit. Is action complete?
9 1. Check the harness for suspected
disconnection.
2. If no fault found, replace the EHCU.
Is action complete?
10 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
12V: 9.5-16.5V
24V: 16.5-34V
- Go to Step 9 Go to Step 8
- Go to Step 10 -
- Go to Step 10 -
- Go to Step 10 -
- Go to Step 10 -
- Go to Step 10 -
- Go to “Basic
Go to Step 4 Go to Step 7
-
diagnostic flow
chart.”
5A4-40 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart 1 (DTC13/C0213) Vehicle Type Error
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Turn the key on.
3. Measure the voltage at terminal 14, 15, and 17.
2 1. Turn the key off and connect EHCU.
2. Connect the TECH 2.
3. Clear the vehicle type.
4. Does the warning light turn off?
3 Confirm the vehicle type.
Is the vehicle type okay?
4 Clear the DTC. - Troubleshooting
5 Repair harness.
Does the warning light turn off?
NQR:
All terminal
battery voltage
NKR, NPR:
All terminal 0V
- Go to Step 3 Replace the
- Go to Step 4 Replace the
- Go to Step 3 Replace the
Go to Step 2 Go to Step 5
Go to Step 3
Repeat Step 3
completed.
Go to Step 3
EHCU.
EHCU.
-
EHCU.
Chart 2 (DTC14/C0214) Low Power Voltage of Rear Sensor or EHCU Abnormality
Step Action Value(s) Yes No
1 Perform chart 11 and 12. - Go to Step 2 Go to Step 1 2 1. Turn the key off.
2. Disconnect the EHCU connector.
3. Measure continuity between the body ground and J-500 connector terminal 1, 23. Is there continuity?
3 1. Connect the EHCU connector.
2. Clear DTC.
3. Turn the key from off to on and perform diagnosis procedure. Does the DTC repeat?
4 Repair the open/short circuit or malfunction at
connection of connector. Is this step completed?
5 Replace the EHCU.
Is this step completed?
6 1. Install all parts. Verify each part is properly
installed.
2. Clear DTC. Is this step completed?
- Go to Step 3 Go to Step 4
- Go to Step 5 Go to Step 6
- Go to Step 6 -
- Go to Step 6 -
- Go to “Basic diagnostic flow
chart”.
Go to Step 6
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-41
Chart 3 (DTC15/C0215) EHCU Voltage OUT of Range
Step Action Value(s) Yes No
1 Is the battery voltage okay? - Go to Step 2 Go to Step 5 2 1. Turn the key off.
2. Disconnect the EHCU connector.
3. Start the engine.
4. Measure voltage between J-500 connector terminal 2 and J-500 connector terminal 1,
23. Is the voltage within the specified value?
3 Locate the malfunction of connection in the
circuit. Is the circuit malfunction specified?
4 Repair the malfunction and perform diagnosis
procedure. Does the DTC repeat?
5 Charge or replace the battery.
Is this step completed?
6 Repair open/short circuit or malfunction at
connection of connector between J-500 connector terminal 2 and fusible link FL-4. Is this step completed?
7 Replace the EHCU.
Is this step completed?
8 1. Install all parts. Verify each part is properly
installed.
2. Clear DTC. Is this step completed?
12 V vehicle:
10-16 V
24 V vehicle:
17-33.5 V
- Go to Step 4 Go to Step 8
- Go to Step 7 Go to Step 8
- Go to Step 8 -
- Go to Step 8 -
- Go to Step 8 -
- Go to “Basic
Go to Step 3 Go to Step 6
Go to Step 8
diagnostec flow
chart”.
5A4-42 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart 4 (DTC25/C0225) Exhaust Brake Cut Circuit Abnormality
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Start the engine.
3. Measure voltage between EHCU terminals 8 and 1.
Is the voltage within the specified value?
2 Measure voltage between EHCU terminals 7
and 1. Is the voltage within the specified value?
3 Short EHCU terminal 8 to 1.
Is the voltage at EHCU terminal 7 less than 1.5 V?
4 Measure resistance of the exhaust brake cut
relay coil.
5 Measure voltage at coil power side of relay box
connector. (key at on position) Is the voltage within the specified value?
6 Turn the exhaust brake switch on.
Does the exhaust brake indicator light turn on?
12 V vehicle:
More than 5 V
24 V vehicle:
More than 10 V
12 V vehicle:
More than 5 V
24 V vehicle:
More than 10 V
- Replace the
12 V vehicle: 60-120 ohms
24 V vehicle:
210-310 ohms
12 V vehicle:
10-16 V
24 V vehicle:
20-32 V
- Repair harness
Go to Step 2 Go to Step 4
Go to Step 3 Go to Step 6
Replace the
EHCU.
Go to Step 5 Replace the
Check harness
between EHCU
terminal 8 and exhaust brake
cut relay.
Repair as
necessary.
of EHCU
terminal 7.
exhaust brake
cut relay.
exhaust brake
cut relay.
Repair harness
and/or power
Go to exhaust
brake diagnosis
procedure.
line.
Chart 5 (DTC33/C0233) Motor Drive Circuit Abnormality
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Measure voltage between EHCU terminals 24 and 1.
Is the voltage within the specified value?
2 Measure continuity between EHCU terminals
23 and 1. Is there continuity?
3 Check the ABS fusible link (12V: 60A, 24V:
40A). Is it okay?
12 V vehicle:
10-16 V
24 V vehicle:
20-32 V
- Replace the
- Repair the
Go to Step 2 Go to Step 3
Repair the
EHCU.
harness.
harness.
Replace the
ABS fusible link
(12V: 60A, 24V: 40A).
Chart 6 (DTC 34/C0234) Abnormal Motor Rotation
Replace EHCU.
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-43
Chart 7 (DTC41/C0241) Solenoid Valve Power Supply Abnormality
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Measure voltage between EHCU terminals 2 and 1.
Is the voltage within the specified value?
2 Check the ABS fusible link (12V: 60A, 24V:
40A). Is it okay?
12 V vehicle:
10-16 V
24 V vehicle:
20-32 V
- Repair the
Replace the
EHCU.
harness.
Go to Step 2
Replace the
ABS fusible link
(12V: 60A, 24V: 40A).
Chart 8 (DTC 43, 45/C0243, C0245) Solenoid Valve Circuit Abnormality
Replace EHCU.
Chart 9 (DTC51/C0251) FL Speed Sensor Circuit Abnormality
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Measure resistance between EHCU terminals 32 and 33.
Is the resistance within the specified value?
2 1. Disconnect the FL speed sensor
connector.
2. Measure the FL speed sensor resistance.
Is the resistance okay?
1-2 k ohms Replace the
EHCU.
- Repair the harness.
Go to Step 2
Replace the FL
speed sensor.
Chart 10 (DTC52/C0252) FR Speed Sensor Circuit Abnormality
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Measure resistance between EHCU terminals 10 and 11.
Is the resistance within the specified value?
2 1. Disconnect the FR speed sensor
connector.
2. Measure the FR speed sensor resistance.
Is the resistance okay?
1-2 k ohms Replace the
EHCU.
- Repair the harness.
Go to Step 2
Replace the FR
speed sensor.
5A4-44 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart 11 (DTC53/C0253) RL Speed Sensor Circuit Abnormality
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Disconnect RL speed sensor connector.
3. Measure continuity between EHCU terminal 22 and positive side of chassis harness connector connected to RL speed sensor.
Is there continuity?
2 Measure continuity between EHCU terminals
22 and 1. Is there continuity?
3 1. Start the engine.
2. Measure voltage between EHCU terminals 22 and 1.
Is the voltage within the specified value?
4 Measure continuity between EHCU terminal 34
and positive side of chassis harness connector connected to RL speed sensor.
Is there continuity?
5 Measure continuity between EHCU terminals
34 and 1. Is there continuity?
6 1. Start the engine.
2. Measure voltage between EHCU terminals 34 and 1.
Is the voltage within the specified value?
7 Check the RL speed sensor (Refer to chart C-
1-3 or TC-1). Does the DVM display a voltage within the specified value?
- Go to Step 2 Repair the harness.
- Go to Step 3 Repair the harness.
Less than 2 V Go to Step 4 Repair the
harness.
- Go to Step 5 Repair the harness.
- Go to Step 6 Repair the harness.
Less than 2 V Go to Step 7 Repair the
harness.
0.2-4.5 V Replace the EHCU.
Replace the RL
speed sensor.
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-45
Chart 12 (DTC54/C0254) RR Speed Sensor Circuit Abnormality
Step Action Value(s) Yes No
1 1. Disconnect EHCU connector.
2. Disconnect RR speed sensor connector.
3. Measure continuity between EHCU terminal 21 and positive side of chassis harness connector connected to RR speed sensor.
Is there continuity?
2 Measure continuity between EHCU terminals
21 and 1. Is there continuity?
3 1. Start the engine.
2. Measure voltage between EHCU terminals 21 and 1.
Is the voltage within the specified value?
4 Measure continuity between EHCU terminal 12
and positive side of chassis harness connector connected to RR speed sensor.
Is there continuity?
5 Measure continuity between EHCU terminals
12 and 1. Is there continuity?
6 1. Start the engine.
2. Measure voltage between EHCU terminals 12 and 1.
Is the voltage within the specified value?
7 Check the RR speed sensor (Refer to chart c-
1-4 or TC-1). Does the DVM display a voltage within the specified value?
- Go to Step 2 Repair the harness.
- Go to Step 3 Repair the harness.
Less than 2 V Go to Step 4 Repair the
harness.
- Go to Step 5 Repair the harness.
- Go to Step 6 Repair the harness.
Less than 2 V Go to Step 7 Repair the
harness.
0.2-4.5 V Replace the EHCU.
Replace the RR
speed sensor.
5A4-46 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart 13 (DTC 61/C0261) Abnormal FL Speed Sensor Signal
Step Action Value(s) Yes No
1 Is there play in the FL wheel bearing? - Go to Step 10 Go to Step 2 2 Is there play in the FL speed sensor/sensor
rotor?
3 Is there powdered iron sticking to FL speed
sensor/sensor rotor?
4 Check the FL speed sensor. (Refer to Chart C-
1-1 or TC-1) Is the FL sensor output normal?
5 Is there a broken tooth or indentation in the
sensor rotor?
6 Using DVM, measure the resistance between
J-500 EHCU connector terminal 33 and ground.
Does the DVM display a resistance within the specified value?
7 1. Clear diagnostic trouble code.
2. Test drive and perform system self-check.
Does repeat trouble?
8 Is there damage or indentation in the speed
sensor?
9 1. Disconnect FL sensor connector.
2. Using DVM, measure the resistance between J-75 sensor connector terminal 2 and ground.
Does the DVM display a resistance within the specified value?
10 Adjust wheel bearing preload.
Is action complete?
11 Repair or replace speed sensor/sensor rotor.
Is action complete?
12 Repair speed sensor/sensor rotor.
Is action complete?
13 Replace sensor rotor.
Is action complete?
14 Replace FL speed sensor.
Is action complete?
15 Check the FL speed sensor circuit. Refer to
Chart 9. Is action complete?
16 Check for a poor connection and an open
circuit on the harness between EHCU and sensor connectors.
Refer to “Note on Intermittents” described in earlier this section.
Is action complete?
1000 k ohms or
1000 k ohms or
- Go to Step 11 Go to Step 3
- Go to Step 12 Go to Step 4
- Go to Step 5 Go to Step 8
- Go to Step 13 Go to Step 6
Go to Step 7 Go to Step 9
more
- Go to Step 18 Go to Step 16
- Go to Step 14 Go to Step 15
Go to Step 17 Go to Step 14
more
- Go to Step 19 -
- Go to Step 19 -
- Go to Step 19 -
- Go to Step 19 -
- Go to Step 19 -
- Verify repair
- Go to Step 19 -
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-47
Step Action Value(s) Yes No
17 1. Locate open circuit, poor connection or
short circuit on the harness between EHCU and sensor connectors.
2. Repair the harness.
Is action complete?
18 Replace EHCU.
Is action complete?
19 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
- Go to Step 19 Go to Step 19
- Go to Step 19 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 19
5A4-48 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart 14 (DTC 62/C0262) Abnormal FR Speed Sensor Signal
Step Action Value(s) Yes No
1 Is there play in the FR wheel bearing? - Go to Step 10 Go to Step 2 2 Is there play in the FR speed sensor/sensor
rotor?
3 Is there powdered iron sticking to FR speed
sensor/sensor rotor?
4 Check the FR speed sensor. (Refer to Chart
C-1-2 or TC-1) Is the FR sensor output normal?
5 Is there a broken tooth or indentation in the
sensor rotor?
6 Using DVM, measure the resistance between
J-500 EHCU connector terminal 11 and ground.
Does the DVM display a resistance within the specified value?
7 1. Clear diagnostic trouble code.
2. Test drive and perform system self-check.
Does repeat trouble?
8 Is there damage or indentation in the speed
sensor?
9 1. Disconnect FR sensor connector.
2. Using DVM, measure the resistance between J-74 sensor connector terminal 2 and ground.
Does the DVM display a resistance within the specified value?
10 Adjust wheel bearing preload.
Is action complete?
11 Repair or replace speed sensor/sensor rotor.
Is action complete?
12 Repair speed sensor/sensor rotor.
Is action complete?
13 Replace sensor rotor.
Is action complete?
14 Replace FR speed sensor.
Is action complete?
15 Check the FR speed sensor circuit. Refer to
Chart 10. Is action complete?
16 Check for a poor connection and an open
circuit on the harness between EHCU and sensor connectors.
Refer to “Note on Intermittents” described in earlier this section.
Is action complete?
1000 k ohms or
1000 k ohms or
- Go to Step 11 Go to Step 3
- Go to Step 12 Go to Step 4
- Go to Step 5 Go to Step 8
- Go to Step 13 Go to Step 6
Go to Step 7 Go to Step 9
more
- Go to Step 18 Go to Step 16
- Go to Step 14 Go to Step 15
Go to Step 17 Go to Step 14
more
- Go to Step 19 -
- Go to Step 19 -
- Go to Step 19 -
- Go to Step 19 -
- Go to Step 19 -
- Verify repair -
- Go to Step 19 -
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-49
Step Action Value(s) Yes No
17 1. Locate open circuit, poor connection or
short circuit on the harness between EHCU and sensor connectors.
2. Repair the harness.
Is action complete?
18 Replace EHCU.
Is action complete?
19 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
- Go to Step 19 Go to Step 19
- Go to Step 19 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 19
5A4-50 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart 15 (DTC 63/C0263) Abnormal RL Speed Sensor Signal
Step Action Value(s) Yes No
1 Is there play in the RL wheel bearing? - Go to Step 8 Go to Step 2 2 Is there play in the RL speed sensor/sensor
rotor?
3 Is there powdered iron sticking to RL speed
sensor/sensor rotor?
4 Check the RL speed sensor. (Refer to Chart C-
1-3 or TC-1) Is the RL sensor output normal?
5 Is there a broken tooth or indentation in the
sensor rotor?
6 1. Clear diagnostic trouble code.
2. Test drive and perform system self-check.
Does repeat trouble?
7 Is there damage or indentation in the speed
sensor?
8 Adjust wheel bearing preload.
Is action complete?
9 Repair or replace speed sensor/sensor rotor.
Is action complete?
10 Repair speed sensor/sensor rotor.
Is action complete?
11 Replace sensor rotor.
Is action complete?
12 Replace RL speed sensor.
Is action complete?
13 Check the RL speed sensor circuit. Refer to
Chart 11. Is action complete?
14 Check for a poor connection and an open
circuit on the harness between EHCU and sensor connectors.
Refer to “Note on Intermittents” described in earlier this section.
Is action complete?
15 Replace EHCU.
Is action complete?
16 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
- Go to Step 9 Go to Step 3
- Go to Step 10 Go to Step 4
- Go to Step 5 Go to Step 7
- Go to Step 11 Go to Step 6
- Go to Step 15 Go to Step 14
- Go to Step 12 Go to Step 13
- Go to Step 16 -
- Go to Step 16 -
- Go to Step 16 -
- Go to Step 16 -
- Go to Step 16 -
- Verify repair -
- Go to Step 16 -
- Go to Step 16 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 16
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-51
Chart 16 (DTC 64/C0264) Abnormal RR Speed Sensor Signal
Step Action Value(s) Yes No
1 Is there play in the RR wheel bearing? - Go to Step 8 Go to Step 2 2 Is there play in the RR speed sensor/sensor
rotor?
3 Is there powdered iron sticking to RR speed
sensor/sensor rotor?
4 Check the RR speed sensor. (Refer to Chart
C-1-4 or TC-1) Is the RR sensor output normal?
5 Is there a broken tooth or indentation in the
sensor rotor?
6 1. Clear diagnostic trouble code.
2. Test drive and perform system self-check.
Does repeat trouble?
7 Is there damage or indentation in the speed
sensor?
8 Adjust wheel bearing preload.
Is action complete?
9 Repair or replace speed sensor/sensor rotor.
Is action complete?
10 Repair speed sensor/sensor rotor.
Is action complete?
11 Replace sensor rotor.
Is action complete?
12 Replace RR speed sensor.
Is action complete?
13 Check the RR speed sensor circuit. Refer to
Chart 12. Is action complete?
14 Check for a poor connection and an open
circuit on the harness between EHCU and sensor connectors.
Refer to “Note on Intermittents” described in earlier this section.
Is action complete?
15 Replace EHCU.
Is action complete?
16 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
- Go to Step 9 Go to Step 3
- Go to Step 10 Go to Step 4
- Go to Step 5 Go to Step 7
- Go to Step 11 Go to Step 6
- Go to Step 15 Go to Step 14
- Go to Step 12 Go to Step 13
- Go to Step 16 -
- Go to Step 16 -
- Go to Step 16 -
- Go to Step 16 -
- Go to Step 16 -
- Verify repair -
- Go to Step 16 -
- Go to Step 16 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 16
5A4-52 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart 17 (DTC65/C0265) Tire Size Error
Step Action Value(s) Yes No
1 Does the tire size match the vehicle
specification?
2 Check wear and inflation of the tire.
Are they okay?
3 Are the sensor rotors normal? - Go to Step 4 Replace the
4 Test run the vehicle.
Does the malfunction repeat.
- Go to Step 2 Replace the
abnormal tire.
- Go to Step 3 Repair or
replace the
abnormal tire.
abnormal
sensor rotor.
-
Replace the
EHCU.
Recheck the
DTC.
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-53
Unit Inspection Procedure
This section describes the following inspection procedures referred to during “SYMPTOM
Speed Sensor Output Inspection Chart C-1-1 to C-1-4 Chart TC-1
DIAGNOSIS” and “DIAGNOSIS BY ‘ABS’ WARNING LIGHT ILLUMINATION PATTERN”:
without TECH 2 with TECH 2
Chart C-1-1 FL Speed Sensor Output Inspection Procedure
Step Action Value(s) Yes No
1 1. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, with all wheels off the ground.
4. Measure the AC voltage between J-500 EHCU connector terminals 32 and 33 while turning FL wheel at a speed of 0.5 RPS.
Does the DVM display a voltage within the specified value?
2 1. Disconnect FL sensor connector.
2. Using DVM, measure the resistance between J-75 sensor connector terminals 1 and 2.
Does the DVM display a resistance within the specified value?
3 1. Locate open circuit, poor connection or
short circuit on the harness between EHCU and sensor connectors.
2. Repair the harness.
Is action complete?
4 Replace FL sensor.
Is action complete?
5 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
200 mV or more Go to Step 5 Go to Step 2
1.0-2.0 k ohms Go to Step 4 Go to Step 3
- Go to Step 5 -
- Go to Step 5 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 5
5A4-54 ANTI-LOCK BRAKE SYSTEM (ABS)
Chart C-1-2 FR Speed Sensor Output Inspection Procedure
Step Action Value(s) Yes No
1 1. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, with all wheels off the ground.
4. Measure the AC voltage between J-500 EHCU connector terminals 10 and 11 while turning FR wheel at a speed of 0.5 RPS.
Does the DVM display a voltage within the specified value?
2 1. Disconnect FR sensor connector.
2. Using DVM, measure the resistance between J-74 sensor connector terminals 1 and 2.
Does the DVM display a resistance within the specified value?
3 1. Locate open circuit, poor connection or
short circuit on the harness between EHCU and sensor connectors.
2. Repair the harness.
Is action complete?
4 Replace FR sensor.
Is action complete?
5 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
200 mV or more Go to Step 5 Go to Step 2
1.0-2.0 k ohms Go to Step 4 Go to Step 3
- Go to Step 5 -
- Go to Step 5 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 5
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-55
Chart C-1-3 RL Speed Sensor Output Inspection Procedure
Step Action Value(s) Yes No
1 1. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, with all wheels off the ground.
4. Connect a 120 ohms resistor between J-500 EHCU connector terminal 22 and ground. Apply voltage of 12V to EHCU connector terminal 22.
5. Using DVM, measure the DC voltage between J-500 connector terminal 22 and ground while turning RL wheel at a speed of 0.5 RPS.
Does the DVM display a voltage within the specified value?
2 1. Turn the key off.
2. Disconnect RL sensor connector.
3. Connect a 120 ohms resistor between sensor connector terminal 2 (sensor side) and ground.
4. Apply 12V voltage at sensor connector terminal 1 (sensor side).
5. Using DVM, measure the DC voltage between sensor connector terminal 2 (sensor side) and ground while turning RL wheel at a speed of 0.5 RPS.
Does the DVM display a voltage within the specified value?
3 1. Locate open circuit, poor connection short
circuit on the harness between EHCU and sensor connectors.
2. Repair the harness.
Is action complete?
4 Replace RL sensor.
Is action complete?
5 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
0.2-4.5V Go to Step 5 Go to Step 2
0.2-4.5V Go to Step 3 Go to Step 4
- Go to Step 5 -
- Go to Step 5 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 5
5A4-56 ANTI-LOCK BRAKE SYSTEM (ABS)
Legend
(1) Battery (4) Speed Sensor (2) DVM (3) Resistor
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-57
Chart C-1-4 RR Speed Sensor Output Inspection Procedure
Step Action Value(s) Yes No
1 1. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, with all wheels off the ground.
4. Connect a 120 ohms resistor between J-500 EHCU connector terminal 21 and ground.
5. Using DVM, measure the DC voltage between J-500 connector terminal 21 and ground while turning RR wheel at a speed of 0.5 RPS.
Does the DVM display a voltage within the specified value?
2 1. Turn the key off.
2. Disconnect RR sensor connector.
3. Connect a 120 ohms resistor between sensor connector terminal 2 (sensor side) and ground.
4. Apply 12V voltage at sensor connector terminal 1 (sensor side).
5. Using DVM, measure the DC voltage between sensor connector terminal 2 (sensor side) and ground while turning RR wheel at a speed of 0.5 RPS.
Does the DVM display a voltage within the specified value?
3 1. Locate open circuit, poor connection short
circuit on the harness between EHCU and sensor connectors.
2. Repair the harness.
Is action complete?
4 Replace RR sensor.
Is action complete?
5 1. Reconnect all components, ensure all
components are properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
0.2-4.5V Go to Step 5 Go to Step 3
0.2-4.5V Go to Step 3 Go to Step 4
- Go to Step 5 -
- Go to Step 5 -
- Go to “Basic diagnostic flow
chart.”
Go to Step 5
5A4-58 ANTI-LOCK BRAKE SYSTEM (ABS)
Legend
(1) Battery (4) Speed Sensor (2) DVM (3) Resistor
Chart TC-1 Sensor Output Inspection Procedure (Use TECH 2)
Step Action Yes No
1 1. Connect TECH 2.
2. Check the minimum speed of each sensor by WHEEL SENSORS.
Is the sensor speed more than 5km/h (3mph)?
2 Check the sensor harness for suspected disconnection
(check while shaking harness/connector). Is the sensor harness connection normal?
3 Check the minimum speed of each sensor by WHEEL
SENSORS. Is the sensor speed more than 5 km/h (3mph)?
4 Check the sensor rotor.
Is the sensor rotor normal?
5 Check the minimum speed of each sensor by WHEEL
SENSORS. Is sensor speed more than 5 km/h (3 mph)?
6 Reconnect all components, ensure all components are
properly mounted. Was this step finished?
Go to Step 2 Go to Step 6
Replace speed
sensor. Go to Step 3 Go to Step 4 Go to Step 6
Go to Step 5 Replace sensor
Repair harness or
connector between
EHCU and speed
sensor. Go to Step 6
Repeat the “Basic
diagnostic flow
chart.”
Repair.
Go to Step 3
Go to Step 5 Go to Step 6
Go to Step 6
rotor.
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-59
Electronic Hydraulic Control Unit (EHCU)
Removal
1
3
Legend
(1) Brake Pipe (2) EHCU Bracket Fix Bolt & Nut (3) EHCU Bracket (4) Harness Connector (5) EHCU
5
Installation
To install, follow the removal steps in the reverse order, noting the following points.
NOTE:
If welding work is to be performed on the vehicle using an electric arc welder, the EHCU should be removed from the vehicle before the welding
4
2
operation begins.
Do not put a radio equipment etc, that emits strong radio wave near the EHCU.
Do not wet the control unit. If wetted, wipe off water immediately and dry it fully.
Never loosen any screw on the control unit.
Do not paint the control unit.
Prevent possible electrostatic discharge damage.
Do not touch the control unit pin type terminal with
a metalic tip of a screwdriver or tester.
Do not apply voltage to the terminal.
1. Disconnect battery ground cable.
2. Disconnect brake pipes.
3. Remove EHCU bracket fix bolts & nut.
4. Remove EHCU bracket.
5. Remove EHCU.
5A4-60 ANTI-LOCK BRAKE SYSTEM (ABS)
Front Speed Sensor
Front Speed Sensor and Associated Parts
Legend
(1) Speed Sensor Connector (2) Sensor Cable Fixing Bolt (3) Sensor Cable Fixing Bolt
Removal
1. Remove speed sensor connector.
2. Remove sensor cable fixing bolts.
3. Remove the speed sensor fixing bolt.
4. Remove speed sensor.
Inspection and Repair
1. Check the speed sensor pole piece for presence of foreign materials; remove any dirt, etc.
2. Check the pole piece for damage; replace speed sensor if necessary.
3. Check the speed sensor cable for short or open circuit, and replace with a new one if necessary. To check for cable short or open, bend or stretch the cable while checking for continuity.
(4) Sensor Fixing Bolt (5) Speed Sensor (6) Front
Installation
1. Install speed sensor and take care not to hit the speed sensor pole piece during installation.
2. Install speed sensor fixing bolt and tighten the fixing bolt to the specified torque.
Torque: 22 N⋅⋅⋅m (2.2kgf⋅⋅⋅⋅m/16lb⋅⋅⋅⋅ft)
3. Install speed sensor cable fixing bolts and tighten the fixing bolt to the specified torque.
Torque
Bolts (2): 22 N⋅⋅⋅m (2.2kgf⋅⋅⋅⋅m/16lb⋅⋅⋅⋅ft) Bolts (3): 45 N⋅⋅⋅m (4.6kgf⋅⋅⋅⋅m/33lb⋅⋅⋅⋅ft)
NOTE: Confirm that a white or yellow line marked on the cable is not twisted when connecting the speed sensor cable.
4. Connect speed sensor connector.
Front Speed Sensor Rotor
Front Speed Sensor Rotor and Associated Parts
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-61
Legend
(1) Disk Brake Assembly (2) Hub Cap (3) Cotter Pin (4) Hub Nut (5) Washer
Removal
1. Remove disc brake assembly and support the caliper assembly so that the brake hose is not stretched or damaged.
2. Remove hub cap.
3. Remove cotter pin and hub nut.
4. Remove washer.
5. Remove hub and disc assembly.
(6) Hub and Disc Assembly (7) Speed Sensor Rotor (8) Inner Bearing and Outer Bearing (9) Oil Seal
(10) Spacer
6. Remove speed sensor rotor.
7. Remove inner bearing, oil seal spacer.
5A4-62 ANTI-LOCK BRAKE SYSTEM (ABS)
Inspection and Repair
1. Check the speed sensor rotor for damage including tooth chipping, and if damaged, replace the speed sensor rotor.
Installation
1. Using a bench press, install speed sensor rotor.
2. Install spacer onto the knuckle spindle.
3. Apply grease into the outer and inner bearings and install bearings in the hub.
4. Install oil seal into hub and disc assembly and install hub and disc assembly on to the knuckle spindle.
Preload Adjustment
Adjust the wheel bearing as follows:
1. Tighten the nut until you are unable to manually rotate the hub and disc assembly.
2. Loosen the nut.
3. Attach a spring balancer to one stud. Gradually retighten the nut until the hub and disc assembly bearing is adjusted to the specified preload.
4. Install a cotter pin through the nut and knuckle and bend it over.
If the notch in the nut does not line up with the
cotter pin hole in the knuckle, tighten the nut until it does. Do not loosen the nut to line up a notch and the knuckle hole.
5. Apply grease into the hub cap and install it.
0.4N (40g/0.09lbf)
6. Install the disc brake assembly and tighten two bolts to the specified torque.
Torque: 221 N⋅⋅⋅⋅m (22.5kgf⋅⋅⋅⋅m/163lb⋅⋅⋅⋅ft)
Hub bearing preload
New Hub Bearing 9.8-24.5N (1-2.5kgf/2.2-5.5lbf) Reused Hub Bearing 4.9-19.6N (0.5-2kgf/1.1-
4.4lbf)
Rear Speed Sensor
Rear Speed Sensor and Associated Parts
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-63
Legend
(1) Brake Drum (2) Speed Sensor Fixing Bolt
(3) Speed Sensor (4) Speed Sensor Bracket
5A4-64 ANTI-LOCK BRAKE SYSTEM (ABS)
Removal
Legend
(1) Speed Sensor Connector (2) Front (3) Speed Sensor (4) Rear Axle
1. Disconnect speed sensor connector.
2. Remove brake drum.
3. Remove speed sensor fixing bolt.
4. Remove speed sensor.
5. Remove speed sensor bracket.
Inspection and Repair
1. Check the speed sensor for presence of foreign materials; remove any dirt, etc.
2. Check the speed sensor for damage, and replace the speed sensor if necessary.
3. Check the speed sensor harness for a short or an open, and replace with a new one if necessary. To check for harness short or open, bend or stretch the cable while checking for continuity.
Installation
1. Install speed sensor bracket and tighten the nut to the specified torque.
Torque: GVW Range 12,000 lbs. and 14,500 lbs. model 108 N⋅⋅⋅m (11kgf⋅⋅⋅⋅m/80lb⋅⋅⋅⋅ft) GVW Range 17,950 lbs. model 157 N⋅⋅⋅m (16kgf⋅⋅⋅⋅m/116lb⋅⋅⋅⋅ft)
2. Install the speed sensor and take care not to hit the speed sensor during installation.
3. Install the speed sensor fixing bolt and tighten it to the specified torque.
Torque: 18 N⋅⋅⋅m (1.8kgf⋅⋅⋅⋅m/13lb⋅⋅⋅⋅ft)
4. Install brake drum and tighten bolts to the specified torque.
Torque: 13 N⋅⋅⋅m (1.3kgf⋅⋅⋅⋅m/9.5lb⋅⋅⋅⋅ft)
5. Connect speed sensor connector.
NOTE: Confirm that the harness is not twisted when connecting the speed sensor connector.
Rear Speed Sensor Rotor
Rear Speed Sensor Rotor and Associated Parts
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-65
Legend
(1) Brake Drum (2) Axle Shaft (3) Outer Oil Seal (4) Lock Washer (5) Bearing Nut
Removal
1. Remove brake drum.
2. Remove axle shaft.
3. Remove outer oil seal, using a screwdriver.
4. Remove lock washer.
5. Remove bearing nut with a hub bearing nut wrench.
6. Remove hub assembly from axle case.
7. Remove outer bearing from hub assembly.
8. Remove speed sensor rotor from hub assembly.
9. Remove inner bearing and inner oil seal from axle case.
(6) Outer Bearing (7) Rear Hub (8) Speed Sensor Rotor (9) Inner Bearing
(10) Inner Oil Seal
Inspection and Repair
1. Check the speed sensor rotor for damage including tooth chipping. If damaged, replace speed sensor rotor.
Installation
1. Using a bench press, install speed sensor rotor.
NOTE: Do not reuse the sensor rotor.
2. Install spacer on to the axle case.
3. Apply grease into the outer and inner bearings and install bearings in the hub.
4. Install outer oil seal into hub.
5A4-66 ANTI-LOCK BRAKE SYSTEM (ABS)
5. Install hub assembly onto the axle case.
6. Set the lock nut with the notched line facing out.
Preload Adjustment
1) Turn the hub to the left and right several times to establish bearing conformity.
2) Use the bearing nut wrench to tighten the bearing nut until the hub can not be manually rotated.
3) Loosen the bearing nut until hub rotates easily.
6) Rotate the hub several times to the right and left.
7) Measure the bearing preload a second time.
8) Align the axle case groove with the closest bearing nut slit.
NOTE: If it is difficult to align the axle case and bearing nut, slightly tighten the bearing nut.
7. Install the lock washer with the lock washer tabs inserted to the axle case grooves. Install the lock bolts to prevent the bearing nut from loosening. Check that the lock washer tabs are inserted to the axle case grooves.
8. Apply grease to the outer oil seal lip inner and outer circumferences and install outer oil seal.
9. Clean the axle shaft. Apply gear oil to the axle shaft spline. Insert the axle shaft into the axle case. Take care not to damage the oil seal.
10. Tighten the axle shaft nuts to the specified torque a little at a time.
Torque: 46 N⋅⋅⋅m (4.7kgf⋅⋅⋅⋅m/34lb⋅⋅⋅⋅ft)
11. Install brake drum.
4) Set the spring balancer to the wheel pin in the position shown in the illustration.
5) Measure the hub bearing preload by carefully pulling on the spring balancer and noting the indicator reading.
Hub Bearing Preload (At Wheel Pin) 42-52 N (4.3-5.3kgf/9.4-11.6lbf)
Special Tools
ILLUSTRATION TOOL NO. TOOL NAME
5-8840-0385-0
(J-35616)
Connector test adapter kit
5-8840-0285-0
(J-39200)
High impedance multimeter
(1) PCMCIA Card (2) RS232 Loop Back
Connector (3) SAE 16/19 Adapter (4) DLC Cable (5) Tech 2
ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-67
LGBRK-WE-0101
You are requested to order this manual using the manual number that is shown above.
This manual is applicable for vehicles in all countries except the USA and Canada.
All rights reserved. This manual may not be reproduced in whole or in part, without the permis sion in writing of ISUZU MOTORS LIMITED.
Issued by
ISUZU MOTORS LIMITED
INTERNATIONAL SERVICE DEPARTMENT
Tokyo, Japan
First edition Jan., 2001
LGBRK-WE-0101 PRINTED IN JAPAN
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