The most important purpose of diagnostics is to
quickly determine which part is malfunctioning, to
save time and labor.
2. IDENTIFICATION OF TROUBLE SYMPTOM
Determine what the problem is based on the symptom.
3. PROBABLE CAUSE OF TROUBLE
Look at the wiring diagram and check the system’s
circuit. Then check the switch, relay, fuse, ground,
etc.
4. LOCATION AND REPAIR OF TROUBLE
1) Using the diagnostics, narrow down the causes.
2) If necessary, use a voltmeter, ohmmeter, etc.
3) Before replacing certain component parts
(switch, relay, etc.), check the power supply,
ground, for open wiring harness, poor connectors,
etc. If no problem is encountered, check the component parts.
5) The circuit is in good order. If a problem such as
a light failing to illuminate occurs, use the procedures outlined above to track down the malfunction.
2. CIRCUIT CONTINUITY CHECKS
1) Disconnect the battery terminal or connector so
there is no voltage between the check points.
Contact the two leads of an ohmmeter to each of
the check points.
If the circuit has diodes, reverse the two leads and
check again.
2) Use an ohmmeter to check for diode continuity.
When contacting the negative lead to the diode
positive side and the positive lead to the negative
side, there should be continuity.
When contacting the two leads in reverse, there
should be no continuity.
5. SYSTEM OPERATION CHECK
After repairing, ensure that the system operates
properly.
B: BASIC INSPECTION
1. VOLTAGE MEASUREMENT
1) Using a voltmeter, connect the negative lead to a
good ground point or negative battery terminal and
the positive lead to the connector or component terminal.
2) Contact the positive lead of the voltmeter on
connector (A). The voltmeter will indicate a voltage.
3) Shift the positive lead to connector (B). The voltmeter will indicate no voltage.
To power
supply
Fuse
(A)
V
Switch
Light
(B)
Continuity No continuity
WI-02740
3) The symbol “ — ” indicates that continuity
exists between two points or terminals. For example, when a switch position is at “3”, continuity exists among terminals 1, 3 and 6, as shown in the
table below.
Te rm ina l
Switch Position
OFF
1
2
3
4
1
234
56
WI-02741
WI-02739
4) With the test set-up held as it is, turn the switch
to ON. The voltmeter will indicate a voltage and, at
the same time, the light will illuminate.
WI-3
08TR_VDC_US.book 4 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
WIRING SYSTEM
3. HOW TO DETERMINE AN OPEN CIRCUIT
1) WITH VOLTMETER:
An open circuit is determined by measuring the
voltage between respective connectors and ground
using a voltmeter, starting with the connector closest to the power supply. The power supply must be
turned ON so that current flows in the circuit. If voltage is not present between a particular connector
and ground, the circuit between that connector and
the previous connector is open.
Open circuit or wiring
V
12V
2) WITH OHMMETER:
Disconnect all connectors affected, and check continuity in the wiring between adjacent connectors.
When the ohmmeter indicates “infinite”, the wiring
is open.
V
0V
WI-02742
Open circuit
4. HOW TO DETERMINE A SHORT CIRCUIT
1) WITH TEST LIGHT:
Connect a test light (rated at approx. 3 watts) in
place of the blown fuse and allow current to flow
through the circuit. Disconnect one connector at a
time from the circuit. Starting with the one located
farthest from the power supply. If the test light goes
out when a connector is disconnected, the wiring
between that connector and the next connector
(farther from the power supply) is shorted.
Test light
Shorted wiring
Fuse holder
WI-02744
2) WITH OHMMETER:
Disconnect all affected connectors, and check continuity between each connector and ground. When
the ohmmeter indicates continuity between a particular connector and a ground, that connector is
shorted.
Shorted connector
WI-09860
WI-02745
WI-4
08TR_VDC_US.book 5 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
C: HOW TO READ WIRING DIAGRAMS
1. WIRING DIAGRAM
The wiring diagram of each system is illustrated so
that you can understand the path through which the
electric current flows from the battery.
Sketches and codes are used in the diagrams.
They should read as follows:
•Each connector and its terminal position are indicated by a sketch of the connector in a disconnected state which is viewed from the front.
2
1
3
4
WIRING SYSTEM
4
Viewed from this direction
WI-02746
•The number of poles or pins, presence of a lock are indicated in the sketch of each connector. In the
sketch, the highest pole number refers to the number of poles which the connector has. For example, the
sketch of the connector shown in figure indicates the connector has 9 poles.
Connector used in vehicle
SketchSymbolNumber of poles
Double frames
43
98
Indicates the number of poles.
Indicates a lock is included.
12
56
Indicates a lock
is included.
2
65
7
3
8
7
Connector shown in wiring diagram
1
4
9
Numbered in order from upper
right to lower left.
Numbered in order from upper
left to lower right
Single frame
WI-02747
WI-5
08TR_VDC_US.book 6 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
WIRING SYSTEM
•When one set of connectors is viewed from the
front side, the pole numbers of one connector are
symmetrical to those of the other. When these two
connectors are connected as a unit, the poles
which have the same number are joined.
1
2
3
6
5
44
3
6
1
2
5
WI-00107
•WIRING DIAGRAM:
The connectors are numbered along with the number of poles, external colors, and mating connections in the accompanying list.
•The sketch of each connector in the wiring diagram usually shows the (A) side of the connector.
The relationship between the wire color, terminal
number and connector is described in the figure.
•The following color codes are used to indicate
the colors of the wires.
Color codeColor
LBlue
BBlack
YYellow
GGreen
RRed
WWhite
BrBrown
LgLight green
GrGray
PPink
OrOrange
SbLight blue
VViolet
SASealed (Inner)
SBSealed (Outer)
YG
NOTE:
A wire which runs in one direction from a connector
terminal sometimes may have a different color from
that which runs in the other direction from that terminal.
i2
BR
1
RW
3
Wire color :
(No. 1 terminal)
BR
RW (No. 3 terminal)
(A)
i2F4
12
34
WI-02748
•In the wiring diagram, connectors which have no
terminal number refer to one-pole types. Sketches
of these connectors are omitted intentionally.
BB
SA
SB10
YL9
YG8
SB22
SA20
SB
YL
SB
YL2
YG1
SA1
WI-00110
B15F10
WI-00109
WI-6
08TR_VDC_US.book 7 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
WIRING SYSTEM
•The wire color code, which consists of two letters
(or three letters including Br or Lg), indicates the
standard color (base color of the wire covering) by
its first letter and the stripe marking by its second
letter.
YB
BlackMarking color :
Reference color :Yellow
WI-03797
•The table lists the nominal sectional areas and
allowable currents of the wires.
CAUTION:
When replacing or repairing a wire, be sure to
use the same size and type of the wire which
was originally used.
NOTE:
•The allowable current in the table indicates the
tolerable amperage of each wire at an ambient
temperature of 40°C (104°F).
•The allowable current changes with ambient
temperature. Also, it changes if a bundle of more
than two wires is used.
•Each unit is either directly grounded to the body
or indirectly grounds through a harness ground terminal. Different symbols are used in the wiring diagram to identify the two grounding systems.
B
Direct groundIndirect terminal
ground
WI-02750
•The ground points shown in the wiring diagram
refer to the following:
NOTE:
All wiring harnesses are provided with a ground
point which should be securely connected.
: AIRBAG GROUND
GAB
: BODY GROUND
GB
: REAR DEFOGGER
GD
GROUND
: ENGINE GROUND
GE
: RADIO GROUND
GR
: VDC GROUND
GV
WI-19724
WI-7
08TR_VDC_US.book 8 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
WIRING SYSTEM
•Relays are classified as normally-open or normally-closed.
The normally-closed relay has one or more contacts. The wiring diagram shows the relay mode when the energizing circuit is OFF.
Relay type
Normally-open type
Normally-closed type
4-pole
6-pole
4-pole
Energizing circuit OFF
Energizing circuit ON
Mixed type
Key to symbols:
: Current flows.
: Current does not flow.
6-pole
WI-16724
WI-8
08TR_VDC_US.book 9 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
•Each connector number shown in the wiring diagram corresponds to that in the wiring harness. The
location of each connector in the actual vehicle is
determined by reading the first character of the
connector (for example, a “F” for F8, “i” for i16, etc.)
and the type of wiring harness. The first character
of each connector number corresponds to the area
or system of the vehicle.
Each connector number
shown in wiring diagram
corresponds to that in
BG2
B1
F19
BG3
B2
F22
the vehicle.
(GRAY)
F3
(GRAY)
F19
1 2
WI-02753
WI-9
08TR_VDC_US.book 10 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
WIRING SYSTEM
D: SYMBOLS IN WIRING DIAGRAMS
A number of symbols are used in each wiring diagram to easily identify parts or circuits.
Example
RELAY
SYMBOLS OF
WIRE
CONNECTION
AND CROSSING
SPECIFICATION
CLASSIFICATION
: WITHOUT REAR D EFOGGER
OR
: WITH RE AR DEFO GGER
WR
DIODE
SBF-1 100A
HEADLIGHT
RELAY
RH
No.3 10A
3
F39
LR
H/L(2L)-01
HEADLIGHT LH
LOW
HEADLIGHT RH
LOW
DIMMER &
PASS IN G SWI TC H
UP
LOW PA SS
LIGHTING SWITCH
1
2
OFF
GROUND
HF
HU
HL
HC
TC
EL
DIODE
E
No.9 15A
7
LW
MB-11
HIGH
HIGH
MAIN FUSE B OX (M/ B)
HEADLIGHT
RELAY
LH
No.8 15A
2
RL
MB-10
RL2
R1
YL3
F23
LW2
R1
YL3
F7
WROR
3
LY8
RY7
2
17
YB
16
B1716
LY
13 13
B71
YB1
RY2
B112
REF TO. GND-02
5
G
MB-10
M/B FUSE NO. 8
B
P-SUP-02
A
P-SUP-02
B
P-SUP-02
C
P-SUP-04
D
POWER SUPPLY
ROUTING
TO POWE R SUP PLY CIRC UIT
FB-16
MB-11
F/B FUSE NO. 11
M/B FUSE NO. 9
RL
LW
LW 4
LW
R3
R
YL
2
YL
F44
REF TO. FOG(H4)-01
REF TO. FOG(H6)-01
P
R4
PARK IN G
BRAKE
SWITCH
B61
SDSD
WG
REF TO. ST(MT)-01
REF TO. ST(AT)-01
WIRE TRACING
ON EXTENDED
WIRING DIAGRAMS
MB-5
HEADLIGHT
RELAY
(IG)
LB
GR
F45
B62
LB H1
LW B1
RA1
B36
SMJ
SMJ
SMJ
SPECIFICATION
CLASSIFICATION
PP17
R3
B99
WG
PP7
R1
B97
FUSE No. & RATING
SBF-6 30A
SBF-4 50A
SBF-3 50A
No.2 15A
SBF-2 50A
No.1 20A
CONNECTOR-1
2
R
LR
L
FUSE &
RELAY
BOX (F /B)
F36F38F68
R 3
W
BW 2
A:
B51
B:
i5
C:
B52
D:
B152
E:
B158
F:
F40
G:
F41
P-SUP-04
M
P-SUP-04
L
P-SUP-04
K
TWISTED PAIR LINE
P-SUP-04
J
P-SUP-03
I
P-SUP-03
H
P-SUP-04
G
P-SUP-03
F
P-SUP-04
E
Or
BG
LgB
D4
D7
D11
No.5 10A
A2
A3
BL G1
BR D10
BG G7
WR G4
1
3
CONNECTOR-2
FB-37
FB-35
FB-34
FB-36
G:
(GRAY)
F41
(BLACK)
(BLACK)
A:
1 2 3
4 5 6 7 8
F44
1234
5 6 7 8
B51
C:
B52
1 2 3
: SEDAN
SD
: WAGON
WG
4 5 6 7
B112
F7
F23
1 2
123
CONNECTOR SKETCH
WI-16198
WI-10
08TR_VDC_US.book 11 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
WIRING SYSTEM
1. RELAY
A symbol used to indicate a relay.
2. CONNECTOR 1
The sketch of the connector indicates the one-pole
types.
3. WIRING CONNECTION
Some wiring diagrams are indicated in foldouts for
convenience. Wiring destinations are indicated
where necessary by corresponding symbols.
(When two pages are needed for clear indication)
4. FUSE NO. & RATING
The “FUSE No. & RATING” corresponds with that
used in the fuse box (main fuse box, fuse and joint
box).
5. CONNECTOR 2
•Each connector is indicated by a symbol.
•Each terminal number is indicated in the corresponding wiring diagram in an abbreviated form.
•For example, terminal number “G4” refers to No.
4 terminal of connector (G: F41) shown in the connector sketch.
10.SYMBOLS OF WIRE CONNECTION AND
CROSSING
Symbol
Symbol Refers to wires which are
Refers to wires which are
connected and branched
at the dot point.
crossed but not connected.
WI-02755
11.POWER SUPPLY CIRCUIT
A symbol is used to indicate the power supply in
each wiring diagram.
“MB-5”, “MB-6”, etc., which are used as power supply symbols throughout the text, correspond with
those shown in the “DC POWER SUPPLY CIRCUIT” in the wiring diagram.
Accordingly, using the “DC POWER SUPPLY CIRCUIT” and wiring diagrams permits service personnel to understand the entire electrical arrangement
of a system.
6. CONNECTOR SKETCH
•Each connector sketch clearly identifies the
shape and color of a connector as well as terminal
locations. Non-colored connectors are indicated in
white or natural color.
•When more than two types of connector number
are indicated in a connector sketch, it means that
the same type connectors are used.
7. GROUND
Each grounding point can be located easily by referring to the corresponding wiring harness.
8. DIODE
A symbol is used to indicate a diode.
9. WIRE TRACING ON EXTENDED WIRING
DIAGRAMS
For a wiring diagram extending over at least two
pages, a symbol (consisting of the same characters
with arrows), facilitates wire tracing from one page
to the next.
A ←→ A, B ←→ B
12.CLASSIFICATION BY SPECIFICATION
When the wiring diagram differ according to vehicle
specifications, the specification difference is described by using abbreviations.
13.TWISTED PAIR LINE
The twisted pair line is indicated by a symbol in the
wiring diagrams.
TWISTED PAIR LINE
B26
10
P
9
V
P
V B25
WI-16199
WI-11
08TR_VDC_US.book 12 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
WIRING SYSTEM
E: CONNECTOR SYMBOL IN WIRING HARNESS
A number of connector symbols are used in each wiring diagram to easily identify the wiring harness connectors.
Standard type: Female
Pole: From 1 to 8Pole: From 9 to 20Pole: More than 21
Standard type: Male
Water proof type: Female
Pole: From 1 to 8Pole: From 9 to 20Pole: More than 21
Water proof type: Male
WI-02756
WI-12
08TR_VDC_US.book 13 ページ 2012年2月10日 金曜日 午後1時43分
Basic Diagnostic Procedure
F: ABBREVIATION IN WIRING
DIAGRAMS
Abbr.Full name
A/CAir Conditioner
A/FAir/Fuel (Air fuel ratio sensor)
ABSAnti-lock Brake System
ACCAccessory
ALTGenerator
ASSYAssembly
ATE l ec t r on i c al l y c o n trolled fully-automatic
AUXAuxiliary Audio Input Terminal
AWDAll Wheel Drive
B, BATBattery
CANController Area Network
CPUCentral Processing Unit
ECMEngine Control Module
EEPROM
EGRExhaust Gas Recirculation
F/BFuse & Relay box
FWDFront Wheel Drive
GPSGlobal Positioning System
H/LHeadlight
HIHigh
HIDHigh Intensity Discharge
I/FInterface
IGIgnition
L, LHLeft Hand
LCDLiquid Crystal Display
LOLow
M/BMain Fuse Box
MFDMulti Function Display
OPOptional Parts or Open
R, RHRight Hand
SBFSlow Blow Fuse
STStarter
TCSTraction Control System
TCMAT Control Module
TPMTire Pressure Monitor
U, UPUp
VDCVehicle Dynamics Control
Electronically Erasable and Programmable Read Only Memory
WIRING SYSTEM
WI-13
08TR_VDC_US.book 14 ページ 2012年2月10日 金曜日 午後1時43分
Working Precautions
WIRING SYSTEM
2. Working Precautions
A: PRECAUTIONS WHEN WORKING
WITH THE PARTS MOUNTED ON
THE VEHICLE
1) When working under a vehicle which is jackedup, always be sure to use rigid rack.
2) The parking brake must always be applied during working. Also, in automatic transmission vehicles, keep the select lever set to the P (Parking)
range.
3) Be sure the workshop is properly ventilated
when running the engine. Further, be careful not to
touch the belt or fan while the engine is operating.
4) Be careful not to touch hot metal parts, especially the radiator and exhaust system immediately after the engine has been turned off.
B: PRECAUTIONS IN TROUBLE
DIAGNOSIS AND REPAIR OF
ELECTRIC PARTS
1) The battery cable must be disconnected from
the battery’s (–) terminal, and the ignition switch
must be set to the OFF position, unless otherwise
required by the diagnostics.
2) Securely fasten the wiring harness with clamps
and clips so that the harness does not interfere with
the body end parts or edges and bolts or screws.
3) When installing parts, be careful not to catch
them on the wiring harness.
4) When disconnecting a connector, do not pull the
wires, but pull while holding the connector body.
5) Some connectors are provided with a lock. One
type of such a connector is disconnected by pushing the lock, and the other, by moving the lock up.
In either type the lock shape must be identified before attempting to disconnect the connector.
To connect, insert the connector until it snaps and
confirm that it is connected securely.
EXAMPLE
WI-02758
6) When checking continuity between connector
terminals, or measuring voltage across the terminal
and ground, always contact tester probe(s) on terminals from the wiring connection side. If the probe
is too thick to gain access to the terminal, use “mini”
test leads.
To check water-proof connectors (which are not
measurable from the wiring side), contact test
probes on the terminal side. Be careful not to bend
or damage the terminals.
WI-02757
WI-09366
7) Sensors, relays, electrical unit, etc., are sensitive to strong impacts.
Handle them with care so that they are not dropped
or mishandled.