ignition INFINITI QX56 2004 Factory Service Manual

CAN SYSTEM (TYPE 4)
LAN-161
[CAN]
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Revision: August 20072004 QX56
Driver Seat Control Unit Circuit CheckUKS001NZ
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check following terminals and connectors for damage, bend and loose connection (control unit side and
harness side).
–Driver seat control unit connector
–Harness connector P1
–Harness connector B37
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect driver seat control unit connector.
2. Check resistance between driver seat control unit harness con-
nector P2 terminals 3 (W) and 19 (R).
OK or NG
OK >> Replace driver seat control unit.
NG >> Repair harness between driver seat control unit and har-
ness connector B69.
Combination Meter Circuit CheckUKS001O0
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of combination meter for damage, bend and loose connection (meter side
and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect combination meter connector.
2. Check resistance between combination meter harness connec-
tor M24 terminals 11 (W) and 12 (R).
OK or NG
OK >> Replace combination meter.
NG >> Repair harness between combination meter and data
link connector. 3 (W) - 19 (R) : Approx. 54 - 66Ω
PKIA6842E
11 (W) - 12 (R) : Approx. 54 - 66Ω
PKIA6837E

LAN-162
[CAN]
CAN SYSTEM (TYPE 4)
Revision: August 20072004 QX56
Display Control Unit Circuit CheckUKS001O1
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of display control unit for damage, bend and loose connection (control unit
side and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect display control unit connector.
2. Check resistance between display control unit harness connec-
tor M95 terminals 25 (W) and 26 (R).
OK or NG
OK >> Replace display control unit.
NG >> Repair harness between display control unit and data
link connector.
BCM Circuit CheckUKS001O2
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of BCM for damage, bend and loose connection (control module side and
harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect BCM connector.
2. Check resistance between BCM harness connector M18 termi-
nals 39 (W) and 40 (R).
OK or NG
OK >> Replace BCM. Refer to BCS-19, "Removal and Installa-
tion of BCM" .
NG >> Repair harness between BCM and data link connector.25 (W) - 26 (R) : Approx. 54 - 66Ω
SKIA6884E
39 (W) - 40 (R) : Approx. 54 - 66Ω
SKIA6869E

CAN SYSTEM (TYPE 4)
LAN-163
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Revision: August 20072004 QX56
Data Link Connector Circuit CheckUKS001O3
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of data link connector for damage, bend and loose connection (connector
side and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
Check resistance between data link connector M22 terminals 6 (W)
and 14 (R).
OK or NG
OK >> Diagnose again. Refer to LAN-131, "Work Flow" .
NG >> Repair harness between data link connector and combi-
nation meter.
Steering Angle Sensor Circuit CheckUKS001O4
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of steering angle sensor for damage, bend and loose connection (sensor
side and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect steering angle sensor connector.
2. Check resistance between steering angle sensor harness con-
nector M47 terminals 3 (W) and 4 (R).
OK or NG
OK >> Replace steering angle sensor.
NG >> Repair harness between steering angle sensor and data
link connector. 6 (W) - 14 (R) : Approx. 54 - 66Ω
PKIA2077E
3 (W) - 4 (R) : Approx. 54 - 66Ω
PKIA6838E

LAN-164
[CAN]
CAN SYSTEM (TYPE 4)
Revision: August 20072004 QX56
Front Air Control Circuit CheckUKS001O5
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of front air control for damage, bend and loose connection (unit side and
harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect front air control connector.
2. Check resistance between front air control harness connector
M50 terminals 34 (W) and 35 (R).
OK or NG
OK >> Replace front air control.
NG >> Repair harness between front air control and data link
connector.
Transfer Control Unit Circuit CheckUKS001O6
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of transfer control unit for damage, bend and loose connection (control
unit side and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect transfer control unit connector.
2. Check resistance between transfer control unit harness connec-
tor E142 terminals 7 (W) and 8 (R).
OK or NG
OK >> Replace transfer control unit.
NG >> Repair harness between transfer control unit and har-
ness connector E152. 34 (W) - 35 (R) : Approx. 54 - 66Ω
PKIA8136E
7 (W) - 8 (R) : Approx. 54 - 66Ω
PKIA6844E

CAN SYSTEM (TYPE 4)
LAN-165
[CAN]
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Revision: August 20072004 QX56
ABS Actuator and Electric Unit (Control Unit) Circuit CheckUKS001O7
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of ABS actuator and electric unit (control unit) for damage, bend and loose
connection (control unit side and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect ABS actuator and electric unit (control unit) connector.
2. Check resistance between ABS actuator and electric unit (con-
trol unit) harness connector E125 terminals 11 (W) and 15 (R).
OK or NG
OK >> Replace ABS actuator and electric unit (control unit).
NG >> Repair harness between ABS actuator and electric unit
(control unit) and harness connector E152.
IPDM E/R Circuit CheckUKS001O8
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of IPDM E/R for damage, bend and loose connection (control module side
and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect IPDM E/R connector.
2. Check resistance between IPDM E/R harness connector E122
terminals 39 (W) and 40 (R).
OK or NG
OK >> Replace IPDM E/R.
NG >> Repair harness between IPDM E/R and harness con-
nector E152. 11 (W) - 15 (R) : Approx. 54 - 66Ω
SKIA6872E
39 (W) - 40 (R) : Approx. 108 - 132Ω
PKIA8141E

LAN-166
[CAN]
CAN SYSTEM (TYPE 4)
Revision: August 20072004 QX56
CAN Communication Circuit CheckUKS001O9
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Disconnect the following module and control unit connectors and check terminals for deformation, discon-
nection, looseness or damage.
–ECM
–A/T assembly
–ICC sensor
–ICC unit
–Driver seat control unit
–Combination meter
–Display control unit
–BCM
–Steering angle sensor
–Front air control
–Transfer control unit
–ABS actuator and electric unit (control unit)
–IPDM E/R
OK or NG
OK >> GO TO 2.
NG >> Repair or replace as necessary.
2. CHECK HARNESS FOR SHORT CIRCUIT
With all module and control unit connectors disconnected, check
continuity between data link connector M22 terminals 6 (W) and 14
(R).
OK or NG
OK >> GO TO 3.
NG >> Repair harness.
3. CHECK HARNESS FOR SHORT CIRCUIT
Check continuity between data link connector M22 terminals 6 (W),
14 (R) and ground.
OK or NG
OK >> Check ECM and IPDM E/R. Refer to LAN-167, "ECM/
IPDM E/R INTERNAL CIRCUIT INSPECTION" .
NG >> Repair harness.
IPDM E/R Ignition Relay Circuit CheckUKS001OA
Check the following. If no malfunction is found, replace the IPDM E/R.

IPDM E/R power supply circuit. Refer to PG-27, "IPDM E/R Power/Ground Circuit Inspection" . 6 (W) - 14 (R) : Continuity should not exist.
PKIA2077E
6 (W) - Ground : Continuity should not exist.
14 (R) - Ground : Continuity should not exist.
PKIA2079E

CAN SYSTEM (TYPE 4)
LAN-167
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Revision: August 20072004 QX56

Ignition power supply circuit. Refer to PG-13, "IGNITION POWER SUPPLY — IGNITION SW. IN ON
AND/OR START" .
Component InspectionUKS001OB
ECM/IPDM E/R INTERNAL CIRCUIT INSPECTION

Remove ECM and IPDM E/R from vehicle.

Check resistance between ECM terminals 94 and 86.

Check resistance between IPDM E/R terminals 39 and 40.
Unit TerminalResistance value (Ω)
(Approx.)
ECM 94 - 86
108 - 132
IPDM E/R 39 - 40
LKIA0037E

LT-3
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Revision: August 20072004 QX56 COMBINATION SWITCH READING FUNCTION . 109
EXTERIOR LAMP BATTERY SAVER CONTROL . 109
CAN Communication System Description ............ 109
Schematic ............................................................. 110
Wiring Diagram — TAIL/L — ................................ . 111
Terminals and Reference Values for BCM ............ 114
Terminals and Reference Values for IPDM E/R .... 115
How to Proceed With Trouble Diagnosis ............... 115
Preliminary Check ................................................. 116
CHECK POWER SUPPLY AND GROUND CIR-
CUIT ................................................................... 116
CONSULT-II Functions .......................................... 117
Parking, License Plate and/or Tail Lamps Do Not
Illuminate ............................................................... 117
Parking, License Plate and Tail Lamps Do Not Turn
OFF (After Approx. 10 Minutes) ........................... 120
Front Parking Lamp .............................................. 121
BULB REPLACEMENT ..................................... 121
Tail Lamp .............................................................. 121
BULB REPLACEMENT ..................................... 121
License Plate Lamp .............................................. 121
BULB REPLACEMENT ..................................... 121
REAR COMBINATION LAMP ................................ 122
Bulb Replacement (Turn Signal) .......................... 122
Removal and Installation ...................................... 122
.......................................................................... 122
TRAILER TOW ....................................................... 123
Component Parts and Harness Connector Location . 123
System Description .............................................. 123
TRAILER TAIL LAMP OPERATION .................. 124
TRAILER BRAKE, TURN SIGNAL AND HAZARD
LAMP OPERATION .......................................... 124
TRAILER BRAKE OPERATION ........................ 124
TRAILER POWER SUPPLY OPERATION ........ 124
Schematic ............................................................ 125
Wiring Diagram — T/TOW — ............................... 126
INTERIOR ROOM LAMP ........................................ 129
Component Parts and Harness Connector Location . 129
System Description .............................................. 130POWER SUPPLY AND GROUND ....................130
SWITCH OPERATION ......................................131
ROOM LAMP TIMER OPERATION ..................131
INTERIOR LAMP BATTERY SAVER CONTROL .132
Schematic .............................................................133
Wiring Diagram — INT/L — ..................................135
Terminals and Reference Values for BCM ............142
How to Proceed With Trouble Diagnosis ..............142
Preliminary Check ................................................143
INSPECTION FOR POWER SUPPLY AND
GROUND CIRCUIT ...........................................143
CONSULT-II Function (BCM) ...............................144
CONSULT-II OPERATION .................................144
WORK SUPPORT .............................................145
DATA MONITOR ...............................................145
ACTIVE TEST ...................................................146
Room/Map Lamp Control Does Not Operate .......146
Personal Lamp Control Does Not Operate (Room/
Map Lamps Operate) ............................................148
All Step/Foot/Puddle Lamps Do Not Operate .......149
All Interior Room Lamps Do Not Operate .............150
Ignition Keyhole Illumination Control Does Not
Operate .................................................................150
ILLUMINATION .......................................................152
Component Parts and Harness Connector Location .152
System Description ...............................................152
ILLUMINATION OPERATION BY LIGHTING
SWITCH ............................................................153
EXTERIOR LAMP BATTERY SAVER CONTROL .154
CAN Communication System Description ............154
Schematic .............................................................155
Wiring Diagram — ILL — ......................................158
Removal and Installation ......................................169
ILLUMINATION CONTROL SWITCH ................169
BULB SPECIFICATIONS ........................................170
Headlamp .............................................................170
Exterior Lamp .......................................................170
Interior Lamp/Illumination .....................................170

LT-6
HEADLAMP (FOR USA)
Revision: August 20072004 QX56
HEADLAMP (FOR USA)PFP:26010
Component Parts and Harness Connector LocationEKS0079P
System DescriptionEKS0079Q
Control of the headlamp system operation is dependent upon the position of the combination switch (lighting
switch). When the lighting switch is placed in the 2ND position, the BCM (body control module) receives input
requesting the headlamps (and tail lamps) illuminate. This input is communicated to the IPDM E/R (intelligent
power distribution module engine room) across the CAN communication lines. The CPU (central processing
unit) of the IPDM E/R controls the headlamp high and headlamp low relay coils. When energized, these relays
direct power to the respective headlamps, which then illuminate.
OUTLINE
Power is supplied at all times

to headlamp high relay, located in the IPDM E/R, and

to headlamp low relay, located in the IPDM E/R, and

to ignition relay, located in the IPDM E/R, and

through 20A fuse (No. 53, located in the IPDM E/R)

to CPU of the IPDM E/R, and

through 10A fuse [No. 19, located in the fuse block (J/B)]
WKIA3392E

HEADLAMP (FOR USA)
LT-7
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Revision: August 20072004 QX56

to combination meter terminal 8, and

through 50A fusible link (letter f , located in the fuse and fusible link box)

to BCM terminal 70.
With the ignition switch in the ON or START position, power is supplied

to ignition relay, located in the IPDM E/R, and

through 10A fuse [No. 14, located in the fuse block (J/B)]

to combination meter terminal 24, and

through 10A fuse (No. 59, located in the fuse and relay box)

to BCM terminal 38.
Ground is supplied

to BCM terminal 67 and

to combination meter terminal 17

through grounds M57, M61 and M79, and

to IPDM E/R terminals 38 and 59

through grounds E9, E15 and E24.
Low Beam Operation
With the lighting switch in 2ND position, the BCM receives input requesting the headlamps to illuminate. This
input is communicated to the IPDM E/R across the CAN communication lines. The CPU of the IPDM E/R con-
trols the headlamp low relay coil. When energized, this relay directs power

through 15A fuse (No. 41, located in the IPDM E/R)

through IPDM E/R terminal 54

to front combination lamp RH terminal 5, and

through 15A fuse (No. 40, located in the IPDM E/R)

through IPDM E/R terminal 52

to front combination lamp LH terminal 5.
Ground is supplied

to front combination lamp LH and RH terminal 1

through grounds E9, E15 and E24.
With power and ground supplied, low beam headlamps illuminate.
High Beam Operation/Flash-to-Pass Operation
With the lighting switch in 2ND position and placed in HIGH or PASS position, the BCM receives input request-
ing the headlamp high beams to illuminate. This input is communicated to the IPDM E/R across the CAN com-
munication lines. The CPU of the combination meter controls the ON/OFF status of the HIGH BEAM indicator.
The CPU of the IPDM E/R controls the headlamp high relay coil. When energized, this relay directs power

through 10A fuse (No. 34, located in the IPDM E/R)

through IPDM E/R terminal 56

to front combination lamp RH terminal 6, and

through 10A fuse (No. 35, located in the IPDM E/R)

through IPDM E/R terminal 55

to front combination lamp LH terminal 6.
Ground is supplied

to front combination lamp LH and RH terminal 2

through grounds E9, E15 and E24.
With power and ground supplied, the high beam headlamps illuminate.
XENON HEADLAMP
Xenon type headlamp is adopted to the low beam headlamps. Xenon bulbs do not use a filament. Instead,
they produce light when a high voltage current is passed between two tungsten electrodes through a mixture
of xenon (an inert gas) and certain other metal halides. In addition to added lighting power, electronic control
of the power supply gives the headlamps stable quality and tone color.
Following are some of the many advantages of the xenon type headlamp.