2004 INFINITI QX56 Air

CAN SYSTEM (TYPE 2)
LAN-85
[CAN]
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LAN
Revision: August 20072004 QX56
Display Control Unit Circuit CheckUKS001NF
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 CheckUKS001NG
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

LAN-86
[CAN]
CAN SYSTEM (TYPE 2)
Revision: August 20072004 QX56
Data Link Connector Circuit CheckUKS001NH
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-55, "Work Flow" .
NG >> Repair harness between data link connector and combi-
nation meter.
Steering Angle Sensor Circuit CheckUKS001NI
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

CAN SYSTEM (TYPE 2)
LAN-87
[CAN]
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LAN
Revision: August 20072004 QX56
Front Air Control Circuit CheckUKS001NJ
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.
ABS Actuator and Electric Unit (Control Unit) Circuit CheckUKS001NK
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. 34 (W) - 35 (R) : Approx. 54 - 66Ω
PKIA8136E
11 (W) - 15 (R) : Approx. 54 - 66Ω
SKIA6872E

LAN-88
[CAN]
CAN SYSTEM (TYPE 2)
Revision: August 20072004 QX56
IPDM E/R Circuit CheckUKS001NL
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.
CAN Communication Circuit CheckUKS001NM
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
–ABS actuator and electric unit (control unit)
–IPDM E/R
OK or NG
OK >> GO TO 2.
NG >> Repair or replace as necessary.39 (W) - 40 (R) : Approx. 108 - 132Ω
PKIA8141E

CAN SYSTEM (TYPE 2)
LAN-89
[CAN]
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LAN
Revision: August 20072004 QX56
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-89, "ECM/
IPDM E/R INTERNAL CIRCUIT INSPECTION" .
NG >> Repair harness.
IPDM E/R Ignition Relay Circuit CheckUKS001NN
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" .

Ignition power supply circuit. Refer to PG-13, "IGNITION POWER SUPPLY — IGNITION SW. IN ON
AND/OR START" .
Component InspectionUKS001NO
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 40.6 (W) - 14 (R) : Continuity should not exist.
PKIA2077E
6 (W) - Ground : Continuity should not exist.
14 (R) - Ground : Continuity should not exist.
PKIA2079E
Unit TerminalResistance value (Ω)
(Approx.)
ECM 94 - 86
108 - 132
IPDM E/R 39 - 40
LKIA0037E

LAN-110
[CAN]
CAN SYSTEM (TYPE 3)
Revision: August 20072004 QX56
Case 12
Check front air control circuit. Refer to LAN-122, "Front Air Control Circuit Check" .
PKIA8080E
PKIA8167E

CAN SYSTEM (TYPE 3)
LAN-115
[CAN]
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LAN
Revision: August 20072004 QX56
Case 18
Check IPDM E/R ignition relay circuit continuously sticks “ON”. Refer to LAN-124, "IPDM E/R Ignition Relay
Circuit Check" .
Circuit Check Between TCM and Driver Seat Control UnitUKS0019W
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 (connector side and
harness side).
–Harness connector F33
–Harness connector E19
–Harness connector E34
–Harness connector B40
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect A/T assembly connector and harness connector F33.
2. Check continuity between A/T assembly harness connector F9
terminals 3 (W), 8 (R) and harness connector F33 terminals 12
(W), 11 (R).
OK or NG
OK >> GO TO 3.
NG >> Repair harness.
PKIA8086E
3 (W) - 12 (W) : Continuity should exist.
8 (R) - 11 (R) : Continuity should exist.
PKIA6831E

LAN-116
[CAN]
CAN SYSTEM (TYPE 3)
Revision: August 20072004 QX56
3. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect harness connector E34.
2. Check continuity between harness connector E19 terminals 12
(W), 11 (R) and harness connector E34 terminals 24 (W), 23 (R).
OK or NG
OK >> GO TO 4.
NG >> Repair harness.
4. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect driver seat control unit connector.
2. Check continuity between harness connector B40 terminals 24
(W), 23 (R) and driver seat control unit harness connector P2
terminals 3 (W), 19 (R).
OK or NG
OK >> Connect all the connectors and diagnose again. Refer to
LAN-95, "
Work Flow" .
NG >> Repair harness.
Circuit Check Between Driver Seat Control Unit and Data Link ConnectorUKS0019X
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 (connector side and
harness side).
–Harness connector B69
–Harness connector M40
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 and harness connector B69.
2. Check continuity between driver seat control unit harness con-
nector P2 terminals 3 (W), 19 (R) and harness connector B69
terminals 51J (W), 52J (R).
OK or NG
OK >> GO TO 3.
NG >> Repair harness.12 (W) - 24 (W) : Continuity should exist.
11 (R) - 23 (R) : Continuity should exist.
PKIA6832E
24 (W) - 3 (W) : Continuity should exist.
23 (R) - 19 (R) : Continuity should exist.
PKIA6840E
3 (W) - 51J (W) : Continuity should exist.
19 (R) - 52J (R) : Continuity should exist.
PKIA6841E