INFINITI QX4 2005 Factory Service Manual

LAN-122
[CAN]
CAN SYSTEM (TYPE 3)
Revision: October 20052005 QX56
Front Air Control Circuit CheckUKS001A7
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 (L) and 35 (P).
OK or NG
OK >> Replace front air control.
NG >> Repair harness between front air control and data link
connector.
Transfer Control Unit Circuit CheckUKS001A8
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 (L) and 8 (P).
OK or NG
OK >> Replace transfer control unit.
NG >> Repair harness between transfer control unit and har-
ness connector E152. 34 (L) - 35 (P) : Approx. 54 - 66 Ω
PKIA8136E
7 (L) - 8 (P) : Approx. 54 - 66 Ω
PKIA6844E

CAN SYSTEM (TYPE 3)
LAN-123
[CAN]
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Revision: October 20052005 QX56
ABS Actuator and Electric Unit (Control Unit) Circuit CheckUKS001A9
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 (L) and 15 (P).
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 CheckUKS001AA
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 (L) and 40 (P).
OK or NG
OK >> Replace IPDM E/R.
NG >> Repair harness between IPDM E/R and harness con-
nector E152. 11 (L) - 15 (P) : Approx. 54 - 66 Ω
SKIA6872E
39 (L) - 40 (P) : Approx. 108 - 132 Ω
PKIA8141E

LAN-124
[CAN]
CAN SYSTEM (TYPE 3)
Revision: October 20052005 QX56
CAN Communication Circuit CheckUKS001AB
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
–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 (L) and 14
(P).
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 (L),
14 (P) and ground.
OK or NG
OK >> Check ECM and IPDM E/R. Refer to LAN-125, "ECM/
IPDM E/R INTERNAL CIRCUIT INSPECTION" .
NG >> Repair harness.
IPDM E/R Ignition Relay Circuit CheckUKS001AC
Check the following. If no malfunction is found, replace the IPDM E/R.

IPDM E/R power supply circuit. Refer to PG-26, "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" . 6 (L) - 14 (P) : Continuity should not exist.
PKIA2077E
6 (L) - Ground : Continuity should not exist.
14 (P) - Ground : Continuity should not exist.
PKIA2079E

CAN SYSTEM (TYPE 3)
LAN-125
[CAN]
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Revision: October 20052005 QX56
Component InspectionUKS001AD
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

LAN-126
[CAN]
CAN SYSTEM (TYPE 4)
Revision: October 20052005 QX56
CAN SYSTEM (TYPE 4)PFP:23710
System DescriptionUKS001NP
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Component Parts and Harness Connector LocationUKS001NQ
BKIA0121E

CAN SYSTEM (TYPE 4)
LAN-127
[CAN]
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Revision: October 20052005 QX56
SchematicUKS001NR
BKWA0067E

LAN-128
[CAN]
CAN SYSTEM (TYPE 4)
Revision: October 20052005 QX56
Wiring Diagram - CAN -UKS001NS
BKWA0404E

CAN SYSTEM (TYPE 4)
LAN-129
[CAN]
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Revision: October 20052005 QX56
BKWA0405E

LAN-130
[CAN]
CAN SYSTEM (TYPE 4)
Revision: October 20052005 QX56
BKWA0406E

CAN SYSTEM (TYPE 4)
LAN-131
[CAN]
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Revision: October 20052005 QX56
Work FlowUKS001NT
1. When there are no indications of “AUTO DRIVE POS.”, “BCM”, “HVAC”, “ALL MODE AWD/4WD” or
“IPDM E/R” on “SELECT SYSTEM” display of CONSULT-II, print the “SELECT SYSTEM”.
2. Print all the data of “SELF-DIAG RESULTS” for “ENGINE”, “A/T”, “ICC”, “AUTO DRIVE POS.”, “BCM”,
“HVAC”, “ALL MODE AWD/4WD”, “ABS” and “IPDM E/R” displayed on CONSULT-II.
3. Print all the data of “CAN DIAG SUPPORT MNTR” for “ENGINE”, “A/T”, “ICC”, “AUTO DRIVE POS.”,
“BCM”, “HVAC”, “ALL MODE AWD/4WD”, “ABS” and “IPDM E/R” displayed on CONSULT-II.
4. Attach the printed sheet of “SELECT SYSTEM”, “SELF-DIAG RESULTS” and “CAN DIAG SUPPORT
MNTR” onto the check sheet. Refer to LAN-133, "
CHECK SHEET" .
5. Based on the indications of “SELECT SYSTEM” and the results of “CAN DIAG SUPPORT MNTR”, puts a
check mark onto the items with “No indication”, “NG” or “UNKWN” in the check sheet table. Refer to LAN-
133, "CHECK SHEET" .
CAUTION:
“ALL MODE AWD/4WD” puts a check mark on the check
sheet when “Present” is “UNKWN” and “Past” is “0”.
PKIA2093E
PKIA8260E
PKIA8343E
SKIB3244E