Infiniti QX56 (JA60). Manual - part 652

LAN

TROUBLE DIAGNOSIS

LAN-7

< FUNCTION DIAGNOSIS >

[CAN FUNDAMENTAL]

C

D

E

F

G

H

I

J

K

L

B

A

O

P

N

TROUBLE DIAGNOSIS

Condition of Error Detection

INFOID:0000000005152906

DTC of CAN communication is indicated on SELF-DIAG RESULTS on CONSULT-III if a CAN communication

signal is not transmitted or received between units for 2 seconds or more.

NOTE:

DTCs of CAN communication are follows:

• U0101

• U0140

• U0164

• U1000

• U1001

CAN COMMUNICATION SYSTEM ERROR

• CAN communication line open (CAN-H, CAN-L, or both)

• CAN communication line short (ground, between CAN communication lines, other harnesses)

• Error of CAN communication control circuit of the unit connected to CAN communication line

WHEN DTC OF CAN COMMUNICATION IS INDICATED EVEN THOUGH CAN COMMUNICATION
SYSTEM IS NORMAL

• Removal/installation of parts: Error may be detected when removing and installing CAN communication unit

and related parts while turning the ignition switch ON. (A DTC except for CAN communication may be

detected.)

• Fuse blown out (removed): CAN communication of the unit may cease.

• Voltage drop: Error may be detected if voltage drops due to discharged battery when turning the ignition

switch ON (Depending on the control unit which carries out CAN communication).

• Error may be detected if the power supply circuit of the control unit, which carries out CAN communication,

malfunctions (Depending on the control unit which carries out CAN communication).

• Error may be detected if reprogramming is not completed normally.

CAUTION:

CAN communication system is normal if DTC of CAN communication is indicated on SELF-DIAG

RESULTS of CONSULT-III under the above conditions. Erase the memory of the self-diagnosis of each

unit.

Symptom When Error Occurs in CAN Communication System

INFOID:0000000005146445

In CAN communication system, multiple units mutually transmit and receive signals. Each unit cannot transmit

and receive signals if any error occurs on CAN communication line. Under this condition, multiple control units

related to the root cause malfunction or go into fail-safe mode.

ERROR EXAMPLE

NOTE:

• Each vehicle differs in symptom of each unit under fail-safe mode and CAN communication line wiring.

• Refer to 

LAN-36, "Abbreviation List"

 for the unit abbreviation.

LAN-8

< FUNCTION DIAGNOSIS >

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSIS

Example: TCM branch line open circuit

Example: Data link connector branch line open circuit

SKIB8738E

Unit name

Symptom

ECM

Engine torque limiting is affected, and shift harshness increases.

BCM

Reverse warning chime does not sound.

EPS control unit

Normal operation.

Combination meter

• Shift position indicator and OD OFF indicator turn OFF.
• Warning lamps turn ON.

ABS actuator and electric unit (control unit)

Normal operation.

TCM

No impact on operation.

IPDM E/R

Normal operation.

SKIB8739E

LAN

TROUBLE DIAGNOSIS

LAN-9

< FUNCTION DIAGNOSIS >

[CAN FUNDAMENTAL]

C

D

E

F

G

H

I

J

K

L

B

A

O

P

N

NOTE:

• When data link connector branch line is open, transmission and reception of CAN communication signals

are not affected. Therefore, no symptoms occur. However, be sure to repair malfunctioning circuit.

• When data link connector branch line is open, “ECU list” displayed on the CONSULT-III “CAN DIAG SUP-

PORT MNTR” may be the same as when the CAN communication line has short-circuit. However, symp-

toms differ depending on the case. See below chart for the differences.

Example: Main Line Between Data Link Connector and ABS Actuator and Electric Unit (Control Unit) Open Circuit

Unit name

Symptom

ECM

Normal operation.

BCM

EPS control unit

Combination meter

ABS actuator and electric unit (control unit)

TCM

IPDM E/R

“ECU list” on the “CAN DIAG 

SUPPORT MNTR”

(CONSULT-III)

Difference of symptom

Data link connector branch line open circuit

All Diag on CAN units are not 
indicated.

Normal operation.

CAN-H, CAN-L harness short-circuit

Most of the units which are connected to the CAN 
communication system enter fail-safe mode or are 
deactivated.

SKIB8740E

Unit name

Symptom

ECM

Engine torque limiting is affected, and shift harshness increases.

BCM

• Reverse warning chime does not sound.
• The front wiper moves under continuous operation mode even though the front wip-

er switch being in the intermittent position.

EPS control unit

The steering effort increases.

Combination meter

• The shift position indicator and OD OFF indicator turn OFF.
• The speedometer is inoperative.
• The odo/trip meter stops.

ABS actuator and electric unit (control unit)

Normal operation.

LAN-10

< FUNCTION DIAGNOSIS >

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSIS

Example: CAN-H, CAN-L Harness Short Circuit

TCM

No impact on operation.

IPDM E/R

When the ignition switch is ON,
• The headlamps (Lo) turn ON.
• The cooling fan continues to rotate.

Unit name

Symptom

SKIB8741E

Unit name

Symptom

ECM

• Engine torque limiting is affected, and shift harshness increases.
• Engine speed drops.

BCM

• Reverse warning chime does not sound.
• The front wiper moves under continuous operation mode even though the front 

wiper switch being in the intermittent position.

• The room lamp does not turn ON.
• The engine does not start (if an error or malfunction occurs while turning the igni-

tion switch OFF.)

• The steering lock does not release (if an error or malfunction occurs while turning 

the ignition switch OFF.)

EPS control unit

The steering effort increases.

Combination meter

• The tachometer and the speedometer do not move.
• Warning lamps turn ON.
• Indicator lamps do not turn ON.

ABS actuator and electric unit (control unit)

Normal operation.

TCM

No impact on operation.

IPDM E/R

When the ignition switch is ON,
• The headlamps (Lo) turn ON.
• The cooling fan continues to rotate.