Nissan Quest E52. Manual - part 824

LAN-10

< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSIS

TROUBLE DIAGNOSIS

Component Description

INFOID:0000000009653521

Condition of Error Detection

INFOID:0000000009653522

DTC (e.g. U1000 and U1001) of CAN communication is indicated on SELF-DIAG RESULTS on CONSULT if a
CAN communication signal is not transmitted or received between units for 2 seconds or more.

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.
NOTE:
CAN communication system is normal if DTC of CAN communication is indicated on SELF-DIAG RESULTS of
CONSULT under the above conditions. Erase the memory of the self-diagnosis of each control unit.

JSMIA0527GB

Component

Description

Main line

CAN communication line between splices

Branch line

CAN communication line between splice and a control unit

Splice

A point connecting a branch line with a main line

Termination circuit

Circuit connected across the CAN communication system. (Resistor)

LAN

TROUBLE DIAGNOSIS

LAN-11

< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

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Symptom When Error Occurs in CAN Communication System

INFOID:0000000009653523

In CAN communication system, multiple control units mutually transmit and receive signals. Each control unit
cannot transmit and receive signals if any error occurs on CAN communication line. Under this condition, mul-
tiple control units related to the root cause malfunction or go into fail-safe mode.

ERROR EXAMPLE

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

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

JSMIA0442GB

Unit name

Major symptom

ECM

Engine torque limiting is affected, and shift harshness increases.

BCM

• Reverse warning buzzer 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.

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.

LAN-12

< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSIS

Example: TCM Branch Line Open Circuit

NOTE:
The model (all control units on CAN communication system are Diag on CAN) cannot perform CAN diagnosis
with CONSULT if the following error occurs. The error is judged by the symptom.

Example: Data Link Connector Branch Line Open Circuit

JSMIA0443GB

Unit name

Major symptom

ECM

Engine torque limiting is affected, and shift harshness increases.

BCM

Reverse warning buzzer does not sound.

EPS control unit

Normal operation.

Combination meter

• Shift position indicator and O/D 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.

Error

Difference of symptom

Data link connector branch line open circuit

Normal operation.

CAN-H, CAN-L harness short-circuit

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

JSMIA0444GB

LAN

TROUBLE DIAGNOSIS

LAN-13

< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

C

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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.

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

CAN Diagnosis with CONSULT

INFOID:0000000009653524

CAN diagnosis on CONSULT extracts the root cause by receiving the following information.

Unit name

Major symptom

ECM

Normal operation.

BCM

EPS control unit

Combination meter

ABS actuator and electric unit (control unit)

TCM

IPDM E/R

JSMIA0445GB

Unit name

Major symptom

ECM

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

BCM

• Reverse warning buzzer 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.