Nissan Ariya: Trouble Diagnosis

Nissan Ariya (FE0) 2023-2025 Service & Repair Manual / Electrical & Power Control / Lan System :: Can Fundamental / Trouble Diagnosis

Component Description
Condition of Error Detection
Symptom When Error Occurs in Can Communication System
Can Diagnosis with Consult
Self-Diagnosis
Network Diagnosis
How to Use Can Communication Signal Chart

Component Description

System Description

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)

Condition of Error Detection

System Description

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 power 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 power 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.

Symptom When Error Occurs in Can Communication System

System Description

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, 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 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

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 wiper 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 power switch is ON, The headlamps (Lo) turn ON. The cooling fan continues to rotate.

Example: TCM Branch Line Open Circuit

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.

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.

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 communication system enter fail-safe mode or are deactivated.

Example: Data Link Connector Branch Line Open Circuit

Unit name	Major symptom
ECM	Normal operation.
BCM
EPS control unit
Combination meter
ABS actuator and electric unit (control unit)
TCM
IPDM E/R

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

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 power switch OFF.) The steering lock does not release (if an error or malfunction occurs while turning the power 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 power switch is ON, The headlamps (Lo) turn ON. The cooling fan continues to rotate.

Can Diagnosis with Consult

System Description

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

Response to the system call
Control unit diagnosis information
Self-diagnosis
Network Diagnosis

Self-Diagnosis

System Description

If communication signals cannot be transmitted or received among control units communicating via CAN communication line, CAN communication-related DTC is displayed on the CONSULT “Self Diagnostic Result” screen.

Network Diagnosis

System Description

When CAN communication error occurs, the estimated malfunction part is displayed in "Network Diagnosis". The malfunction part is identified by referring to the following displays of network and unit, and error cases.

Item	Color	Diagnosis result
Network	Red background	There is an unit where unable communication has occurred.
	Red text	CAN communication error is occurred. (Present error)
	Yellow	CAN communication error was occurred. (Past error)
	Green	No CAN communication error are occurred between the units in the network.
ECU status	Red background	Unable communication
	Red text	CAN communication error is detected by other units. (Present error)
	Yellow	CAN communication error was detected by other units. (Past error)
	Green	The unit is normal. There is error of CAN communication with some units.
	Gray	Normal

ERROR EXAMPLE

Example: Unable Communication for Combination Meter

Item	Description
CONSULT display	One unit with a red background
Work procedure	Perform trouble diagnosis procedure for combination meter.

NOTE:

When unable communication occurs on the another unit, the applicable unit is displayed with a red background.

Example: CAN Communication Error for Main Line Between Combination Meter and TCM

Item	Description
CONSULT display	Some units connected to the main line with red text
Work procedure	Perform diagnosis procedure for main line between combination meter and TCM.

NOTE:

The unit displayed in red text is determined by the mutual communication status.

Example: CAN Communication Error for TCM Branch Line

Item	Description
CONSULT display	One unit with a red text
Work procedure	Perform diagnosis procedure for TCM branch line.

NOTE:

When the branch line communication malfunction of another unit occurs, the unit is displayed in red text.

Example: Unable Communication for Data Link Connector

Item	Description
CONSULT display	All of network and units with red backgrounds
Work procedure	Perform diagnosis procedure for data link connector branch line.

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

Item	Description
CONSULT display	All of units in a network with red backgrounds
Work procedure	Perform diagnosis procedure for the CAN communication circuit.

How to Use Can Communication Signal Chart

System Description

The CAN communication signal chart lists the signals transmitted/received among control units. It is useful for detecting the root cause by finding a signal related to the symptom, and by checking transmission and reception unit.