Nissan Versa Sedan. Manual — part 532

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< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

SYSTEM

SYSTEM DESCRIPTION

SYSTEM

CAN COMMUNICATION SYSTEM
CAN COMMUNICATION SYSTEM : System Description

INFOID:0000000009269334

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.

DIAG ON CAN
DIAG ON CAN : System Description

INFOID:0000000009269335

SYSTEM DIAGRAM

JSMIA0526GB

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SYSTEM

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< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

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DESCRIPTION

“Diag on CAN” is a diagnosis method which uses the CAN communication line for the communication between

the control unit and the diagnostic tool.

Name

Harness

Description

DDL1

Tx
Rx

For communications with the diagnostic tool. (CAN-H and CAN-L are used for control-
ling)

DDL2

K-LINE

For communications with the diagnostic tool. (CAN-H and CAN-L are used for control-
ling)

Diag on CAN

CAN-H
CAN-L

For communications with the diagnostic tool. (CAN-H and CAN-L are also used for con-
trol and diagnoses.)

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< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSIS

TROUBLE DIAGNOSIS

Component Description

INFOID:0000000009269336

Condition of Error Detection

INFOID:0000000009269337

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)

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TROUBLE DIAGNOSIS

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< SYSTEM DESCRIPTION >

[CAN FUNDAMENTAL]

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Symptom When Error Occurs in CAN Communication System

INFOID:0000000009269338

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.