Infiniti M35/M45 Y50. Manual - part 839

SYSTEM DESCRIPTION

LAN-5

[CAN FUNDAMENTAL]

C

D

E

F

G

H

I

J

L

M

A

B

LAN

CAN COMMUNICATION CONTROL CIRCUIT

*: These are the only control units wired with both ends of CAN communication system.

SKIB8713E

Component

System description

CAN controller

It controls CAN communication signal transmission and reception, error detection, etc.

Transceiver IC

It converts digital signal into CAN communication signal, and CAN communication signal into digi-
tal signal.

Noise filter

It eliminates noise of CAN communication signal.

Termination circuit

*

(Resistance of approx. 120 

Ω

)

It produces potential difference.

LAN-6

[CAN FUNDAMENTAL]

SYSTEM DESCRIPTION

Diag on CAN

NKS004HB

DESCRIPTION

“Diag on CAN” is a diagnosis using CAN communication instead of previous DDL1 and DDL2 communication
lines, between control units and diagnosis unit.

SYSTEM DIAGRAM

SKIB8714E

Name

Harness

Description

DDL1

Tx
Rx

It is used for trouble diagnosis. (CAN-H and CAN-L are used for controlling)

DDL2

K-LINE

It is used for trouble diagnosis. (CAN-H and CAN-L are used for controlling)

Diag on CAN

CAN-H
CAN-L

It is used for trouble diagnosis and control.

TROUBLE DIAGNOSIS

LAN-7

[CAN FUNDAMENTAL]

C

D

E

F

G

H

I

J

L

M

A

B

LAN

TROUBLE DIAGNOSIS

PFP:00004

Condition of Error Detection

NKS004HC

“U1000” or “U1001” is indicated on SELF-DIAG RESULTS on CONSULT-II if 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 “U1000” OR “U1001” IS INDICATED EVEN THOUGH CAN COMMUNICATION SYSTEM 
IS NORMAL

●

CONSULT-II CONVERTER not connected: Error may be detected by the self-diagnosis when not using
CONSULT-II CONVERTER (Depending on the control unit which carries out CAN communication).

●

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 communica-
tion, 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 “U1000” or “U1001” is indicated on SELF-DIAG RESULTS of CON-
SULT-II under the above conditions. Erase the memory of the self-diagnosis of each unit.

LAN-8

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSIS

Symptom When Error Occurs in CAN Communication System

NKS004HD

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-41, "Abbreviation List"

  for the unit abbreviation.

Example: TCM 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.