Infiniti Q45. Manual

SYSTEM DESCRIPTION

BRC-9

[VDC/TCS/ABS]

BRC

Hydraulic Circuit Diagram

NFS000CO

CAN Communication

NFS000HJ

SYSTEM DESCRIPTION

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. Refer to

LAN-40, "CAN

Communication Unit"

PFIA0773E

BRC-10

[VDC/TCS/ABS]

TROUBLE DIAGNOSIS

PFP:00004

Fail-Safe Function

NFS000I1

VDC/TCS SYSTEM

In case of VDC/TCS system malfunction, the VDC OFF indicator lamp and SLIP indicator lamp are turned on,
and the condition of the vehicle is the same as the condition of vehicles without VDC/TCS equipment. In case
of electrical malfunction with the VDC/TCS system, the ABS control continues to operate normally without
VDC/TCS control.

CAUTION:

If the Fail-Safe function is activated, then perform the self diagnosis for VDC/TCS/ABS control system.

ABS, EBD SYSTEM

In case of electrical incidents with the ABS, ABS warning lamp, VDC OFF indicator lamp, SLIP indicator lamp
will turn on. In case of electrical incidents with EBD, ABS warning lamp, VDC OFF indicator lamp and SLIP
indicator lamp will turn on. Simultaneously, the VDC/ TCS/ABS become one of the following conditions of the
Fail-Safe function.
1.

For ABS malfunction, only the EBD is activated and the condition of the vehicle is the same condition of
vehicles without VDC/TCS/ABS equipment.

NOTE:
In condition 1 described above, an ABS self diagnosis sound may be heard. That is a normal condition
because a self-diagnosis for “Ignition Switch ON” and “the First Starting” are being performed.

For EBD malfunction, the EBD and ABS become inoperative, and the condition of the vehicle is the same
as the condition of vehicles without VDC/TCS/ABS, EBD equipment.

How to Perform Trouble Diagnosis For Quick and Accurate Repair

NFS000CQ

INTRODUCTION

●

To perform trouble diagnosis it is the most important to have understanding about vehicle system (control
and mechanism) thoroughly.

●

It is also important to clarify customer complaints before inspec-
tion.
First of all, reproduce symptom, and understand it fully.
Ask customer about his/her complaints carefully. In some cases,
it will be necessary to check symptom by driving vehicle with
customer.
NOTE:
Customers are not professionals. Do not assume “maybe cus-
tomer means...” or “maybe customer mentioned this symptom”.

●

It is essential to check symptoms right from beginning in order to
repair a malfunction completely.
For an intermittent malfunction, it is important to reproduce
symptom based on interview with customer and past examples.
Do not perform inspection on ad hoc basis. Most intermittent
malfunctions are caused by poor contacts. In this case, it will be
effective to shake suspected harness or connector by hand.
When repairs are performed without any symptom check, no
one can judge if malfunction has actually been eliminated.

●

After diagnosis, make sure to perform “erase memory”. Refer to

BRC-26, "How to Erase Self-Diagnostic Results"

●

For an intermittent malfunction, move harness or harness con-
nector by hand to check poor contact or false open circuit.

●

Always read “GI section” to confirm general precautions. Refer to

GI-4, "General Precautions"

SEF234G

SEF233G

TROUBLE DIAGNOSIS

BRC-11

[VDC/TCS/ABS]

BRC

DIAGNOSIS FLOW CHART

PFIA0708E

BRC-12

[VDC/TCS/ABS]

TROUBLE DIAGNOSIS

ASKING COMPLAINTS

●

Complaints against malfunction vary depending on each person.
It is important to clarify customer complaints.

●

Ask customer about what symptoms are present and under
what conditions. Use information to reproduce symptom while
driving.

●

It is also important to use diagnosis sheet so as not to miss infor-
mation.

EXAMPLE OF DIAGNOSIS SHEET

SBR339B

SFIA3265E

Infiniti Q45. Manual - part 261