INFINITI QX4 2005 Factory Service Manual

BRC-10
[VDC/TCS/ABS]
CAN COMMUNICATION
Revision: October 20052005 QX56
CAN COMMUNICATIONPFP:23710
System DescriptionEFS004XI
Refer to LAN-5, "CAN COMMUNICATION" .

TROUBLE DIAGNOSIS
BRC-11
[VDC/TCS/ABS]
C
D
E
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BRC
Revision: October 20052005 QX56
TROUBLE DIAGNOSISPFP:00000
How to Perform Trouble Diagnoses for Quick and Accurate RepairEFS004XJ
INTRODUCTION
The ABS/TCS/VDC system has an electronic control unit to control
major functions. The control unit accepts input signals from sensors
and controls actuator operation. It is also important to check for con-
ventional problems such as air leaks in the booster or lines, lack of
brake fluid, or other problems with the brake system.
It is much more difficult to diagnose a problem that occurs intermit-
tently rather than continuously. Most intermittent problems are
caused by poor electrical connections or faulty wiring. In this case,
careful checking of suspicious circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the problem, so a road
test should be performed.
Before undertaking actual checks, take just a few minutes to talk with
a customer who approaches with an ABS/TCS/VDC complaint. The
customer is a very good source of information on such problems,
especially intermittent ones. Through the talks with the customer,
find out what symptoms are present and under what conditions they
occur.
Start your diagnosis by looking for “conventional” problems first. This
is one of the best ways to troubleshoot brake problems on an ABS/
TCS/VDC equipped vehicle. Also check related Service Bulletins for
information.
SEF 2 33 G
SEF 2 34 G

BRC-12
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
WORK FLOW
WFIA0358E

TROUBLE DIAGNOSIS
BRC-13
[VDC/TCS/ABS]
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BRC
Revision: October 20052005 QX56
CLARIFY CONCERN

A customer's description of a vehicle concern may vary depend-
ing on the individual. It is important to clarify the customer's con-
cern.

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

It is also important to use the diagnosis sheet to understand
what type of trouble the customer is having.
EXAMPLE OF DIAGNOSIS SHEET
SBR3 39 B
WFIA0097E

BRC-14
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Component Parts and Harness Connector LocationEFS004XK
WFIA0370E

TROUBLE DIAGNOSIS
BRC-15
[VDC/TCS/ABS]
C
D
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MA
B
BRC
Revision: October 20052005 QX56
SchematicEFS004XL
WFWA0182E

BRC-16
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Wiring Diagram — VDC —EFS004XM
WFWA0183E

TROUBLE DIAGNOSIS
BRC-17
[VDC/TCS/ABS]
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BRC
Revision: October 20052005 QX56
WFWA0184E

BRC-18
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
WFWA0185E

TROUBLE DIAGNOSIS
BRC-19
[VDC/TCS/ABS]
C
D
E
G
H
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J
K
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MA
B
BRC
Revision: October 20052005 QX56
WFWA0186E