Air INFINITI QX56 2004 Factory Service Manual

PRECAUTIONS
BRC-5
[VDC/TCS/ABS]
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Area to be repaired must be soldered and wrapped with tape.
Make sure that fraying of twisted wire is within 110 mm (4.33 in).

Do not make a bypass connection to repaired area. (If the circuit
is bypassed, characteristics of twisted wire will be lost.)
Wiring Diagrams and Trouble Diagnosis EF S0 03 QF
When you read wiring diagrams, refer to the following:

GI-15, "How to Read Wiring Diagrams".

PG-4, "POWER SUPPLY ROUTING CIRCUIT".
When you perform trouble diagnosis, refer to the following:

GI-11, "HOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSES".

GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident".
PKIA0306E
PKIA0307E

TROUBLE DIAGNOSIS
BRC-11
[VDC/TCS/ABS]
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TROUBLE DIAGNOSISPFP:00000
How to Perform Trouble Diagnoses for Quick and Accurate RepairEFS003QQ
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

TROUBLE DIAGNOSIS
BRC-29
[VDC/TCS/ABS]
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6. Select the required diagnostic location from the “SELECT DIAG
MODE” screen.
For further information, see the CONSULT-II Operation Manual.
SELF-DIAGNOSIS
Description
If an error is detected in the system, the ABS warning lamp will turn on. In this case, perform self-diagnosis as
follows:
Operation Procedure
1. Turn ignition switch OFF.
2. Connect CONSULT-II and CONSULT-II CONVERTER to the data link connector.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
3. Turn ignition switch ON.
4. Start engine and drive at approximately 30 km/h (19 MPH) or more for approximately 1 minute.
5. After stopping the vehicle, with the engine running, touch “START (NISSAN BASED VHCL)”, “ABS”,
“SELF-DIAG RESULTS” in order on the CONSULT-II screen.
CAUTION:
If “START (NISSAN BASED VHCL)” is touched immediately after starting the engine or turning on
the ignition switch, “ABS” might not be displayed in the Select System screen. In this case, repeat
the operation from step 1.
6. The self-diagnostic results are displayed. (If necessary, the self-diagnostic results can be printed out by
touching “PRINT”.)

When “NO DTC IS DETECTED” is displayed, check the ABS warning lamp, SLIP indicator lamp and
VDC OFF indicator lamp.
7. Conduct the appropriate inspection from the display item list, and repair or replace the malfunctioning
component.
8. Start engine and drive at approximately 30 km/h (19 MPH) or more for approximately 1 minute.
CAUTION:

When a wheel sensor “short-circuit” is detected, if the vehicle is not driven at 30 km/h (19 MPH)
for at least 1 minute, the ABS warning lamp will not turn off even if the malfunction is repaired.
9. Turn ignition switch OFF to prepare for erasing the memory.
10. Start the engine and touch “START (NISSAN BASED VHCL)”, “ABS”, “SELF-DIAG RESULTS”, “ERASE”
in order on the CONSULT-II screen to erase the error memory.
If “ABS” is not indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC) Circuit" .
CAUTION:
If the error memory is not erased, re-conduct the operation from step 5.
11. For the final inspection, drive at approximately 30 km/h (19 MPH) or more for approximately 1 minute and
confirm that the ABS warning lamp, SLIP indicator lamp, and VDC OFF indicator lamp are off.
BCIA0031E

BRC-36
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
ACTIVE TEST
CAUTION:

Do not perform active test while driving.

Make sure to completely bleed air from the brake system.

The ABS and brake (EBD) warning lamps turn on during the active test.
Operation Procedure
1. Connect the CONSULT-II and CONSULT-II CONVERTER to the data link connector and start the engine.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
2. Touch “START (NISSAN BASED VHCL) ” on the display screen.
3. Touch “ABS”.
If “ABS” is not indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC) Circuit" .
4. Touch “ACTIVE TEST”.
5. The test item selection screen is displayed.
6. Touch necessary test item.
7. With the “MAIN SIGNALS” display selected, touch “START”.
8. The Active Test screen will be displayed, so conduct the following test.
Solenoid Valve Operation Chart
*: ON for 1 to 2 seconds after the touch, and then OFF
NOTE:

If active test is performed with brake pedal depressed, pedal stroke may change. This is normal.

“TEST IS STOPPED” is displayed approximately 10 seconds after operation starts.

After “TEST IS STOPPED” is displayed, to perform test again, repeat Step 6.
LBR379
OperationABS solenoid valve ABS solenoid valve (ACT)
UP KEEP DOWN UPACTUA-
TO R U PACTUA-
TOR KEEP
FR RH SOL
FR RH ABS SOLE-
NOID (ACT)FR RH IN SOL OFF ON ON OFF OFF OFF
FR RH OUT SOL OFF OFF ON* OFF OFF OFF
FR LH SOL
FR LH ABS SOLE-
NOID (ACT)FR LH IN SOL OFF ON ON OFF OFF OFF
FR LH OUT SOL OFF OFF ON* OFF OFF OFF
RR RH SOL
RR RH ABS SOLE-
NOID (ACT)RR RH IN SOL OFF ON ON OFF OFF OFF
RR RH OUT SOL OFF OFF ON* OFF OFF OFF
RR LH SOL
RR LH ABS SOLE-
NOID (ACT)RR LH IN SOL OFF ON ON OFF OFF OFF
RR LH OUT SOL OFF OFF ON* OFF OFF OFF
REAR SOLRR RH IN SOL OFF ON ON OFF OFF OFF
RR RH OUT SOL OFF OFF ON* OFF OFF OFF
RR LH IN SOL OFF ON ON OFF OFF OFF
RR LH OUT SOL OFF OFF ON* OFF OFF OFF

BRC-38
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 QX56
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMSPFP:00000
Wheel Sensor System InspectionEFS003QY
INSPECTION PROCEDURE
1. CONNECTOR INSPECTION
Disconnect the ABS actuator and electric unit (control unit) connector E125 and wheel sensor of malfunction-
ing code.
Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace as necessary.
2. CHECK WHEEL SENSOR OUTPUT SIGNAL
1. Connect ABS active wheel sensor tester (J-45741) to wheel sensor using appropriate adapter.
2. Turn on the ABS active wheel sensor tester power switch.
NOTE:
The green POWER indicator should illuminate. If the POWER indicator does not illuminate, replace the
battery in the ABS active wheel sensor tester before proceeding.
3. Spin the wheel of the vehicle by hand and observe the red SENSOR indicator on the ABS active wheel
sensor tester. The red SENSOR indicator should flash on and off to indicate an output signal.
NOTE:
If the red SENSOR indicator illuminates but does not flash, reverse the polarity of the tester leads and
retest.
Does the ABS active wheel sensor tester detect a signal?
Yes >> GO TO 3.
No >> Replace the wheel sensor. Refer to BRC-64, "
Removal and Installation" .
3. CHECK TIRES
Check for inflation pressure, wear and size of each tire.
Are tire pressure and size correct and is tire wear within specifications?
Yes >> GO TO 4.
No >> Adjust tire pressure or replace tire(s).
4. CHECK WHEEL BEARINGS
Check wheel bearing axial end play. Refer to FAX-5, "
WHEEL BEARING INSPECTION" or RAX-5, "WHEEL
BEARING INSPECTION" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace as necessary. Refer to FAX-5, "
WHEEL BEARING INSPECTION" or RAX-5,
"WHEEL BEARING INSPECTION" .
5. CHECK WIRING HARNESS FOR SHORT CIRCUIT
1. Disconnect ABS actuator and electric unit (control unit) connec-
tor and wheel sensor connector of malfunction code No.
2. Check resistance between wheel sensor harness connector ter-
minals and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair the circuit.Continuity should not exist.
WFIA0192E

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
BRC-39
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6. CHECK WIRING HARNESS FOR OPEN CIRCUIT
1. Check continuity between ABS actuator and electric unit (control unit) harness connector E125 and the
malfunctioning wheel sensor harness connector E18, E117, C10, or C11.
OK or NG
OK >> Replace the ABS actuator and electric unit (control unit). Refer to BRC-66, "Removal and Installa-
tion" .
NG >> Repair the circuit.
Engine System InspectionEF S0 03 QZ
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
Yes >> GO TO 2.
No >> Inspection End.
2. ENGINE SYSTEM INSPECTION
1. Perform ECM self-diagnosis and repair as necessary.
2. Perform ABS actuator and electric unit (control unit) self-diagnosis again.
OK or NG
OK >> Inspection End.
NG >> Repair or replace as necessary.
Wheel sensorABS actuator and
electric unit (control unit)Wheel sensor
Continuity
Connector - terminal Wire color Connector - terminal Wire color
Front LHE125 - 45 G/O E18 - 1 G/O
Ye s E125 - 46 BR/W E18 - 2 BR/W
Front RHE125 - 34 B/R E117 - 1 B/R
E125 - 33 BR E117 - 2 BR
Rear LHE125 - 37 P C11 - DS P
E125 - 36 L C11 - DP L
Rear RHE125 - 42 V C10 - DS V
E125 - 43 G/Y C10 - DP G/Y
Continuity should exist.
Self-diagnosis results
ENGINE SIGNAL 1
ENGINE SIGNAL 2
ENGINE SIGNAL 3
ENGINE SIGNAL 4
ENGINE SIGNAL 6

BRC-40
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 QX56
ABS/TCS/VDC Control Unit InspectionEFS003R0
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
Yes >> Replace ABS actuator and electric unit (control unit). Refer to BRC-66, "Removal and Installation"
.
No >> Inspection End.
Steering Angle Sensor SystemEFS003R1
INSPECTION PROCEDURE
1. CHECK SELF-DIAGNOSIS RESULT
Check self-diagnosis results.
Is above displayed in self-diagnosis item?
YES >> GO TO 2.
NO >> Inspection End.
2. CHECK CONNECTOR
1. Disconnect steering angle sensor connector M47 and ABS actuator and electric unit (control unit) connec-
tor E125 and check terminals for deformation, disconnection, looseness, or damage. Repair or replace as
necessary.
2. Reconnect connectors and repeat ABS actuator and electric unit (control unit) self-diagnosis.
IS "ST ANGLE SEN CIRCUIT" or "ST ANG SEN COM CIR" DISPLAYED?
YES >> GO TO 3.
NO >> Inspection End.
Self-diagnosis results
CONTROLLER FAILURE
VARIANT CODING
Self-diagnosis results
ST ANGLE SEN CIRCUIT
ST ANG SEN COM CIR

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
BRC-41
[VDC/TCS/ABS]
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3. CHECK STEERING ANGLE SENSOR HARNESS
1. Check CAN communication system. Refer to LAN-5, "
CAN COMMUNICATION" .
2. Turn ignition switch OFF and disconnect steering angle sensor
connector M47 and ABS actuator and electric unit (control unit)
connector E125.
3. Check continuity between ABS actuator and electric unit (control
unit) connector E125 and steering angle sensor connector M47.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace harness.
4. CHECK DATA MONITOR
1. Connect steering angle sensor and ABS actuator and electric unit (control unit) connectors.
2. Use “DATA MONITOR” to check if the status of "STR ANGLE SIG" is normal.
OK or NG
OK >> Perform ABS actuator and electric unit (control unit) self-diagnosis again.
NG >> Replace spiral cable (steering angle sensor) and adjust neutral position of steering angle sensor.
Refer to BRC-62, "
Adjustment of Steering Angle Sensor Neutral Position" .
Yaw Rate/Side/Decel G Sensor System InspectionEFS003R2
CAUTION:
Sudden turns (such as spin turns, acceleration turns), drifting, etc. when VDC function is OFF may
cause the yaw rate/side/decel G sensor system to indicate a problem. This is not a problem if normal
operation can be resumed after restarting the engine.
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
CAUTION:
If vehicle is on turn table at entrance to parking garage, or on other moving surface, VDC OFF indica-
tor lamp may illuminate and CONSULT-II self-diagnosis may indicate yaw rate sensor system malfunc-ABS actuator and
electric unit (control
unit) harness connec-
tor E125Steering angle
sensor
harness connec-
tor M47Continuity
11 ( W ) 3 (W ) Yes
15 (R) 4 (R) Yes
WFIA0224E
Steering condition Data monitor
Straight-ahead –3.5 deg to +3.5 deg
Turn wheel to the right by 90°Approx. - 90deg
Turn wheel to the left by 90°Approx. + 90deg
Self-diagnosis results
YAW R AT E S E N S O R
SIDE G-SEN CIRCUIT
G-SENSOR

BRC-42
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 QX56
tion. However, in this case there is no malfunction in yaw rate sensor system. Take vehicle off of turn
table or other moving surface, and start engine. Results will return to normal.
Is the above displayed in the self-diagnosis display items?
Yes >> GO TO 2.
No >> Inspection End.
2. CONNECTOR INSPECTION
Disconnect the ABS actuator and electric unit (control unit) connector E125 and yaw rate/side/decel G sensor
connector M108.
Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace as necessary.
3. YAW RATE/SIDE/DECEL G SENSOR HARNESS INSPECTION
1. Turn off the ignition switch and disconnect yaw rate/side/decel G sensor connector M108 and ABS actua-
tor and electric unit (control unit) connector E125.
2. Check continuity between the ABS actuator and electric unit (control unit) connector E125 and the yaw
rate/side/decel G sensor connector M108.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace as necessary.
4. YAW RATE/SIDE/DECEL G SENSOR INSPECTION
1. Connect the yaw rate/side/decel G sensor connector M108 and ABS actuator and electric unit (control
unit) connector E125.
2. Use “DATA MONITOR” to check if the yaw rate/side/decel G sensor signals are normal.
OK or NG
OK >> Inspection End.
NG >> Replace the yaw rate/side/decel G sensor. Refer to BRC-69, "
Removal and Installation" . ABS actuator and electric unit
(control unit) harness connector
E125Yaw rate/side/decel G sensor
harness connector M108 Continuity
6 (Y/R) 3 (Y/R) Yes
24 (P) 5 (P) Yes
25 (G/R) 1 (G/R) Yes
29 (G/W) 2 (G/W) Yes
Vehicle statusYaw rate sensor
(Data monitor standard)Side G sensor
(Data monitor standard)Decel G Sensor
(Data monitor standard)
When stopped -4 to +4 deg/s -1.1 to +1.1 m/s -0.11 G to +0.11 G
Right turn Negative value Negative value -
Left turn Positive value Positive value -
Speed up - - Negative value
Speed down - - Positive value

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
BRC-43
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Solenoid and VDC Change-Over Valve System InspectionEFS003R3
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
Yes >> GO TO 2.
No >> Inspection End.
2. CONNECTOR INSPECTION
1. Disconnect ABS actuator and electric unit (control unit) connector E125.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace as necessary.
Self-diagnosis results
FR LH IN ABS SOL
FR LH OUT ABS SOL
RR RH IN ABS SOL
RR RH OUT ABS SOL
FR RH IN ABS SOL
FR RH OUT ABS SOL
RR LH IN ABS SOL
RR LH OUT ABS SOL
CV 1
CV 2
SV 1
SV 2