brake fluid INFINITI QX56 2004 Factory Manual PDF

TROUBLE DIAGNOSIS
BRC-11
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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-23
[VDC/TCS/ABS]
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Basic InspectionEFS003QU
BRAKE FLUID LEVEL, FLUID LEAK, AND BRAKE PAD INSPECTION
1. Check fluid level in the brake fluid reservoir. If fluid level is low, add fluid.
2. Check the brake piping and around the ABS actuator and electric unit (control unit) for leaks. If there is
leaking or seeping fluid, check the following items.

If ABS actuator and electric unit (control unit) connection is loose, tighten the piping to the specified
torque and recheck for leaks.

If there is damage to the connection flare nut or ABS actuator and electric unit (control unit) threads,
replace the damaged part and recheck for leaks.

When there is fluid leaking or seeping from a fluid connection, use a clean cloth to wipe off the fluid and
recheck for leaks. If fluid is still seeping out, replace the damaged part. If the fluid is leaking at the ABS
actuator and electric unit (control unit), replace the ABS actuator and electric unit (control unit) assem-
bly.
CAUTION:
The ABS actuator and electric unit (control unit) cannot be disassembled and must be replaced
as an assembly.
3. Check the brake pads for excessive wear.
POWER SYSTEM TERMINAL LOOSENESS AND BATTERY INSPECTION
Make sure the battery positive cable, negative cable and ground connection are not loose. In addition, make
sure the battery is sufficiently charged.
ABS WARNING LAMP, SLIP INDICATOR LAMP AND VDC OFF INDICATOR LAMP INSPECTION
1. Make sure ABS warning lamp, SLIP indicator lamp and VDC OFF indicator lamp (when VDC OFF switch
is off), turn on for approximately 2 seconds when the ignition switch is turned ON. If they do not, check the
VDC OFF indicator lamp and the VDC OFF switch. Refer to BRC-56, "
VDC OFF SWITCH" . Check CAN
communications. If there are no errors with the VDC OFF switch or CAN communication system, check
combination meter. Refer to DI-5, "
COMBINATION METERS" .
2. Make sure the lamps turn off approximately 2 seconds after the ignition switch is turned ON. If the lamp
does not turn off, conduct self-diagnosis.
3. With the engine running, make sure the VDC OFF indicator lamp turns on and off when the VDC OFF
switch is turned on and off. If the indicator lamp status does not correspond to switch operation, check the
VDC OFF switch. Refer to BRC-56, "
VDC OFF SWITCH" .
4. Make sure ABS warning lamp, SLIP indicator lamp and VDC OFF indicator lamp turn off approximately 2
seconds after the engine is started. If ABS warning lamp, SLIP indicator lamp or VDC OFF indicator lamp
have not turned off 10 seconds after the engine has been started, conduct self-diagnosis of the ABS actu-
ator and electric unit (control unit).
5. After conducting the self-diagnosis, be sure to erase the error memory. Refer to BRC-28, "
CONSULT-II
Function (ABS)" .

BRC-26
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Note 1: Confirm tire pressure is normal.
Note 2: ON/OFF timing of ABS warning lamp
ON: For approximately 2 seconds after ignition switch is turned ON, or when a malfunction is detected.
OFF: Approximately 2 seconds after ignition switch is turned ON (when system is in normal operation) and TCS/VDC function is not
activated.
Note 3: ON/OFF timing of VDC OFF indicator lamp
ON: For approximately 2 seconds after ignition switch is turned ON, or when a malfunction is detected and VDC OFF switch is ON.
OFF: Approximately 2 seconds after ignition switch is turned ON (when system is in normal operation.) And when VDC OFF switch is
OFF.
Note 4: SLIP indicator lamp ON/OFF timing
ON: For approximately 2 seconds after ignition switch is turned ON, or when a malfunction is detected and TCS/VDC function is acti-
vated while driving.FR LH IN SOL
FR LH OUT SOL
FR RH IN SOL
FR RH OUT SOL
RR RH IN SOL
RR RH OUT SOL
RR LH IN SOL
RR LH OUT SOLSolenoid valve opera-
tionActuator (solenoid) is active
(“ACTIVE TEST” with CON-
SULT-II) or actuator relay is
inactive (in fail-safe mode).ON
BRC-43, "
Solenoid and
VDC Change-Over Valve
System Inspection"
When actuator (solenoid) is
not active and actuator relay is
active (ignition switch ON).OFF
CV1
CV2
SV1
SV2VDC switch-over valve
statusWhen actuator (switch-over
valve) is active (“ACTIVE
TEST” with CONSULT-II) or
actuator relay is inactive (when
in fail-safe mode).ON
When actuator (switch-over
valve) is not active and actua-
tor relay is active (ignition
switch ON).OFF
DECEL G-SENLongitudinal accelera-
tion detected by Decel
G-SensorVehicle stopped Approx. 0 GBRC-41, "
Ya w R a te / S i d e /
Decel G Sensor System
Inspection"Vehicle running -1.7 to 1.7 G
PRESS SENSORBrake fluid pressure
detected by pressure
sensorDo not step on the Brake pedal
(When ignition switch is ON)Approx. 0 bar
—
Step on the Brake pedal
(When ignition switch is ON)-40 to 300 bar
FLUID LEV SWON/OFF status of
brake fluid level switchWhen brake fluid level switch
ONON
DI-31, "
WAR NIN G
LAMPS"When brake fluid level switch
OFF OFF
VDC SIGNAL
TCS SIGNAL
ABS SIGNAL
EBD SIGNALSignal statusVDC active
TCS active
ABS active
EBD activeON
VDC system
TCS system
ABS system
EBD system VDC not active
TCS not active
ABS not active
EBD not activeOFF
VDC FAIL SIG
TCS FAIL SIG
ABS FAIL SIG
EBD FAIL SIGFail signal statusVDC fail
TCS fail
ABS fail
EBD failON
VDC system
TCS system
ABS system
EBD system VDC normal
TCS normal
ABS normal
EBD normalOFF Monitor item Display contentData monitor
Note: Error inspection
checklist
ConditionReference value in
normal operation

BRC-32
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Note 1. If wheel sensor 2 for each wheel is indicated, check ABS actuator and electric unit (control unit) power
supply voltage in addition to wheel sensor circuit check.
Note 2. If multiple malfunctions are detected including CAN communication line [U1000], perform diagnosis for
CAN communication line first.
Note 3: "ACTUATOR RLY" on the CONSULT-II self-diagnosis results indicates the malfunction of the actuator
motor relay or circuit.
DATA MONITOR
Operation Procedure
1. After turning OFF the ignition switch, connect CONSULT-II and the CONSULT-II CONVERTER to the data
link connector.
SIDE G-SEN CIRCUIT
[C1146]Lateral G-sensor is malfunctioning, or signal line of lateral G-sen-
sor is open or shorted.BRC-41, "Ya w R a t e /
Side/Decel G Sensor
System Inspection"
BR FLUID LEVEL LOW
[C1155]Brake fluid level drops or circuit between ABS actuator and elec-
tric unit (control unit) and brake fluid level switch is open or
shorted.BRC-47, "Brake Fluid
Level Switch System
Inspection"
ENGINE SIGNAL 1
[C1130]Based on the signal from ECM, ABS actuator and electric unit
(control unit) judges that engine fuel cut system is malfunction-
ing.
BRC-39, "
Engine Sys-
tem Inspection"
ENGINE SIGNAL 2
[C1131]Based on the signal from ECM, ABS actuator and electric unit
(control unit) judges that engine fuel cut system is malfunction-
ing.
ENGINE SIGNAL 3
[C1132]Based on the signal from ECM, ABS actuator and electric unit
(control unit) judges that engine fuel cut system is malfunction-
ing.
ENGINE SIGNAL 4
[C1133]Based on the signal from ECM, ABS actuator and electric unit
(control unit) judges that engine fuel cut system is malfunction-
ing.
ENGINE SIGNAL 6
[C1136]Based on the signal from ECM, ABS actuator and electric unit
(control unit) judges that engine fuel cut system is malfunction-
ing.
ACTUATOR RLY
[C1140]ABS actuator relay or circuit malfunction.BRC-44, "
Actuator
Motor, Motor Relay, and
Circuit Inspection"
PRESS SEN CIRCUIT
[C1142]ABS pressure sensor circuit malfunction.BRC-51, "Pressure Sen-
sor System Inspection"
VARIANT CODING
[C1170]V coding is not malfunctioning.BRC-40, "ABS/TCS/
VDC Control Unit
Inspection"
ACTIVE BOOSTER SOLENOID
NG
[C1178]Active booster solenoid is malfunctioning, or signal line of active
booster servo is open or shorted.BRC-48, "Active Booster
System Inspection"
DELTA S SEN NG
[C1179]Delta stroke sensor malfunctioning, or signal line of delta stroke
sensor is open or shorted.BRC-49, "Delta Stroke
Sensor System Inspec-
tion"
ACTIVE BOOSTER RESPONSE
NG
[C1181]Active booster response is malfunctioning, or signal line of active
booster response is open or shorted.
BRC-48, "
Active Booster
System Inspection"BRAKE RELEASE SW NG
[C1184]Brake release switch is malfunctioning, or signal line of brake
release switch is open or shorted.
ACC CU INTERNAL NG
[C1185]ICC control unit circuit malfunction.BRC-54, "
ICC System
Inspection"
BRAKE BOOSTER DEFECT
[C1189]Brake booster is defective or malfunctioning.BRC-48, "Active Booster
System Inspection"
Self-diagnostic item Malfunction detecting condition Check system

BRC-34
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
SLIP LAMP
(ON/OFF)–××SLIP indicator lamp (ON/OFF) sta-
tus is displayed.
FR LH IN SOL
(ON/OFF)–××Front LH IN ABS solenoid (ON/
OFF) status is displayed.
FR LH OUT SOL
(ON/OFF)–××Front LH OUT ABS solenoid (ON/
OFF) status is displayed.
RR RH IN SOL
(ON/OFF)–××Rear RH IN ABS solenoid (ON/
OFF) status is displayed.
RR RH OUT SOL
(ON/OFF) –××Rear RH OUT ABS solenoid (ON/
OFF) status is displayed.
FR RH IN SOL
(ON/OFF)–××Front RH IN ABS solenoid (ON/
OFF) status is displayed.
FR RH OUT SOL
(ON/OFF)–××Front RH OUT ABS solenoid (ON/
OFF) status is displayed.
RR LH IN SOL
(ON/OFF)–××Rear LH IN ABS solenoid (ON/
OFF) status is displayed.
RR LH OUT SOL
(ON/OFF)–××Rear LH OUT ABS solenoid (ON/
OFF) status is displayed.
OFF LAMP
(ON/OFF)–××OFF Lamp (ON/OFF) status is dis-
played.
MOTOR RELAY
(ON/OFF)–××ABS motor relay signal (ON/OFF)
status is displayed.
ACTUATOR RLY
(ON/OFF)– ××ABS actuator relay signal (ON/
OFF) status is displayed.
CV1
(ON/OFF)––×Front side switch-over solenoid
valve (cut valve) (ON/OFF) status is
displayed.
CV2
(ON/OFF)––×Rear side switch-over solenoid
valve (cut-valve) (ON/OFF) status
is displayed.
SV1
(ON/OFF)––×Front side switch-over solenoid
valve (suction valve) (ON/OFF) sta-
tus is displayed.
SV2
(ON/OFF)––×Rear side switch-over solenoid
valve (suction valve) (ON/OFF) sta-
tus is displayed.
VDC FAIL SIG
(ON/OFF)––×VDC fail signal (ON/OFF) status is
displayed.
TCS FAIL SIG
(ON/OFF)––×TCS fail signal (ON/OFF) status is
displayed.
ABS FAIL SIG
(ON/OFF)––×ABS fail signal (ON/OFF) status is
displayed.
EBD FAIL SIG
(ON/OFF)––×EBD fail signal (ON/OFF) status is
displayed.
FLUID LEV SW
(ON/OFF)×–×Brake fluid level switch (ON/OFF)
status is displayed.
EBD SIGNAL
(ON/OFF)––×EBD operation (ON/OFF) status is
displayed.
ABS SIGNAL
(ON/OFF)––×ABS operation (ON/OFF) status is
displayed.
TCS SIGNAL
(ON/OFF)––×TCS operation (ON/OFF) status is
displayed. Item
(Unit)Data monitor item selection
Remarks
ECU INPUT
SIGNALSMAIN
SIGNALSSELECTION
FROM MENU

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
BRC-47
[VDC/TCS/ABS]
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3. ABS/TCS/VDC CONTROL UNIT POWER AND GROUND CIRCUIT INSPECTION
Measure the voltage and continuity between the ABS actuator and electric unit (control unit) harness connec-
tor E125 and body ground.
OK or NG
OK >> Check the battery for loose terminals, low voltage, etc. Repair as necessary.
NG >> Repair the circuit.
Brake Fluid Level Switch System InspectionEFS003R7
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
1. Check the brake reservoir tank fluid level. If the level is low, add brake fluid.
2. Erase the self-diagnosis results and check the 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 the ABS actuator and electric unit (control unit) connector E125 and brake fluid level switch
connector E21.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace as necessary.
3. CHECK THE HARNESS BETWEEN THE BRAKE FLUID LEVEL SWITCH AND THE ABS ACTUATOR
AND ELECTRIC UNIT (CONTROL UNIT)
Check the continuity between the brake fluid level switch harness connector E21 and the ABS actuator and
electric unit (control unit) harness connector E125.
OK or NG
OK >> GO TO 4.
NG >> Repair the circuit.Signal nameABS actuator and electric unit
(control unit)
harness connector E125Body
groundMeasured value
Power supply1 (Y)
— Battery voltage (Approx. 12V)
32 (B/Y)
Ground16 (B)
— Continuity should exist.
47 (B)
Self-diagnosis results
BR FLUID LEVEL LOW
ABS actuator and electric unit
(control unit) harness connector
E125Brake fluid level switch harness
connector E21Continuity
8 (P/B) + (P/B) Yes
8 (P/B) Ground No
Ground - (B) Yes

BRC-48
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 QX56
4. CHECK BRAKE FLUID LEVEL SWITCH
Check continuity between brake fluid level switch terminals + and -.
OK or NG
OK >> Perform self-diagnosis again. If the same results appear, replace ABS actuator and electric unit
(control unit). Refer to BRC-66, "
Removal and Installation" .
NG >> Replace brake fluid level switch.
Active Booster System InspectionEFS003R8
INSPECTION PROCEDURE
1. DISPLAY SELF DIAGNOSIS RESULTS
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. Turn the ignition switch OFF.
2. Disconnect the active booster connector E49 and ABS actuator and electric unit (control unit) connector
E125 and inspect the terminals for deformation, disconnection, looseness, or damage.
OK or NG
OK >> GO TO 3.
NG >> Repair connector.Continuity should not exist.
Self-diagnosis results
ACTIVE BOOSTER SOLENOID NG
ACTIVE BOOSTER RESPONSE NG
BRAKE RELEASE SWITCH NG
BRAKE BOOSTER DEFECT

TROUBLE DIAGNOSES FOR SYMPTOMS
BRC-57
[VDC/TCS/ABS]
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TROUBLE DIAGNOSES FOR SYMPTOMSPFP:99999
ABS Works FrequentlyEFS0044T
1. CHECK WARNING LAMP ACTIVATION
Make sure warning lamp remains off while driving.
OK or NG
OK >> GO TO 2.
NG >> Carry out self-diagnosis. Refer to BRC-29, "
SELF-DIAGNOSIS" .
2. CHECK WHEEL SENSORS
Check the following.

Wheel sensor mounting for looseness

Wheel sensors for physical damage

Wheel sensor connectors for terminal damage or loose connections
OK or NG
OK >> GO TO 3.
NG >> Repair or replace as necessary.
3. CHECK FRONT AND REAR AXLES
Check front and rear axles for excessive looseness. Refer to FAX-5, "
WHEEL HUB" or RAX-5, "WHEEL
HUB" .
OK or NG
OK >> GO TO 4.
NG >> Repair as necessary.
4. CHECK BRAKE FLUID PRESSURE
Check brake fluid pressure distribution.
Refer to BRC-23, "
Basic Inspection" .
Is brake fluid pressure distribution normal?
YES >> Inspection End.
NO >> Perform Basic Inspection. Refer to BRC-23, "
Basic Inspection" .

BRC-66
[VDC/TCS/ABS]
ACTUATOR AND ELECTRIC UNIT (ASSEMBLY)
Revision: August 20072004 QX56
ACTUATOR AND ELECTRIC UNIT (ASSEMBLY)PFP:47660
Removal and InstallationEFS003RQ
REMOVAL
1. Disconnect the negative battery terminal.
2. Remove the cowl top extension. Refer to EI-18, "
Removal and Installation" .
3. Drain the brake fluid. Refer to BR-10, "
Drain and Refill" .
4. Disconnect the actuator harness from the ABS actuator and electric unit (control unit).
CAUTION:

To remove the brake tubes, use a flare nut wrench to prevent the flare nuts and brake tubes from
being damaged.

Be careful not to splash brake fluid on painted areas.
5. Disconnect the brake tubes.
6. Remove the three bolts and remove the ABS actuator and electric unit (control unit).
WFIA0241E
1. To rear left 2. To rear right 3. To front left
4. To front right 5. From the master cylinder secondary side 6. From the master cylinder primary side
7. ABS actuator and electric unit (control
unit)8. Harness connector

ACTUATOR AND ELECTRIC UNIT (ASSEMBLY)
BRC-67
[VDC/TCS/ABS]
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INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
To install, use a flare nut wrench (commercial service tool).

Always tighten brake tubes to specification when installing. Refer to BR-12, "BRAKE PIPING AND
HOSE" .

Never reuse drained brake fluid.

After installation of the ABS actuator and electric unit (control unit), refill brake system with new
brake fluid. Then bleed the air from the system. Refer to BR-11, "
Bleeding Brake System" .

After installation of ABS actuator, adjust steering angle sensor. Refer to BRC-62, "Adjustment of
Steering Angle Sensor Neutral Position" .

After installation of ABS actuator, calibrate the decel G sensor. Refer to BRC-62, "Calibration of
Decel G Sensor" .