brake sensor INFINITI QX4 2005 Factory Manual PDF

SYSTEM DESCRIPTION
BRC-9
[VDC/TCS/ABS]
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ABS/EBD SYSTEM
In case of an electrical malfunction with the ABS, the ABS warning lamp, VDC OFF indicator lamp and SLIP
indicator lamp will turn on. In case of an electrical malfunction with the EBD system, the BRAKE warning lamp,
ABS warning lamp, VDC OFF indicator lamp and SLIP indicator lamp will turn on.
The system will revert to one of the following conditions of the Fail-Safe function.
1. For ABS malfunction, only the EBD is operative and the condition of the vehicle is the same condition of
vehicles without ABS/TCS/VDC system.
2. For EBD malfunction, the EBD and ABS become inoperative, and the condition of the vehicle is the same
as the condition of vehicles without ABS/TCS/VDC or EBD system.
VDC/TCS SYSTEM
In case of TCS/VDC 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 TCS/VDC system. In case of
an electrical malfunction with the TCS/VDC system, the ABS control continues to operate normally without
TCS/VDC control.
ACTIVE BOOSTER
The active brake booster consists of a vacuum booster, an active booster control group and a delta stroke
sensor. In case of brake booster system malfunction due to loss of vacuum, the delta stroke sensor will signal
the ABS actuator and electric unit (control unit) that a booster failure has occurred. The active booster then
applies supplemental force to the master cylinder relative to the amount of force exerted on the brake pedal.
Hydraulic Circuit DiagramEFS004XH
WFIA0187E

TROUBLE DIAGNOSIS
BRC-11
[VDC/TCS/ABS]
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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

TROUBLE DIAGNOSIS
BRC-25
[VDC/TCS/ABS]
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STR ANGLE SIGSteering angle
detected by steering
angle sensorStraight-ahead Approx. 0 deg
BRC-41, "Steering Angle
Sensor System"Steering wheel turned –756 to 756 deg
YAW R AT E S E NYaw rate detected by
yaw rate sensorVehicle stopped Approx. 0 d/sBRC-42, "
Yaw Rate/Side/
Decel G Sensor System
Inspection"Vehicle running –100 to 100 d/s
SIDE G SENSORTransverse G detected
by side G-sensorVehicle stopped
Approx. 0 m/s
2BRC-42, "Yaw Rate/Side/
Decel G Sensor System
Inspection"Vehicle running
–16.7 to 16.7 m/s2
BATTERY VOLTBattery voltage sup-
plied to ABS actuator
and electric unit (con-
trol unit)Ignition switch ON 10 to 16VBRC-46, "
ABS/TCS/VDC
Control Unit Power and
Ground Systems Inspec-
tion"
STOP LAMP SWStop lamp switch oper-
ationBrake pedal depressed ONBRC-45, "
Stop Lamp
Switch System Inspec-
tion"Brake pedal not depressed OFF
OFF SWVDC OFF switch
ON/OFF status VDC OFF switch ON
(When VDC OFF indicator
lamp is ON)ON
BRC-56, "
VDC OFF
SWITCH"VDC OFF switch OFF
(When VDC OFF indicator
lamp is OFF)OFF
ABS WARN LAMPABS warning lamp ON
condition (Note 2)ABS warning lamp ON ON
—
ABS warning lamp OFF OFF
MOTOR RELAYOperation status of
motor and motor relayIgnition switch ON or running
(ABS not activated)OFF
BRC-44, "
Actuator Motor,
Motor Relay, and Circuit
Inspection"Ignition switch ON or engine
running (ABS activated)ON
ACTUATOR RLYActuator relay opera-
tion statusVehicle stopped (Ignition
switch ON)OFF
BRC-44, "
Actuator Motor,
Motor Relay, and Circuit
Inspection"Vehicle stopped (Engine run-
ning)ON
OFF LAMPVDC OFF indicator
lamp status (Note 3) When VDC OFF indicator
lamp is ONON
BRC-55, "
CAN Commu-
nication System Inspec-
tion"When VDC OFF indicator
lamp is OFFOFF
SLIP LAMPSLIP indicator lamp
status (Note 4)When SLIP indicator lamp is
ONON
BRC-55, "
CAN Commu-
nication System Inspec-
tion"When SLIP indicator lamp is
OFFOFF Monitor item Display contentData monitor
Note: Error inspection
checklist
ConditionReference value in
normal operation

BRC-26
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Note 1: Confirm tire pressure is normal.
Note 2: ON/OFF timing of ABS warning lamp
ON: For approximately 1 second after ignition switch is turned ON, or when a malfunction is detected.
OFF: Approximately 1 second after ignition switch is turned ON (when system is in normal operation) and TCS/VDC function is not acti-
vated.
Note 3: ON/OFF timing of VDC OFF indicator lamp
ON: For approximately 1 second after ignition switch is turned ON, or when a malfunction is detected and VDC OFF switch is ON.
OFF: Approximately 1 second 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 1 second 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-42, "
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-30, "
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: October 20052005 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.
LATERAL G-SENSOR
[C1146]Lateral G-sensor is malfunctioning, or signal line of lateral G-sen-
sor is open or shorted.BRC-42, "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 Sensor System
Inspection"
ENGIN 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"
ENGIN 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.
ENGIN 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.
ENGIN 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.
ENGIN 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.
ACTR RELAY CIRCUIT
[C1140]ABS actuator relay or circuit malfunction.BRC-44, "
Actuator
Motor, Motor Relay, and
Circuit Inspection"
PRESS SENSE CIRCUIT
[C1142]ABS pressure sensor circuit malfunction.BRC-51, "Pressure Sen-
sor System Inspection"
ABS 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-49, "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-50, "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-49, "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.
BRC-44, "
Actuator
Motor, Motor Relay, and
Circuit Inspection"
ACC CU INTERNAL NG
[C1185]ICC control unit internal malfunction.
BRAKE BOOSTER DEFECT
[C1189]Brake booster is defective or malfunctioning. Self-diagnostic item Malfunction detecting condition Check system

TROUBLE DIAGNOSIS
BRC-35
[VDC/TCS/ABS]
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×: Applicable
–: Not applicableVDC SIGNAL
(ON/OFF)––×VDC operation (ON/OFF) status is
displayed.
EBD WARN LAMP – –×Brake warning lamp (ON/OFF) sta-
tus is displayed.
SLCT LVR POSI×××Shift position judged by PNP switch
signal.
R POSI SIG – –×Shift position judged by PNP switch
signal.
4WD FAIL REQ – –×The state of 4WD controller is dis-
played by CAN communication sig-
nal.
2WD/4WD – –×It recognizes on software whether it
is 2WD and whether it is in 4WD
state.
BST OPER SIG – –×Active booster operation (ON/OFF)
status is displayed.
PRESS SENSOR×–×Brake pressure detected by pres-
sure sensor is displayed.
CRANKING SIG – –×The input state of the key SW
START position signal is displayed.
PRESS SEN 2 – –×Brake pressure detected by pres-
sure sensor is displayed.
DELTA S SEN – –×The amount of stroke sensor move-
ments in the active booster
detected by DELTA S SEN is dis-
played.
RELEASE SW NO – –×Release switch signal (ON/OFF)
status is displayed. "ON" indicates
that the brake pedal is depressed.
"OFF" is that the brake pedal is
released.
RELEASE SW NC – –×Release switch signal (ON/OFF)
status is displayed. "OFF" indi-
cates that the brake pedal is
depressed on. "ON" is that the
brake pedal is released.
OHB FAIL – –×OHB fail status is displayed.
HBA FAIL – –×HBA fail status is displayed.
OHB SIG – –×OHB operation (ON/OFF) status is
displayed.
HBA SIG – –×HBA operation (ON/OFF) status is
displayed.
PRES CTRL ACC – –×Pressure control state (ON/OFF) is
displayed. It is applied only to an
ICC vehicle.
PRES FAIL ACC – –×Pressure control fail state (ON/
OFF) is displayed. It is applied only
to an ICC vehicle.
STP OFF RLY – –×Stop lamp relay signal (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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Revision: October 20052005 QX56
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 Sensor System InspectionEFS004Y0
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.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

BRC-48
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: October 20052005 QX56
3. CHECK THE HARNESS BETWEEN THE BRAKE FLUID LEVEL SENSOR 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 >> 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 >> Repair the circuit.ABS actuator and electric unit
(control unit) harness connector
E125Brake fluid level switch harness
connector E21Continuity
8 (P/B) 1 (P/B) Yes
8 (P/B) Ground No
Ground 2 (B) Yes

BRC-50
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: October 20052005 QX56
4. ACTIVE BOOSTER SENSOR INSPECTION
1. Reconnect the active booster and ABS actuator and electric unit (control unit) connectors.
2. Use "DATA MONITOR" to check if the status of "RELEASE SW NO" and "RELEASE SW NC" is normal.
OK or NG
OK >> Inspection End.
NG >> Replace active booster.
Delta Stroke Sensor System InspectionEFS004Y2
INSPECTION PROCEDURE
1. DISPLAY SELF DIAGNOSIS RESULTS
Check self-diagnosis result display item.
Is the above displayed in the self-diagnosis display items?
YES or NO
YES >> GO TO 2.
NO >> Inspection End.
2. CONNECTOR INSPECTION
1. Turn the ignition switch OFF.
2. Disconnect the delta stroke sensor connector E114 and ABS actuator and electric unit (control unit) con-
nector E125 and inspect the terminals for deformation, disconnection, looseness, or damage.
OK or NG
OK >> GO TO 3.
NG >> Repair connector.ConditionData monitor display
RELEASE SW NO RELEASE SW NC
When brake pedal is depressed ON OFF
When brake pedal is released OFF ON
Self-diagnosis results
DELTA S SEN NG

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
BRC-51
[VDC/TCS/ABS]
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3. DELTA STROKE SENSOR CIRCUIT INSPECTION
1. Measure the continuity between the ABS actuator and electric unit (control unit) connector E125 and delta
stroke sensor connector E114.
2. Measure the continuity between the ABS actuator and electric unit (control unit) connector E125 and body
ground.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace harness or connector.
4. DELTA STROKE SENSOR INSPECTION
1. Reconnect the delta stroke sensor and ABS actuator and electric unit (control unit) connectors.
2. Use "DATA MONITOR" to check if the status of "DELTA S SEN" is normal.
OK or NG
OK >> Inspection End.
NG >> Replace delta stroke sensor.
Pressure Sensor System InspectionEFS004Y3
FRONT PRESSURE INSPECTION PROCEDURE
1. DISPLAY SELF DIAGNOSIS RESULTS
Check self-diagnosis result display item.
Is the above displayed in the self-diagnosis display items?
YES or NO
YES >> GO TO 2.
NO >> Inspection End.ABS actuator and electric unit
(control unit) connector E125Delta stroke sensor
connector E114Continuity
26 (W/V) 1 (W/V)
Yes 39 (G/B) 3 (G/B)
40 (R/Y) 5 (R/Y)
ABS actuator and electric unit
(control unit) connector E125Body ground Continuity
26 (W/V)
—No 39 (G/B)
40 (R/Y)
ConditionData monitor display (Approx.)
DELTA S SEN
When brake pedal is released 0.00 mm (+0.6/-0.4)
When brake pedal is depressed 1.05–1.80 mm
Self-diagnosis results
PRESS SENSE CIRCUIT