2005 INFINITI QX4 relay

BRC-1
BRAKE CONTROL SYSTEM
F BRAKES
CONTENTS
C
D
E
G
H
I
J
K
L
M
SECTION BRC
A
B
BRC
Revision: October 20052005 QX56VDC/TCS/ABS
PRECAUTIONS .......................................................... 3
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 3
Precautions for Brake System .................................. 3
Precautions When Using CONSULT-II ..................... 3
CHECK POINTS FOR USING CONSULT-II ......... 3
Precautions for Brake Control .................................. 4
Precautions for CAN System ................................... 4
Wiring Diagrams and Trouble Diagnosis .................. 5
PREPARATION ........................................................... 6
Special Service Tool ................................................. 6
Commercial Service Tools ........................................ 6
SYSTEM DESCRIPTION ............................................ 7
System Components ................................................ 7
ABS Function ........................................................... 8
EBD Function ........................................................... 8
TCS Function ........................................................... 8
VDC Function ........................................................... 8
Fail-Safe Function .................................................... 8
ABS/EBD SYSTEM ............................................... 9
VDC/TCS SYSTEM ............................................... 9
ACTIVE BOOSTER ............................................... 9
Hydraulic Circuit Diagram ........................................ 9
CAN COMMUNICATION .......................................... 10
System Description ................................................ 10
TROUBLE DIAGNOSIS .............................................11
How to Perform Trouble Diagnoses for Quick and
Accurate Repair ......................................................11
INTRODUCTION ..................................................11
WORK FLOW ...................................................... 12
CLARIFY CONCERN .......................................... 13
EXAMPLE OF DIAGNOSIS SHEET ................... 13
Component Parts and Harness Connector Location ... 14
Schematic .............................................................. 15
Wiring Diagram — VDC — ..................................... 16
Basic Inspection ..................................................... 23
BRAKE FLUID LEVEL, FLUID LEAK, AND
BRAKE PAD INSPECTION ................................. 23POWER SYSTEM TERMINAL LOOSENESS
AND BATTERY INSPECTION ............................. 23
ABS WARNING LAMP, SLIP INDICATOR LAMP
AND VDC OFF INDICATOR LAMP INSPECTION ... 23
Warning Lamp and Indicator Timing ....................... 24
Control Unit Input/Output Signal Standard ............. 24
REFERENCE VALUE FROM CONSULT-II ......... 24
CONSULT-II Function (ABS) .................................. 28
CONSULT-II BASIC OPERATION PROCEDURE
... 28
SELF-DIAGNOSIS .............................................. 29
DATA MONITOR ................................................. 32
ACTIVE TEST ..................................................... 36
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC
ITEMS ........................................................................ 38
Wheel Sensor System Inspection ........................... 38
Engine System Inspection ...................................... 39
ABS/TCS/VDC Control Unit Inspection .................. 40
Steering Angle Sensor System ............................... 41
Yaw Rate/Side/Decel G Sensor System Inspection ... 42
Solenoid and VDC Change-Over Valve System
Inspection ............................................................... 43
Actuator Motor, Motor Relay, and Circuit Inspection ... 44
Stop Lamp Switch System Inspection .................... 45
ABS/TCS/VDC Control Unit Power and Ground
Systems Inspection ................................................ 46
Brake Fluid Level Sensor System Inspection ......... 47
Active Booster System Inspection .......................... 49
Delta Stroke Sensor System Inspection ................. 50
Pressure Sensor System Inspection ...................... 51
Steering Angle Sensor Safe Mode Inspection ........ 54
CAN Communication System Inspection ................ 55
Inspection For Self-diagnosis Result "ST ANGLE
SEN SIGNAL" ......................................................... 55
Inspection For Self-diagnosis Result "DECEL G
SEN SET" ............................................................... 55
VDC OFF Indicator lamp Does Not Illuminate ........ 56
Component Inspection ............................................ 56
VDC OFF SWITCH ............................................. 56

TROUBLE DIAGNOSIS
BRC-25
[VDC/TCS/ABS]
C
D
E
G
H
I
J
K
L
MA
B
BRC
Revision: October 20052005 QX56
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

TROUBLE DIAGNOSIS
BRC-31
[VDC/TCS/ABS]
C
D
E
G
H
I
J
K
L
MA
B
BRC
Revision: October 20052005 QX56
FR LH IN ABS SOL
[C1120]Circuit of front LH IN ABS solenoid is open or shorted, or control
line is open or shorted to power supply or ground.
BRC-43, "
Solenoid and
VDC Change-Over Valve
System Inspection"
FR LH OUT ABS SOL
[C1121]Circuit of front LH OUT ABS solenoid is open or shorted, or con-
trol line is open or shorted to power supply or ground.
RR RH IN ABS SOL
[C1126]Circuit of rear RH IN ABS solenoid is open or shorted, or control
line is open or shorted to power supply or ground.
RR RH OUT ABS SOL
[C1127]Circuit of rear RH OUT ABS solenoid is open or shorted, or con-
trol line is open or shorted to power supply or ground.
FR RH IN ABS SOL
[C1122]Circuit of front RH IN ABS solenoid is open or shorted, or control
line is open or shorted to power supply or ground.
FR RH OUT ABS SOL
[C1123]Circuit of front RH OUT ABS solenoid is open or shorted, or con-
trol line is open or shorted to power supply or ground.
RR LH IN ABS SOL
[C1124]Circuit of rear LH IN ABS solenoid is open or shorted, or control
line is open or shorted to power supply or ground.
RR LH OUT ABS SOL
[C1125] Circuit of rear LH OUT ABS solenoid is open or shorted, or con-
trol line is open or shorted to power supply or ground.
CV1
[C1164]Front side VDC switch-over solenoid valve (cut valve) is open or
shorted, or control line is open or shorted to power supply or
ground.
CV2
[C1165]Rear side VDC switch-over solenoid valve (cut valve) is open or
shorted, or control line is open or shorted to power supply or
ground.
SV1
[C1166]Front side VDC switch-over solenoid valve (suction valve) is
open or shorted, or control line is open or shorted to power sup-
ply or ground.
SV2
[C1167]Rear side VDC switch-over solenoid valve (suction valve) is open
or shorted, or control line is open or shorted to power supply or
ground.
PUMP MOTOR (Note 3)
[ C 1111 ]During actuator motor operation with ON, when actuator motor
turns OFF or when control line for actuator motor relay is open.BRC-44, "
Actuator
Motor, Motor Relay, and
Circuit Inspection"During actuator motor operation with OFF, when actuator motor
turns ON or when control line for relay is shorted to ground.
BATTERY VOLTAGE
[ABNORMAL]
[C1109]ABS actuator and electric unit (control unit) power voltage is too
low.BRC-46, "
ABS/TCS/
VDC Control Unit Power
and Ground Systems
Inspection"
ST ANGLE SEN SIGNAL
[C1144]Neutral position correction of steering angle sensor is not fin-
ished.BRC-55, "
Inspection For
Self-diagnosis Result
"ST ANGLE SEN SIG-
NAL""
ST ANG SEN COM CIR
[C1156]CAN communication line or steering angle sensor has generated
an error.BRC-41, "Steering Angle
Sensor System"
LONGITUDINAL G-SENSOR
[ C 111 3 ]Longitudinal G-sensor is malfunctioning, or signal line of longitu-
dinal G-sensor is open or shorted.BRC-42, "Yaw Rate/
Side/Decel G Sensor
System Inspection"
CONTROLLER FAILURE
[ C 111 0 ]Internal malfunction of ABS actuator and electric unit (control
unit)BRC-40, "ABS/TCS/
VDC Control Unit
Inspection"
CAN COMM CIRCUIT
[U1000]

CAN communication line is open or shorted.

ABS actuator and electric unit (control unit) internal malfunc-
tion

Battery voltage for ECM is suddenly interrupted for approxi-
mately 0.5 second or more.BRC-55, "
CAN Commu-
nication System Inspec-
tion" (Note 2) Self-diagnostic item Malfunction detecting condition Check system

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

BRC-34
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: October 20052005 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
BRC-35
[VDC/TCS/ABS]
C
D
E
G
H
I
J
K
L
MA
B
BRC
Revision: October 20052005 QX56
×: 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
BRC-37
[VDC/TCS/ABS]
C
D
E
G
H
I
J
K
L
MA
B
BRC
Revision: October 20052005 QX56
ABS Motor
Touch “ON” and “OFF” on the screen. Check that ABS motor relay
operates as shown in table below.
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.
Operation ON OFF
ABS actuator relay ON ON
ABS motor relay ON OFF
SFIA0593E