2010 INFINITI QX56 Ignition switch

C1140 ACTUATOR RLYBRC-55
< COMPONENT DIAGNOSIS > [VDC/TCS/ABS]
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C1140 ACTUATOR RLY
DescriptionINFOID:0000000005148013
Activates or deactivates each solenoid valve according to the signals transmitted by the ABS actuator and
electric unit (control unit).
DTC LogicINFOID:0000000005148014
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.CHECK SELF-DIAGNOSIS RESULTS
Check the self-diagnosis results.
Is above displayed on the self-diagnosis display?
YES >> Proceed to diagnosis procedure. Refer to BRC-55, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000005194932
Regarding Wiring Diagram information, refer to BRC-92, "Wiring Diagram - BRAKE CONTROL SYSTEM -".
1.CONNECTOR INSPECTION
1. Turn ignition switch OFF.
2. Disconnect ABS actuator and electric unit (control unit) connector.
3. Check terminal for deformation, disconnection, looseness, and so on. If any malfunction is found, repair or replace terminal.
4. Reconnect connectors and then perform the self-diagnosis. Refer to BRC-23, "
CONSULT-III Function
(ABS)".
Is any item indicated on the self-diagnosis display?
YES >> GO TO 2
NO >> Poor connection of connector terminal. Repair or replace connector.
2.CHECK SOLENOID, VDC SWITCH-OVER VALVE A ND ACTUATOR RELAY POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ABS actuator and electric unit (control unit) connec- tor.
3. Check voltage between ABS actuator and electric unit (control unit) connector E125 terminal 32 and ground.
Is the inspection result normal?
YES >> GO TO 3
DTC Display item Malfunction detected condition Possible cause
C1140 ACTUATOR RLY ABS actuator relay or circuit malfunction. • Harness or connector
• ABS actuator and electric unit
(control unit)
Self-diagnosis results
ACTUATOR RLY
ABS actuator and electric unit (control unit) —Volt a ge
Connector Terminal
E125 32Ground Battery voltage
AWFIA0018ZZ
Revision: April 20092010 QX56

C1142 PRESS SENSORBRC-57
< COMPONENT DIAGNOSIS > [VDC/TCS/ABS]
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C1142 PRESS SENSOR
DescriptionINFOID:0000000005148018
The front and rear pressure sensors c onvert the brake fluid pressure to an electric signal and transmit it to the
ABS actuator and electric unit (control unit).
DTC LogicINFOID:0000000005148019
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.CHECK SELF-DIAGNOSIS RESULTS
Check the self-diagnosis results.
Is above displayed on the self-diagnosis display?
YES >> Proceed to diagnosis procedure. Refer to BRC-57, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000005148020
Regarding Wiring Diagram information, refer to BRC-92, "Wiring Diagram - BRAKE CONTROL SYSTEM -".
FRONT PRESSURE SENSOR
1.CONNECTOR INSPECTION
1. Turn the ignition switch OFF.
2. Disconnect the front pressure sensor connector and AB S actuator and electric unit (control unit) connec-
tor and inspect the terminals for deformation, disconnection, looseness, or damage.
Is the inspection result normal?
YES >> GO TO 2
NO >> Repair connector.
2.FRONT PRESSURE SENSOR CIRCUIT INSPECTION
1. Measure the continuity betw een the ABS actuator and electric
unit (control unit) connector E125 (A) and front pressure sensor
connector E31 (B).
DTC Display item Malfunction detected condition Possible cause
C1142 PRESS SEN CIRCUIT Pressure sensor signal line is open or shorted, or pres-
sure sensor is malfunctioning. • Harness or connector
• Pressure sensor
• ABS actuator and electric unit
(control unit)
Self-diagnosis results
PRESS SEN CIRCUIT
ABS actuator and electric unit (control unit) Front pressure sensor
Continuity
Connector Terminal Connector Terminal
A: E125 18
B: E31 3
Ye s
19 1
20 2
AWFIA0021ZZ
Revision: April 20092010 QX56

BRC-58
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1142 PRESS SENSOR
2. Measure the continuity between the ABS actuator and electric unit (control unit) connector E125 (A) and
body ground.
Is the inspection result normal?
YES >> GO TO 3
NO >> Repair or replace harness or connector.
3.FRONT PRESSURE SENSOR INSPECTION
1. Connect the front pressure sensor and ABS act uator and electric unit (control unit) connectors.
2. Perform the front pressure sensor component inspection. Refer to BRC-59, "
Component Inspection".
Is the inspection result normal?
YES >> Inspection End.
NO >> Replace the front pressure sensor.
REAR PRESSURE SENSOR
1.CONNECTOR INSPECTION
1. Turn the ignition switch OFF.
2. Disconnect the rear pressure sensor connector and AB S actuator and electric unit (control unit) connector
and inspect the terminals for deformation, disconnection, looseness, or damage.
Is the inspection result normal?
YES >> GO TO 2
NO >> Repair connector.
2.REAR PRESSURE SENSOR CIRCUIT INSPECTION
1. Measure the continuity betw een the ABS actuator and electric
unit (control unit) connector E125 (A) and rear pressure sensor
connector E32 (B).
2. Measure the continuity between the ABS actuator and electric unit (control unit) connector E125 (A) and body ground.
Is the inspection result normal?
YES >> GO TO 3
NO >> Repair or replace harness or connector.
ABS actuator and electric unit (control unit) —Contin u it y
Connector Terminal
A: E125 18
Ground No
19
20
ABS actuator and electric unit
(control unit) Rear pressure sensor
Continuity
Connector Terminal Connector Terminal
A: E125 21
B: E32 1
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22 3
23 2
ABS actuator and electric unit (control unit) —Contin u it y
Connector Terminal
A: E125 21
Ground No
22
23
AWFIA0022ZZ
Revision: April 20092010 QX56

C1142 PRESS SENSORBRC-59
< COMPONENT DIAGNOSIS > [VDC/TCS/ABS]
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3.REAR PRESSURE SENSOR INSPECTION
1. Connect the rear pressure sens or and ABS actuator and electric unit (control unit) connectors.
2. Perform the rear pressure sensor component inspection. Refer to BRC-59, "
Component Inspection".
Is the inspection result normal?
YES >> Inspection End.
NO >> Replace the rear pressure sensor.
Component InspectionINFOID:0000000005148021
1.CHECK DATA MONITOR
On “DATA MONITOR”, select “PRESS SENSOR” or “PRESS SEN2” and check the brake fluid pressure.
Is the inspection result normal?
YES >> Inspection End
NO >> Go to diagnosis procedure. Refer to BRC-57, "
Diagnosis Procedure".
Condition PRESS SENSOR or PRESS SEN2
(DATA MONITOR)
With ignition switch turned ON and brake pedal released. Approx. 0 bar
With ignition switch turned ON and brake pedal depressed. Positive value
Revision: April 20092010 QX56

BRC-60
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1143, C1144 STEERING ANGLE SENSOR
C1143, C1144 STEERING ANGLE SENSOR
DescriptionINFOID:0000000005148023
The steering angle sensor detects the rotation amount,
angular velocity and direction of the steering wheel,
and transmits the data to the ABS actuator and el ectric unit (control unit) via CAN communication.
DTC LogicINFOID:0000000005148024
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.CHECK SELF-DIAGNOSIS RESULTS
Check the self-diagnosis results.
Is above displayed on the self-diagnosis display?
YES >> Proceed to diagnosis procedure. Refer to BRC-60, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000005148025
Regarding Wiring Diagram information, refer to BRC-92, "Wiring Diagram - BRAKE CONTROL SYSTEM -".
1.CONNECTOR INSPECTION
1. Turn ignition switch OFF.
2. Disconnect ABS actuator and electric unit (control unit) connector.
3. Disconnect steering angle sensor connector.
4. Check terminal for deformation, disconnection, looseness, and so on. If any malfunction is found, repair or replace terminal.
5. Reconnect connectors and then perform the self-diagnosis. Refer to BRC-23, "
CONSULT-III Function
(ABS)".
Is any item indicated on the self-diagnosis display?
YES >> GO TO 2
NO >> Poor connection of connector term inal. Repair or replace connector.
2.CHECK STEERING ANGLE SENSOR HARNESS
1. Turn ignition switch OFF.
2. Disconnect steering angle sensor connector.
DTC Display item Malfunction detected condition Possible cause
C1143 ST ANG SEN CIRCUIT Neutral position of steering angle sensor is dislocated, or
the steering angle sensor is malfunctioning. • Harness or connector
• Steering angle sensor
• ABS actuator and electric unit
(control unit)
C1144 ST ANG SEN SIGNAL Neutral position of steering angle sensor is not finished.
Self-diagnosis results
ST ANG SEN CIRCUIT ST ANG SEN SIGNAL
Revision: April 20092010 QX56

C1143, C1144 STEERING ANGLE SENSORBRC-61
< COMPONENT DIAGNOSIS > [VDC/TCS/ABS]
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3. Check continuity between steering angle sensor connector M17 terminal 2 and ground.
4. Turn ignition switch ON.
5. Check voltage between steering angle sensor connector M17 terminal 3 and ground.
Is the inspection result normal?
YES >> GO TO 3
NO >> Repair or replace malfunctioning components.
3.CHECK DATA MONITOR
1. Connect the steering angle sensor connector and ABS ac tuator and electric unit (control unit) connector.
2. Perform the steering angle sensor component inspection. Refer to BRC-61, "
Component Inspection".
Is the inspection result normal?
YES >> Replace ABS actuator and electric unit (control unit). Refer to BRC-116, "Removal and Installa-
tion".
NO >> Replace steering angle sensor and adjust neutra l position of steering angle sensor. Refer to BRC-
118, "Removal and Installation".
Component InspectionINFOID:0000000005148026
1.CHECK DATA MONITOR
Select “STR ANGLE SIG” in “DATA MONITOR” and check steering angle sensor signal.
Is the inspection result normal?
YES >> Inspection End
NO >> Go to diagnosis procedure. Refer to BRC-60, "
Diagnosis Procedure".
Special Repair RequirementINFOID:0000000005194918
1.ADJUSTMENT OF STEERING ANGLE SENSOR NEUTRAL POSITION
Always perform neutral position adjustment for the st eering angle sensor when replacing the ABS actuator
and electric unit (control unit). Refer to BRC-8, "
ADJUSTMENT OF STEERING ANGLE SENSOR NEUTRAL
POSITION : Description".
>> GO TO 2
Steering angle sensor —Continuity
Connector Terminal
M17 2Ground Yes
WFIA0399E
Steering angle sensor
—Voltage
Connector Terminal
M17 3Ground Battery voltage
AWFIA0023ZZ
Steering condition STR ANGLE SIG (DATA MONITOR)
Driving straight ±2.5 °
Turn 90 ° to right Approx. +90 °
Turn 90 ° to left Approx. −90 °
Revision: April 20092010 QX56

BRC-64
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1155 BRAKE FLUID LEVEL SWITCH
Is the inspection result normal?
YES >> GO TO 3
NO >> Repair or replace malfunctioning components.
3.CHECK BRAKE FLUID LEVEL SWITCH GROUND
Check continuity between brake fluid level switch connector E21 ter-
minal 2 and ground.
Is the inspection result normal?
YES >> GO TO 4
NO >> Repair or replace malfunctioning components.
4.CHECK BRAKE FLUID LEVEL SWITCH
Perform the brake fluid level switch component inspection. Refer to BRC-64, "
Component Inspection".
Is the inspection result normal?
YES >> Perform self-diagnosis again. If the same re sults appear, replace ABS actuator and electric unit
(control unit). Refer to BRC-116, "
Removal and Installation".
NO >> Replace brake fluid level switch.
Component InspectionINFOID:0000000005148031
1.CHECK BRAKE FLUID LEVEL SWITCH
1. Turn ignition switch OFF.
2. Disconnect brake fluid level switch connector.
3. Check continuity between brake fluid level switch terminals.
Is the inspection result normal?
YES >> Inspection End
NO >> Replace brake fluid level switch.
Special Repair RequirementINFOID:0000000005194919
1.ADJUSTMENT OF STEERING ANGLE SENSOR NEUTRAL POSITION
Always perform neutral position adjustment for the st eering angle sensor when replacing the ABS actuator
and electric unit (control unit). Refer to BRC-8, "
ADJUSTMENT OF STEERING ANGLE SENSOR NEUTRAL
POSITION : Description".
>> GO TO 2
2.CALIBRATION OF DECEL G SENSOR
ABS actuator and electric unit (control unit) —Continuity
Connector Terminal
E125 (A) 8Ground No
Brake fluid level switch
—Continuity
Connector Terminal
E21 2Ground Yes
AWFIA0026ZZ
Brake fluid level switch
ConditionContinuity
Te r m i n a l
1 − 2 When brake fluid is full in the reser-
voir tank.
No
When brake fluid is empty in the
reservoir tank. Ye s
ALFIA0026ZZ
Revision: April 20092010 QX56

BRC-66
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1156 ST ANG SEN COM CIR
C1156 ST ANG SEN COM CIR
DescriptionINFOID:0000000005148033
The steering angle sensor is connected to the ABS actuat
or and electric unit (control unit) in addition to CAN
lines. CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle
multiplex communication line with high data communication speed and excellent error detection ability. Many
electronic control units are equipped onto a vehicle, and each control unit shares information and links with
other control units during operation (not independent). In CAN communication, control units are connected
with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less
wiring. Each control unit transmits/receives data but selectively reads required data only.
DTC LogicINFOID:0000000005148034
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.CHECK SELF-DIAGNOSIS RESULTS
Check the self-diagnosis results.
Is above displayed on the self-diagnosis display?
YES >> Proceed to diagnosis procedure. Refer to BRC-66, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000005148035
1.CHECK CONNECTOR
1. Turn ignition switch OFF and disconnect ABS actuator and electric unit (control unit) connector, check ter-
minal for deformation, disconnection, looseness, and so on. If any malfunction is found, repair or replace
terminal.
2. Reconnect connector and perform self-diagnosis. Refer to BRC-23, "
CONSULT-III Function (ABS)".
Is above displayed on the self-diagnosis display?
YES >> Refer to LAN-14, "Trouble Diagnosis Flow Chart".
NO >> Inspection End
DTC Display item Malfunction detected condition Possible cause
C1156 ST ANG SEN COM CIR When steering angle sensor is not transmitting CAN
communication signal to th
e ABS actuator and electric
unit (control unit). • Harness or connector
• CAN communication line
• Steering angle sensor
• ABS actuator and electric unit
(control unit)
Self-diagnosis results
ST ANG SEN COM CIR
Self-diagnosis results
CAN COMM CIRCUIT
ST ANG SEN COM CIR
Revision: April 20092010 QX56