2009 INFINITI QX56 air condition

BRC-56
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1140 ACTUATOR RLY
C1140 ACTUATOR RLY
DescriptionINFOID:0000000003772551
Activates or deactivates each solenoid valve according to the signals transmitted by the ABS actuator and
electric unit (control unit).
DTC LogicINFOID:0000000003772552
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-56, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000003772553
INSPECTION PROCEDURE
1.CHECK CONNECTOR
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, re\
pair or replace terminal.
4. Reconnect connectors and then perform the self-diagnosis. Refer to BRC-24, "
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 SOLENOID, VDC SWITCH-OVER VALVE A ND ACTUATOR RELAY POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ABS actuator and elec tric unit (control unit) connec-
tor.
3. Check voltage between ABS actuator and electric unit (control unit) harness connector terminal and ground.
Is the inspection result normal?
YES >> GO TO 3
NO >> Repair or replace malfunctioning components.
3.CHECK SOLENOID, VDC SWITCH-OVER VA LVE AND ACUATOR RELAY GROUND CIRCUIT
DTCDisplay 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 g e
Connector Terminal
E125 32Ground Battery voltage
AWFIA0018ZZ
Revision: December 20092009 QX56

BRC-58
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1142 PRESS SENSOR
C1142 PRESS SENSOR
DescriptionINFOID:0000000003772556
The front and rear pressure sensors convert the brake flui
d pressure to an electric signal and transmit it to the
ABS actuator and electric unit (control unit).
DTC LogicINFOID:0000000003772557
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-58, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000003772558
FRONT PRESSURE SENSOR INSPECTION PROCEDURE
1.CONNECTOR INSPECTION
1. Turn the ignition switch OFF.
2. Disconnect the front pressure sensor connector E31 and ABS actuator and electric unit (control unit) con-
nector E125 and inspect the terminals for def ormation, 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) harness connector E125 (A) and front pres-
sure sensor harness connector E31 (B).
2. Measure the continuity between the ABS actuator and electric unit (control unit) harness connector E125
(A) and body ground.
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: December 20092009 QX56

C1142 PRESS SENSORBRC-59
< COMPONENT DIAGNOSIS > [VDC/TCS/ABS]
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Is the inspection result normal?
YES >> GO TO 3
NO >> Repair or replace harness or connector.
3.FRONT PRESSURE SENSOR INSPECTION
1. Reconnect the front pressure sensor and ABS actuator and electric unit (control unit) connectors.
2. Use “DATA MONITOR” to check if the status of “PRESS SENSOR” is normal.
Is the inspection result normal?
YES >> Inspection End.
NO >> Replace the front pressure sensor.
REAR PRESSURE SENSOR INSPECTION PROCEDURE
1.CONNECTOR INSPECTION
1. Turn the ignition switch OFF.
2. Disconnect the rear pressure sensor connector E32 and ABS actuator and electric unit (control unit) con-
nector E125 and inspect the terminals for defo rmation, 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) harness connector E125 (A) and rear pressure
sensor harness connector E32 (B).
2. Measure the continuity between t he ABS actuator and electric unit (control unit) harness connector E125
(A) and body ground.
ABS actuator and electric unit (control
unit) —Continuity
Connector Terminal
A: E125 18
Ground No
19
20
Condition PRESS SENSOR
(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
ABS actuator and electric unit (control unit) Rear pressure sensor
Continuity
Connector Terminal Connector Terminal
A: E125 21
B: E32 1
Ye s
22 3
23 2
ABS actuator and electric unit (control unit) —Con tin uit y
Connector Terminal
A: E125 21
Ground No
22
23
AWFIA0022ZZ
Revision: December 20092009 QX56

BRC-60
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1142 PRESS SENSOR
Is the inspection result normal?
YES >> GO TO 3
NO >> Repair or replace harness or connector.
3.REAR PRESSURE SENSOR INSPECTION
1. Reconnect the rear pressure sensor and ABS act uator and electric unit (control unit) connectors.
2. Use “DATA MONITOR” to check if t he status of “PRESS SEN2” is normal.
Is the inspection result normal?
YES >> Inspection End.
NO >> Replace the rear pressure sensor.
Component InspectionINFOID:0000000003772559
1.CHECK DATA MONITOR
On “DATA MONITOR”, select “PRESS SENSOR” and “PRESS SEN2” and check the brake fluid pressure.
Is the inspection result normal?
YES >> Inspection End
NO >> Go to diagnosis procedure. Refer to BRC-58, "
Diagnosis Procedure".
Special Repair RequirementINFOID:0000000003772560
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
Always perform calibration of decel G sensor when replac ing the ABS actuator and electric unit (control unit).
Refer to BRC-9, "
CALIBRATION OF DECEL G SENSOR : Description".
>> END
Condition 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
Condition PRESS SENSOR
and 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: December 20092009 QX56

C1143, C1144 STEERING ANGLE SENSORBRC-61
< COMPONENT DIAGNOSIS > [VDC/TCS/ABS]
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C1143, C1144 STEERING ANGLE SENSOR
DescriptionINFOID:0000000003772561
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:0000000003772562
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-61, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000003772563
INSPECTION PROCEDURE
1.CHECK CONNECTOR
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-24, "
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 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: December 20092009 QX56

BRC-62
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1143, C1144 STEERING ANGLE SENSOR
3. Check continuity between steering angle sensor harness con-
nector terminal and ground.
4. Turn ignition switch ON.
5. Check voltage between steering angle sensor harness connec- tor terminal 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 actuator and electric unit (control unit) connector.
2. Select “STR ANGLE SIG” in “DATA MONITOR” and check steering angle sensor signal.
Is the inspection result normal?
YES >> Replace ABS actuator and electr ic unit (control unit). Refer to BRC-116, "Removal and Installa-
tion".
NO >> Replace steering angle sensor and adjust neutral position of steering angle sensor. Refer to BRC-
118, "Removal and Installation".
Component InspectionINFOID:0000000003772564
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-61, "
Diagnosis Procedure".
Special Repair RequirementINFOID:0000000003772565
1.ADJUSTMENT OF STEERING ANGLE SENSOR NEUTRAL POSITION
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 °
Steering condition STR ANGLE SIG (DATA MONITOR)
Driving straight ±2.5 °
Turn 90 ° to right Approx. +90 °
Turn 90 ° to left Approx. −90 °
Revision: December 20092009 QX56

BRC-64
< COMPONENT DIAGNOSIS >[VDC/TCS/ABS]
C1155 BRAKE FLUID LEVEL SWITCH
C1155 BRAKE FLUID LEVEL SWITCH
DescriptionINFOID:0000000003772566
The brake fluid level switch converts the brake fluid level to an electric signal and transmits it to the ABS actu-
ator and electric unit (control unit).
DTC LogicINFOID:0000000003772567
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-64, "Diagnosis Procedure".
NO >> Inspection End
Diagnosis ProcedureINFOID:0000000003772568
INSPECTION PROCEDURE
1.CONNECTOR INSPECTION
1. Disconnect ABS actuator and electric unit (control unit) connector E125 and brake fluid level switch con- nector E21.
2. Check the terminals for deformati on, disconnection, looseness or damage.
Is the inspection result normal?
YES >> GO TO 2
NO >> Repair or replace as necessary.
2.CHECK HARNESS BETWEEN BRAKE FLUID LEVE L SWITCH AND ABS ACTUATOR AND ELECTRIC
UNIT (CONTROL UNIT)
1. Check continuity between ABS actuator and electric unit (control
unit) harness connector E125 (A) and brake fluid level switch
harness connector E21 (B).
2. Check continuity between ABS ac tuator and electric unit (control
unit) harness connector E125 (A) and ground.
Is the inspection result normal?
DTC Display item Malfunction detected condition Possible cause
C1155 BR FLUID LEVEL LOW Brake fluid level is low or communication line between
the ABS actuator and electric unit (control unit) and brake
fluid level switch is open or shorted. • Harness or connector
• Brake fluid level switch
•Brake fluid level
Self-diagnosis results
BR FLUID LEVEL LOW
ABS actuator and electric unit (control unit) Brake fluid level switch
Continuity
Connector Terminal Connector Terminal
A: E125 8B: E21 1Yes
ABS actuator and electric unit (control unit) —Continuity
Connector Terminal
A: E125 8Ground No
AWFIA0025ZZ
Revision: December 20092009 QX56

C1155 BRAKE FLUID LEVEL SWITCHBRC-65
< COMPONENT DIAGNOSIS > [VDC/TCS/ABS]
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YES >> GO TO 3
NO >> Repair or replace malfunctioning components.
3.CHECK BRAKE FLUID LEVEL SWITCH GROUND
Check continuity between brake fluid level switch harness connector
E21 and ground.
Is the inspection result normal?
YES >> GO TO 4
NO >> Repair or replace malfunctioning components.
4.CHECK BRAKE FLUID LEVEL SWITCH
Check continuity between brake fluid level switch terminals.
Is the inspection result normal?
YES >> Perform self-diagnosis again. If the same results appear, replace ABS actuator and electric unit (control unit). Refer to BRC-116, "
Removal and
Installation".
NO >> Replace brake fluid level switch.
Component InspectionINFOID:0000000003772569
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:0000000003772570
1.ADJUSTMENT OF STEERING AN GLE 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".
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
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: December 20092009 QX56