2009 INFINITI QX56 engine

BR-24
< ON-VEHICLE REPAIR >
BRAKE TUBE AND HOSE
1. Check brake lines (tubes and hoses), and connections for fluid leaks, damage, twist, deformation, contact
with other parts, and loose connections. Replace any parts as necessary. Refer to BR-13, "
Hydraulic Cir-
cuit".
2. While depressing brake pedal under a force of 785 N (80 kg-f, 177 lb-f) with engine running for approxi- mately 5 seconds, check each part for fluid leaks.
Revision: December 20092009 QX56

BR-28
< ON-VEHICLE REPAIR >
VACUUM LINES
VACUUM LINES
Removal and InstallationINFOID:0000000003772441
REMOVAL
1. Remove engine room cover.
2. Disconnect vacuum hose from hose clip.
3. Release clamps and disconnect vacuum hose.
4. Remove check valve from brake booster.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
• Insert vacuum hose for at least 24 mm (0.94 in).
• Do not use lubricating oil during assembly.
1. Hose clip2. Clamp3. Vacuum hose
4. Check valve
LFIA0216E
SBR225B
Revision: December 20092009 QX56

FRONT DISC BRAKEBR-31
< ON-VEHICLE REPAIR >
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Exploded View of Brake CaliperINFOID:0000000005856030
Removal and Installation of Brake Caliper and RotorINFOID:0000000005856031
WARNING:
Clean dust on caliper and brake pad with a vacuum dust collector to minimize the hazard of air borne
particles or other materials.
CAUTION:
• While removing cylinder bod y, do not depress brake pedal because piston will pop out.
• It is not necessary to remove bolts on torque member and brake hose except for disassembly or
replacement of caliper assembly. In this case, hang cylinder body with a wire so as not to stretch
brake hose.
• Do not damage piston boot.
• If any shim is subject to serious corrosion, replace it with a new one.
• Always replace shim and shim cover as a set when replacing brake pads.
• Keep rotor free from brake fluid.
• Burnish the brake pads and disc rotor mutually contacting surfaces, after refinishing or replacing rotors, after replacing pads, or if a so ft pedal occurs at very low mileage.
REMOVAL
1. Remove front wheel and tires using power tool.
2. Fasten disc rotor using wheel nut.
3. Drain brake fluid. Refer to CO-11, "
Changing Engine Coolant".
4. Remove union bolt, and then disconnect brake hose from caliper assembly.
1. Sliding pin bolt 2. Bleed valve 3. Cap
4. Union bolt 5. Brake hose 6. Copper washer
7. Torque member bolt 8. Sliding pin boot 9. Torque member
10. Sliding pin 11. Piston boot 12. Piston
13. Piston seal 14. Cylinder body B: Brake fluid
R: Rubber grease
AWFIA0683GB
Revision: December 20092009 QX56

INSPECTION AND ADJUSTMENTBRC-9
< BASIC INSPECTION > [VDC/TCS/ABS]
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>> GO TO 2
2.PERFORM THE NEUTRAL POSITION ADJUST MENT FOR THE STEERING ANGLE SENSOR
1. On the CONSULT-III screen, touch “WORK SUPP ORT” and “ST ANG SEN ADJUSTMENT” in order.
2. Touch “START”. CAUTION:
Do not touch steering wheel whil e adjusting steering angle sensor.
3. After approximately 10 seconds, touch “END”. NOTE:
After approximately 60 seconds, it ends automatically.
4. Turn ignition switch OFF, then turn it ON again. CAUTION:
Be sure to perform above operation.
>> GO TO 3
3.CHECK DATA MONITOR
1. Run vehicle with front wheels in straight-ahead position, then stop.
2. Select “DATA MONITOR”. Then make sure “STR ANGLE SIG” is within 0 ±2.5 °.
Is the steering angle within the specified range?
YES >> GO TO 4
NO >> Perform the neutral position adjustment fo r the steering angle sensor again, GO TO 1
4.ERASE THE SELF-DIAGNOSIS MEMORY
Erase the self-diagnosis memory of the ABS ac tuator and electric unit (control unit) and ECM.
• ABS actuator and electric unit (control unit): Refer to BRC-24, "
CONSULT-III Function (ABS)".
• ECM: Refer to EC-63, "
CONSULT-III Function (ENGINE)".
Are the memories erased?
YES >> Inspection End
NO >> Check the items indica ted by the self-diagnosis.
CALIBRATION OF DECEL G SENSOR
CALIBRATION OF DECEL G SENSOR : DescriptionINFOID:0000000003772482
Refer to the table below to determine if calibration of the decel G sensor is required.
×: Required –: Not required
CALIBRATION OF DECEL G SENSOR : Special Repair RequirementINFOID:0000000003772483
CALIBRATION OF DECEL G SENSOR
CAUTION:
To calibrate the decel G sensor, make sure to use CONSULT-III
Situation Calibration of decel G sensor
Removing/Insta lling ABS actuator and electr ic unit (control unit) —
Replacing ABS actuator and elec tric unit (control unit) ×
Removing/Installing steering angle sensor ×
Replacing steering angle sensor ×
Removing/Installing steering components ×
Replacing steering components ×
Removing/Installing suspension components ×
Replacing suspension components ×
Change tires to new ones —
Tire rotation —
Adjusting wheel alignment ×
Revision: December 20092009 QX56

BRC-10
< BASIC INSPECTION >[VDC/TCS/ABS]
INSPECTION AND ADJUSTMENT
(Calibration cannot be
done without CONSULT-III)
1.ALIGN THE VEHICLE STATUS
Stop vehicle with front wheels in straight-ahead position.
>> GO TO 2
2.PERFORM CALIBRATION OF DECEL G SENSOR
1. On the CONSULT-III screen, touch “WORK SUPPORT” and “DECEL G SEN CALIBRATION” in order.
2. Touch “START”.
3. After approximately 10 seconds, touch “END”. NOTE:
After approximately 60 seconds, it ends automatically.
4. Turn ignition switch OFF, then turn it ON again.
CAUTION:
Be sure to perform above operation.
>> GO TO 3
3.CHECK DATA MONITOR
1. Run vehicle with front wheels in straight-ahead position, then stop.
2. Select “DATA MONITOR”. Then make sure “DECEL G SEN” is within ± 0.08G.
Is the inspection result normal?
YES >> GO TO 4
NO >> Perform calibration of decel G sensor again, GO TO 1
4.ERASE THE SELF-DIAGNOSIS MEMORY
Erase the self-diagnosis memory of the ABS ac tuator and electric unit (control unit) and ECM.
• ABS actuator and electric unit (control unit): Refer to BRC-24, "
CONSULT-III Function (ABS)".
• ECM: Refer to EC-63, "
CONSULT-III Function (ENGINE)".
Are the memories erased?
YES >> Inspection End
NO >> Check the items indicated by the self-diagnosis.
Revision: December 20092009 QX56

BRC-12
< FUNCTION DIAGNOSIS >[VDC/TCS/ABS]
VDC
Hydraulic Circuit Diagram
INFOID:0000000005874974
System DescriptionINFOID:0000000003772485
• Vehicle Dynamics Control system detects driver ′s steering operation amount and brake pedal travel from
steering angle sensor and pressure sensors. Using information from yaw rate/side/decel G sensor and
wheel sensor, VDC judges driving condition (conditions of under steer and over steer) to improve vehicle
driving stability by controlling brake application to 4 wheels and engine output.
• During VDC operation, it inform s driver of system operation by flashing SLIP indicator lamp.
• Electrical system diagnosis by CONSULT-III is available.
WFIA0187E
Revision: December 20092009 QX56

TCS
BRC-15
< FUNCTION DIAGNOSIS > [VDC/TCS/ABS]
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TCS
System DiagramINFOID:0000000003772488
System DescriptionINFOID:0000000003772489
• Traction Control System is a function that electronically controls engine torque, brake fluid pressure and A/T gear position to ensure the optimum slippage ratio at drive wheels by computing wheel speed signals from 4
wheel sensors. When ABS actuator and electric unit (control unit) detects a spin at drive wheels (rear
wheels), it compares wheel speed signals from all 4 wheel s. At this time, LH and RH rear brake fluid pres-
sure are controlled, while fuel being cut to engine and throttle valve being closed to reduce engine torque by
the control unit. Further more, throttle position is continuously controlled to ensure the optimum engine
torque at all times.
• During TCS operation, it inform s driver of system operation by flashing SLIP indicator lamp.
• Electrical system diagnosis by CONSULT-III is available.
AWFIA0065GB
Revision: December 20092009 QX56

BRC-24
< FUNCTION DIAGNOSIS >[VDC/TCS/ABS]
DIAGNOSIS SYSTEM [
ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)]
DIAGNOSIS SYSTEM [ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)]
CONSULT-III Function (ABS)INFOID:0000000003772500
FUNCTION
CONSULT-III can display each diagnostic item us ing the diagnostic test modes shown following.
SELF-DIAG RESULTS MODE
Operation Procedure
1. Before performing the self-diagnosis, start engine and drive vehicle at 30 km/h (19 MPH) or more for
approximately 1 minute.
How to Erase Self-d iagnosis Results
1. After erasing DTC memory, start engine and drive vehicle at 30 km/h (19 MPH) or more for approximately
1 minute as the final inspection, and make sure that the ABS warning lamp, VDC OFF indicator lamp,
SLIP indicator lamp and brake warning lamp turn OFF.
CAUTION:
If memory cannot be erased, pe rform applicable diagnosis.
NOTE:
• When the wheel sensor malfunctions, after inspecting the wheel sensor system, the ABS warning lamp,
VDC OFF indicator lamp, SLIP indicator lamp and brake warning lamp will not turn OFF even when the
system is normal unless the vehicle is driving at approximately 30 km/h (19 MPH) or more for approxi-
mately 1 minute.
• Brake warning lamp will turn ON in case of parking brake operation (when switch is ON) or of brake fluid level switch operation (when brake fluid is insufficient).
• VDC OFF switch should not stay “ON” position.
Display Item List
Refer to BRC-100, "DTC No. Index".
DATA MONITOR MODE
Display Item List
Diagnostic test mode Function
Work support This mode enables a technician to adjust some devices faster and more accurately by following
the indications on CONSULT-III.
Self-diagnostic results Self-diagnostic results can be read and erased quickly.
Data monitor Input/Output data in the ABS actuator and electric unit (control unit) can be read.
Active test Diagnostic test mode is which CONSULT-III drives some actuators apart from the ABS actuator
and electric unit (control unit) and also shifts some parameters in a specified range.
ECU part number ABS actuator and electric unit (control unit) part number can be read.
CAN diagnostic support monitor The results of transmit/receive diagnosis of CAN communication can be read.
Item
(Unit) Data monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELECTION
FROM MENU
GEAR
(1, 2, 3, 4, R) ××× Gear position judged by transmis-
sion range switch signal is dis-
played.
FR RH SENSOR
(km/h, MPH) ××× Wheel speed calculated by front RH
wheel sensor signal is displayed.
FR LH SENSOR
(km/h, MPH) ××× Wheel speed calculated by front LH
wheel sensor signal is displayed.
RR RH SENSOR
(km/h, MPH) ×××
Wheel speed calculated by rear RH
wheel sensor signal is displayed.
Revision: December 20092009 QX56