2004 INFINITI QX56 check engine

BRAKE BOOSTER
BR-17
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Revision: August 20072004 QX56
BRAKE BOOSTERPFP:47200
On-Vehicle ServiceEFS003PJ
OPERATING CHECK
With engine stopped, change the vacuum to the atmospheric pres-
sure by depressing brake pedal several times. Then with brake
pedal fully depressed, start engine and when the vacuum pressure
reaches the standard, make sure the clearance between brake pedal
and floor panel decreases.
CAUTION:
Depressing pedal interval is approximately 5 seconds.
AIRTIGHT CHECK

Run engine at idle for approximately 1 minute, and stop it after
applying vacuum to booster. Depress brake pedal normally to
change the vacuum to the atmospheric pressure. Make sure dis-
tance between brake pedal and floor panel gradually increases.

Depress brake pedal while engine is running and stop engine
with pedal depressed. The pedal stroke should not change after
holding pedal down for 30 seconds.
CAUTION:
Depressing pedal interval is approximately 5 seconds.
BRA0037D
SBR3 65 AA

BR-18
BRAKE BOOSTER
Revision: August 20072004 QX56
Removal and InstallationEFS003PK
REMOVAL
CAUTION:

Be careful not to deform or bend brake piping while removing and installing brake booster.

Replace clevis pin if it is damaged.

Be careful not to damage brake booster stud bolt threads. If brake booster is tilted or inclined dur-
ing installation, dash panel may damage the threads.

Attach the check valve in the correct direction.
1. Remove engine room cover with power tool. Refer to EM-11, "
Removal and Installation" .
2. Remove engine air duct assembly. Refer to EM-14, "
Removal and Installation" .
3. Remove brake piping from brake master cylinder.
4. Remove brake master cylinder. Refer to BR-15, "
Removal and Installation" .
5. Remove vacuum hose from brake booster. Refer to BR-20, "
VACUUM LINES" .
6. Disconnect active boost and delta stroke sensor harness connectors from brake booster assembly.
7. Remove brake pedal attachment snap pin and clevis pin from inside the vehicle.
8. Remove nuts on brake booster and brake pedal assembly.
9. Remove brake booster assembly from dash panel.
INSPECTION AFTER REMOVAL
Output Rod Length Inspection
1. Using a handy vacuum pump, apply a vacuum of – 66.7 kPa (–
500 mmHg, –19.69 inHg) to brake booster.
2. Check output rod length.
1. Reservoir tank 2. Brake master cylinder 3. Gasket
4. Brake pedal 5. Lock nut 6. Spacer block
7. Brake booster 8. Active booster 9. Delta stroke sensor
WFIA0233E
Standard dimension when
vacuum – 66.7 kPa (– 500
mmHg, – 19.69 inHg): 15.6 − 15.9 mm
(0.614 − 0.626 in)
SBR2 08 E

BR-32
SERVICE DATA AND SPECIFICATIONS (SDS)
Revision: August 20072004 QX56
SERVICE DATA AND SPECIFICATIONS (SDS)PFP:00030
General SpecificationsEFS003PX
Unit: mm (in)
Brake PedalEFS003PY
Unit: mm (in)
Brake BoosterEFS003PZ
Unit: mm (in)
Check ValveEFS003Q0
Unit: kPa (mmHg, inHg)
Front Disc BrakeEFS003Q1
Unit: mm (in) Front brake Brake model CLZ31VC
Rotor outer diameter × thickness 320 × 26 (12.60 × 1.02)
Pad Length × width × thickness 111.0 × 73.5 × 9.5 (4.73 × 2.894 × 0.374)
Cylinder bore diameter 51 (2.01)
Rear brake Brake model AD14VE
Rotor outer diameter × thickness 320 × 14 (12.60 × 0.55)
Pad Length × width × thickness 83.0 × 33.0 × 8.5 (3.268 × 1.299 × 0.335)
Cylinder bore diameter 48 (1.89)
Control valve Valve model Electric brake force distribution
Brake booster Booster model C215T
Diaphragm diameter 215 (8.46)
Recommended brake fluidRefer to MA-10, "
RECOMMENDED FLUIDS AND LUBRI-
CANTS" .
Brake pedal height (from dash lower panel top surface) 182.3 − 192.3 (7.18 − 7.57)
Depressed pedal height [under a force of 490 N (50 kg, 110 lb)
with engine running]More than 90.3 (3.55)
Clearance between stopper rubber and the threaded end of stop
lamp switch 0.74 − 1.96 (0.029 − 0.077)
Pedal play3 − 11 (0.12 − 0.43)
Input rod installation standard dimension 15.6 − 15.9 (0.614 − 0.626)
Vacuum leakage
[at vacuum of – 66.7 (– 500, – 19.69)]Within 1.3 kPa (10 mmHg, 0.39 inHg) of vacuum for 15 seconds
Brake modelCLZ31VC
Brake padStandard thickness (new) 11.88 (0.468)
Repair limit thickness 1.0 (0.039)
Disc rotorStandard thickness (new) 26.0 (1.024)
Repair limit thickness 24.5 (0.965)
Maximum uneven wear (measured at 8 positions) 0.015 (0.0006)
Runout limit (with it attached to the vehicle) 0.04 (0.0016)

BRC-1
BRAKE CONTROL SYSTEM
F BRAKES
CONTENTS
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SECTION BRC
A
B
BRC
Revision: August 20072004 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 ............................... 40
Yaw Rate/Side/Decel G Sensor System Inspection ... 41
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 Switch System Inspection .......... 47
Active Booster System Inspection .......................... 48
Delta Stroke Sensor System Inspection ................. 49
Pressure Sensor System Inspection ...................... 51
Steering Angle Sensor Safe Mode Inspection ........ 53
CAN Communication System Inspection ................ 54
ICC System Inspection ........................................... 54
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 ........ 55
Component Inspection ............................................ 56
VDC OFF SWITCH ............................................. 56

BRC-4
[VDC/TCS/ABS]
PRECAUTIONS
Revision: August 20072004 QX56

If YES, GO TO 2.

If NO, GO TO 5.
2. Is there any indication other than indications relating to CAN communication system in the self-diagnosis
results?

If YES, GO TO 3.

If NO, GO TO 4.
3. Based on self-diagnosis results unrelated to CAN communication, carry out the inspection.
4. Malfunctions may be detected in self-diagnosis depending on control units carrying out CAN communica-
tion. Therefor, erase the self-diagnosis results.
5. Diagnose CAN communication system. Refer to BRC-10, "
CAN COMMUNICATION" .
Precautions for Brake ControlEFS003QD

During ABS operation, the brake pedal may vibrate lightly and a mechanical noise may be heard. This is
normal.

Just after starting vehicle, the brake pedal may vibrate or a motor operating noise may be heard from
engine compartment. This is a normal status of operation check.

Stopping distance may be longer than that of vehicles without ABS when vehicle drives on rough, gravel,
or snow-covered (fresh, deep snow) roads.

When an error is indicated by ABS or another warning lamp, collect all necessary information from cus-
tomer (what symptoms are present under what conditions) and check for simple causes before starting
diagnosis. Besides electrical system inspection, check booster operation, brake fluid level, and fluid leaks.

If incorrect tire sizes or types are installed on the vehicle or brake pads are not Genuine NISSAN parts,
stopping distance or steering stability may deteriorate.

If there is a radio, antenna or related wiring near control module, ABS function may have a malfunction or
error.

If aftermarket parts (car stereo, CD player, etc.) have been installed, check for incidents such as harness
pinches, open circuits or improper wiring.

If the following components are replaced with non-genuine components or modified, the VDC OFF indica-
tor lamp and SLIP indicator lamp may turn on or the VDC system may not operate properly. Components
related to suspension (shock absorbers, struts, springs, bushings, etc.), tires, wheels (exclude specified
size), components related to brake system (pads, rotors, calipers, etc.), components related to engine
(muffler, ECM, etc.), components related to body reinforcement (roll bar, tower bar, etc.).

Driving with broken or excessively worn suspension components, tires or brake system components may
cause the VDC OFF indicator lamp and the SLIP indicator lamp to turn on, and the VDC system may not
operate properly.

When the TCS or VDC is activated by sudden acceleration or sudden turn, some noise may occur. The
noise is a result of the normal operation of the TCS and VDC.

When driving on roads which have extreme slopes (such as mountainous roads) or high banks (such as
sharp curves on a freeway), the VDC may not operate normally, or the VDC warning lamp and the SLIP
indicator lamp may turn on. This is not a problem if normal operation can be resumed after restarting the
engine.

Sudden turns (such as spin turns, acceleration turns), drifting, etc. with VDC turned off may cause the yaw
rate/side G sensor to indicate a problem. This is not a problem if normal operation can be resumed after
restarting the engine.
Precautions for CAN SystemEFS003QE

Do not apply voltage of 7.0V or higher to terminal to be measured.

Maximum open terminal voltage of tester in use must be less than 7.0V.

Before checking harnesses, turn ignition switch OFF and disconnect battery negative cable.

BRC-8
[VDC/TCS/ABS]
SYSTEM DESCRIPTION
Revision: August 20072004 QX56
ABS FunctionEFS003QJ

The Anti-Lock Brake System detects wheel revolution while braking and improves handling stability during
sudden braking by electrically preventing wheel lockup. Maneuverability is also improved for avoiding
obstacles.

If the electrical system malfunctions, the Fail-Safe function is activated, the ABS becomes inoperative and
the ABS warning lamp turns on.

The electrical system can be diagnosed using CONSULT-II.

During ABS operation, the brake pedal may vibrate lightly and a mechanical noise may be heard. This is
normal.

Just after starting the vehicle, the brake pedal may vibrate or a motor operating noise may be heard from
engine compartment. This is a normal status of operation check.

Stopping distance may be longer than that of vehicles without ABS when vehicle drives on rough, gravel,
or snow-covered (fresh, deep snow) roads.
EBD FunctionEFS003QK

Electronic Brake Distribution is a function that detects subtle slippages between the front and rear wheels
during braking, and it improves handling stability by electronically controlling the brake fluid pressure
which results in reduced rear wheel slippage.

If the electrical system malfunctions, the Fail-Safe function is activated, the EBD and ABS become inoper-
ative, and the ABS warning lamp and BRAKE warning lamp are turned on.

The electrical system can be diagnosed using CONSULT-II.

During EBD operation, the brake pedal may vibrate lightly and a mechanical noise may be heard. This is
normal.

Just after starting the vehicle, the brake pedal may vibrate or a motor operating noise may be heard from
engine compartment. This is a normal status of operation check.
TCS FunctionEFS003QL

Spinning of the drive wheels is detected by the ABS actuator and electric unit (control unit) using inputs
from the wheel speed sensors. If wheel spin occurs, the drive wheel right and left brake fluid pressure
control and engine fuel cut are activated while the throttle value is restricted to reduce the engine torque
and decrease the amount of wheel spin. In addition, the throttle opening is controlled to achieve the opti-
mum engine torque.

Depending on road condition, the vehicle may have a sluggish feel. This is normal, because optimum trac-
tion has the highest priority during TCS operation.

TCS may be activated during sudden vehicle acceleration, wide open throttle acceleration, sudden trans-
mission shifts or when the vehicle is driven on a road with a varying surface friction coefficient.

The SLIP indicator lamp flashes to inform the driver of TCS operation.
VDC FunctionEFS003QM

In addition to the ABS/TCS function, the driver steering amount and brake operation amount are detected
from the steering angle sensor and front and rear pressure sensors, and the vehicle's driving status
(amount of under steering/over steering) is determined using inputs from the yaw rate sensor/side G sen-
sor, wheel speed sensors, etc. and this information is used to improve vehicle stability by controlling the
braking and engine torque application to the wheels.

The SLIP indicator lamp flashes to inform the driver of VDC operation.

During VDC operation, the vehicle body and brake pedal may vibrate lightly and a mechanical noise may
be heard. This is normal.

The ABS warning lamp, VDC OFF indicator lamp and SLIP indicator lamp may turn on when the vehicle is
subject to strong shaking or large vibration, such as when the vehicle is on a turn table or a ship while the
engine is running or on a steep slope. In this case, restart the engine on a normal road and if the ABS
warning lamp, VDC OFF indicator lamp and SLIP indicator lamp turn off, there is no problem.
Fail-Safe FunctionEFS003QN
CAUTION:
If the Fail-Safe function is activated, perform the Self Diagnosis for ABS/TCS/VDC system.

TROUBLE DIAGNOSIS
BRC-23
[VDC/TCS/ABS]
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Revision: August 20072004 QX56
Basic InspectionEFS003QU
BRAKE FLUID LEVEL, FLUID LEAK, AND BRAKE PAD INSPECTION
1. Check fluid level in the brake fluid reservoir. If fluid level is low, add fluid.
2. Check the brake piping and around the ABS actuator and electric unit (control unit) for leaks. If there is
leaking or seeping fluid, check the following items.

If ABS actuator and electric unit (control unit) connection is loose, tighten the piping to the specified
torque and recheck for leaks.

If there is damage to the connection flare nut or ABS actuator and electric unit (control unit) threads,
replace the damaged part and recheck for leaks.

When there is fluid leaking or seeping from a fluid connection, use a clean cloth to wipe off the fluid and
recheck for leaks. If fluid is still seeping out, replace the damaged part. If the fluid is leaking at the ABS
actuator and electric unit (control unit), replace the ABS actuator and electric unit (control unit) assem-
bly.
CAUTION:
The ABS actuator and electric unit (control unit) cannot be disassembled and must be replaced
as an assembly.
3. Check the brake pads for excessive wear.
POWER SYSTEM TERMINAL LOOSENESS AND BATTERY INSPECTION
Make sure the battery positive cable, negative cable and ground connection are not loose. In addition, make
sure the battery is sufficiently charged.
ABS WARNING LAMP, SLIP INDICATOR LAMP AND VDC OFF INDICATOR LAMP INSPECTION
1. Make sure ABS warning lamp, SLIP indicator lamp and VDC OFF indicator lamp (when VDC OFF switch
is off), turn on for approximately 2 seconds when the ignition switch is turned ON. If they do not, check the
VDC OFF indicator lamp and the VDC OFF switch. Refer to BRC-56, "
VDC OFF SWITCH" . Check CAN
communications. If there are no errors with the VDC OFF switch or CAN communication system, check
combination meter. Refer to DI-5, "
COMBINATION METERS" .
2. Make sure the lamps turn off approximately 2 seconds after the ignition switch is turned ON. If the lamp
does not turn off, conduct self-diagnosis.
3. With the engine running, make sure the VDC OFF indicator lamp turns on and off when the VDC OFF
switch is turned on and off. If the indicator lamp status does not correspond to switch operation, check the
VDC OFF switch. Refer to BRC-56, "
VDC OFF SWITCH" .
4. Make sure ABS warning lamp, SLIP indicator lamp and VDC OFF indicator lamp turn off approximately 2
seconds after the engine is started. If ABS warning lamp, SLIP indicator lamp or VDC OFF indicator lamp
have not turned off 10 seconds after the engine has been started, conduct self-diagnosis of the ABS actu-
ator and electric unit (control unit).
5. After conducting the self-diagnosis, be sure to erase the error memory. Refer to BRC-28, "
CONSULT-II
Function (ABS)" .

BRC-24
[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Warning Lamp and Indicator TimingEFS003QV
X: ON
—: OFF
Control Unit Input/Output Signal StandardEFS003QW
REFERENCE VALUE FROM CONSULT-II
CAUTION:
The display shows the control unit calculation data, so a normal value might be displayed even in the
event the output circuit (harness) is open or short circuited.
ConditionABS
warning lampVDC OFF
indicator lampSLIP
indicator lampRemarks
When the ignition switch is OFF — — — —
After the ignition switch is turned
ON for approx. 1 second×××—
After the ignition switch is turned
ON for approx. 2 seconds———Lamp goes off approx. 2 seconds
after the engine is started.
When the VDC OFF switch is
pressed (VDC function OFF)—×——
ABS/TCS/VDC malfunction×××—
××—When the ABS actuator and elec-
tric unit (control unit) is malfunc-
tioning (power supply or ground
malfunction).
When the VDC is malfunctioning —××—
Monitor item Display contentData monitor
Note: Error inspection
checklist
ConditionReference value in
normal operation
N POSI SIGPNP switch signal ON/
OFF conditionA/T shift position = N position ON
BRC-54, "
CAN Commu-
nication System Inspec-
tion"A/T shift position = other than
N positionsOFF
P POSI SIGPNP switch signal ON/
OFF conditionA/T shift position P position ON
BRC-54, "
CAN Commu-
nication System Inspec-
tion"A/T shift position = other than
P positionsOFF
GEAR A/T gear position1st gear 1
— 2nd gear 2
3rd gear 3
4th gear 4
5th gear 5
FR RH SENSOR
FR LH SENSOR
RR RH SENSOR
RR LH SENSORWheel speedVehicle stopped 0 [km/h (MPH)]
BRC-38, "
Wheel Sensor
System Inspection"Vehicle running (Note 1)Almost in accor-
dance with speed-
ometer display
(within ±10%)
ACCEL POS SIG Open/close condition
of throttle valve (linked
with accelerator pedal).Accelerator pedal not
depressed (ignition switch is
ON)0%
BRC-54, "
CAN Commu-
nication System Inspec-
tion"Depress accelerator pedal
(ignition switch is ON)0 to 100%
ENGINE SPEED With engine runningWith engine stopped 0 rpm
BRC-39, "
Engine System
Inspection"Engine runningAlmost in accor-
dance with
tachometer display