2004 INFINITI QX56 Air

TROUBLE DIAGNOSES FOR SYMPTOMS
BRC-57
[VDC/TCS/ABS]
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TROUBLE DIAGNOSES FOR SYMPTOMSPFP:99999
ABS Works FrequentlyEFS0044T
1. CHECK WARNING LAMP ACTIVATION
Make sure warning lamp remains off while driving.
OK or NG
OK >> GO TO 2.
NG >> Carry out self-diagnosis. Refer to BRC-29, "
SELF-DIAGNOSIS" .
2. CHECK WHEEL SENSORS
Check the following.

Wheel sensor mounting for looseness

Wheel sensors for physical damage

Wheel sensor connectors for terminal damage or loose connections
OK or NG
OK >> GO TO 3.
NG >> Repair or replace as necessary.
3. CHECK FRONT AND REAR AXLES
Check front and rear axles for excessive looseness. Refer to FAX-5, "
WHEEL HUB" or RAX-5, "WHEEL
HUB" .
OK or NG
OK >> GO TO 4.
NG >> Repair as necessary.
4. CHECK BRAKE FLUID PRESSURE
Check brake fluid pressure distribution.
Refer to BRC-23, "
Basic Inspection" .
Is brake fluid pressure distribution normal?
YES >> Inspection End.
NO >> Perform Basic Inspection. Refer to BRC-23, "
Basic Inspection" .

BRC-58
[VDC/TCS/ABS]
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: August 20072004 QX56
Unexpected Pedal ActionEFS0044U
1. CHECK WARNING LAMP ACTIVATION
Make sure warning lamp remains off while driving.
OK or NG
OK >> GO TO 2.
NG >> Carry out self-diagnosis. Refer to BRC-29, "
SELF-DIAGNOSIS" .
2. CHECK BRAKE PEDAL STROKE
Check brake pedal stroke.
Is pedal stroke excessive?
YES >> Perform Basic Inspection. Refer to BRC-23, "Basic
Inspection" .
NO >> GO TO 3.
3. CHECK CONNECTOR AND BRAKING PERFORMANCE
1. Disable ABS by disconnecting ABS actuator and electric unit (control unit) connector.
2. Drive vehicle and check brake operation.
NOTE:
Stopping distance may be longer than vehicles without ABS when road condition is slippery.
NOTE:
Driving the vehicle with the ABS actuator and electric unit (control unit) disconnected may induce DTCs in
electrical control units using CAN communication. After the inspection, clear all DTCs. Refer to BRC-10,
"CAN COMMUNICATION" .
OK or NG
OK >> GO TO 4.
NG >> Perform Basic Inspection. Refer to BRC-23, "
Basic Inspection" .
4. CHECK WHEEL SENSORS
Check the following.

Wheel sensor mounting for looseness

Wheel sensors for physical damage

Wheel sensor connectors for terminal damage or loose connections
OK or NG
OK >> Check ABS actuator and electric unit (control unit) connector terminals for deformation, discon-
nection, looseness or damage. Reconnect ABS actuator and electric unit (control unit) harness
connector. Then retest.
NG >> Repair or replace as necessary.
SBR5 40 A

BRC-60
[VDC/TCS/ABS]
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: August 20072004 QX56
ABS Warning Lamp Does Not Come On When Ignition Switch Is Turned OnEFS0044Y
1. CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT) FUSES
Check 30A fusible link h and 40A fusible link i for ABS actuator and electric unit (control unit). For fusible
link layout, refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .
OK or NG
OK >> GO TO 2.
NG >> If fusible link is blown, be sure to eliminate cause of problem before replacing.
2. CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT) POWER SUPPLY CIRCUITS
1. Disconnect ABS actuator and electric unit (control unit) connec-
tor.
2. Check voltage between ABS actuator and electric unit (control
unit) connector terminal 1 (Y) and ground and terminal 32 (B/Y)
and ground.
Does battery voltage exist?
YES >> GO TO 3.
NO >> Repair harness or connectors between fusible link and
ABS actuator and electric unit (control unit).
3. CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT) GROUND CIRCUIT
Check continuity between ABS actuator and electric unit (control
unit) connector terminal 16 (B) and ground and terminal 47 (B) and
ground.
Does continuity exist?
YES >> Replace ABS actuator and electric unit (control unit).
Refer to BRC-66, "
Removal and Installation" .
NO >> Repair harness or connectors between ABS actuator
and electric unit (control unit) and ground.
ABS Warning Lamp Stays On When Ignition Switch Is Turned OnEFS0044Z
1. CARRY OUT SELF-DIAGNOSIS
Carry out self-diagnosis. Refer to BRC-29, "
SELF-DIAGNOSIS" .
Are malfunctions detected in self-diagnosis?
YES >> Refer to BRC-30, "Display Item List" .
NO >> Refer to DI-31, "
WARNING LAMPS" .
WFIA0199E
WFIA0196E

TROUBLE DIAGNOSES FOR SYMPTOMS
BRC-61
[VDC/TCS/ABS]
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Revision: August 20072004 QX56
Vehicle Jerks During TCS/VDC ActivationEFS00450
1. ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT) SELF-DIAGNOSIS
Perform ABS actuator and electric unit (control unit) self-diagnosis.
Are self-diagnosis result items displayed?
YES >> After checking and repairing the applicable item, perform the ABS actuator and electric unit (con-
trol unit) self-diagnosis again.
NO >> GO TO 2.
2. ENGINE SPEED SIGNAL INSPECTION
Perform data monitor with CONSULT-II for the ABS actuator and electric unit (control unit).
Is the engine speed at idle 400 rpm or higher?
YES >> GO TO 4.
NO >> GO TO 3.
3. ECM SELF-DIAGNOSIS
Perform ECM self-diagnosis.
Are self-diagnosis result items displayed?
YES >> After checking and repairing the applicable item, perform the ECM self-diagnosis again.
NO >> GO TO 4.
4. TCM SELF-DIAGNOSIS
Perform TCM self-diagnosis.
Are self-diagnosis result items displayed?
YES >> After checking and repairing the applicable item, perform the TCM self-diagnosis again.
NO >> GO TO 5.
5. CONNECTOR INSPECTION
Disconnect the ABS actuator and electric unit (control unit) connector and the ECM connectors and check the
terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace as necessary.
6. CAN COMMUNICATION INSPECTION
Check the CAN communication system. Refer to BRC-54, "
CAN Communication System Inspection" .
OK or NG
OK >> Inspection End.
NG >> Refer to LAN-5, "
CAN COMMUNICATION" .

ACTUATOR AND ELECTRIC UNIT (ASSEMBLY)
BRC-67
[VDC/TCS/ABS]
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Revision: August 20072004 QX56
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
To install, use a flare nut wrench (commercial service tool).

Always tighten brake tubes to specification when installing. Refer to BR-12, "BRAKE PIPING AND
HOSE" .

Never reuse drained brake fluid.

After installation of the ABS actuator and electric unit (control unit), refill brake system with new
brake fluid. Then bleed the air from the system. Refer to BR-11, "
Bleeding Brake System" .

After installation of ABS actuator, adjust steering angle sensor. Refer to BRC-62, "Adjustment of
Steering Angle Sensor Neutral Position" .

After installation of ABS actuator, calibrate the decel G sensor. Refer to BRC-62, "Calibration of
Decel G Sensor" .

CO-1
ENGINE COOLING SYSTEM
B ENGINE
CONTENTS
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SECTION CO
A
CO
Revision: August 20072004 QX56 PRECAUTIONS .......................................................... 2
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 2
PREPARATION ........................................................... 3
Special Service Tools ............................................... 3
Commercial Service Tools ........................................ 3
OVERHEATING CAUSE ANALYSIS .......................... 4
Troubleshooting Chart .............................................. 4
COOLING SYSTEM .................................................... 6
Cooling Circuit .......................................................... 6
System Drawing ....................................................... 7
ENGINE COOLANT .................................................... 8
Inspection ................................................................. 8
LEVEL CHECK ..................................................... 8
CHECKING COOLING SYSTEM FOR LEAKS ..... 8
CHECKING RESERVOIR CAP ............................. 8
CHECKING RADIATOR CAP ................................ 8
Changing Engine Coolant ........................................ 8
DRAINING ENGINE COOLANT ........................... 8
REFILLING ENGINE COOLANT .......................... 9
FLUSHING COOLING SYSTEM ........................... 9
RADIATOR ................................................................ 10
Removal and Installation ........................................ 10
REMOVAL ........................................................... 10
INSTALLATION ................................................... 12
INSPECTION AFTER INSTALLATION ............... 12
Checking Radiator .................................................. 12ENGINE COOLING FAN ........................................... 13
Removal and Installation (Crankshaft Driven Type) ... 13
REMOVAL ........................................................... 13
INSPECTION AFTER REMOVAL ....................... 13
INSTALLATION ................................................... 13
INSPECTION AFTER INSTALLATION ................ 13
Removal and Installation (Motor Driven Type) ....... 14
REMOVAL ........................................................... 14
INSTALLATION ................................................... 14
WATER PUMP .......................................................... 15
Removal and Installation ........................................ 15
REMOVAL ........................................................... 15
INSPECTION AFTER REMOVAL ....................... 15
INSTALLATION ................................................... 15
INSPECTION AFTER INSTALLATION ................ 16
THERMOSTAT AND WATER PIPING ...................... 17
Removal and Installation ........................................ 17
REMOVAL ........................................................... 17
INSPECTION AFTER REMOVAL ....................... 18
INSTALLATION ................................................... 18
INSPECTION AFTER INSTALLATION ................ 18
SERVICE DATA AND SPECIFICATIONS (SDS) ...... 19
Standard and Limit .................................................. 19
ENGINE COOLANT CAPACITY (APPROXI-
MATE) .................................................................. 19
THERMOSTAT .................................................... 19
RADIATOR .......................................................... 19

CO-2Revision: August 2007
PRECAUTIONS
2004 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EBS00I4Q
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WAR NIN G:

To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.

CO-4Revision: August 2007
OVERHEATING CAUSE ANALYSIS
2004 QX56
OVERHEATING CAUSE ANALYSISPFP:00012
Troubleshooting ChartEBS00I4T
Symptom Check items
Cooling sys-
tem parts
malfunctionPoor heat transferWater pump malfunction Worn or loose drive belt
— Thermostat stuck closed —
Damaged finsDust contamination or
paper clogging
Physical damage
Clogged radiator cooling
tubeExcess foreign material
(rust, dirt, sand, etc.)
Water cut valve malfunctionExcess foreign material
(rust, dirt, sand, etc.), phys-
ical damage
Reduced air flowCooling fan does not oper-
ate
Fan assembly — High resistance to fan rota-
tion
Damaged fan blades
Damaged radiator shroud — — —
Improper engine coolant
mixture ratio—— —
Poor engine coolant quality — Engine coolant density —
Insufficient engine coolantEngine coolant leaksCooling hoseLoose clamp
Cracked hose
Water pump Poor sealing
Radiator capLoose
Poor sealing
RadiatorO-ring for damage, deterio-
ration or improper fitting
Cracked radiator tank
Cracked radiator core
Reservoir tank Cracked reservoir tank
Overflowing reservoir tankExhaust gas leaks into
cooling systemCylinder head deterioration
Cylinder head gasket dete-
rioration