INFINITI QX56 2007 Factory Service Manual

PRECAUTIONS
BRC-3
< SERVICE INFORMATION >[VDC/TCS/ABS]
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SERVICE INFORMATION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000003532761
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.
WARNING:
• 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 performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal
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 har-
ness connectors.
Precaution for Brake SystemINFOID:0000000003532762
CAUTION:
• Refer to MA-10
for recommended brake fluid.
• Never reuse drained brake fluid.
• Be careful not to splash brake fluid on painted areas; it may cause paint damage. If brake fluid is
splashed on painted areas, wash it away with water immediately.
• To clean or wash all parts of master cylinder and disc brake caliper, use clean brake fluid.
• Never use mineral oils such as gasoline or kerosene. They will ruin rubber parts of the hydraulic sys-
tem.
• Use flare nut wrench when removing and installing brake
tube.
• If a brake fluid leak is found, the part must be disassembled
without fail. Then it has to be replaced with a new one if a
defect exists.
• Turn the ignition switch OFF and remove the connector of the
ABS actuator and electric unit (control unit) or the battery ter-
minal before performing the work.
• Always torque brake lines when installing.
• Burnish the brake contact surfaces after refinishing or replac-
ing rotors, after replacing pads, or if a soft pedal occurs at
very low mileage.
Refer to BR-20, "
Disassembly and Assembly of Brake Caliper" (front disc brake) or BR-26, "Brake
Caliper" (rear disc brake).
WARNING:
• Clean brake pads and shoes with a waste cloth, then wipe with a dust collector.
Precaution When Using CONSULT-IIINFOID:0000000003532763
When connecting CONSULT-II to data link connector, connect them through CONSULT-II CONVERTER.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
CHECK POINTS FOR USING CONSULT-II
1. Has CONSULT-II been used without connecting CONSULT-II CONVERTER on this vehicle?
SBR686C

BRC-4
< SERVICE INFORMATION >[VDC/TCS/ABS]
PRECAUTIONS
• 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 LAN-7
.
Precaution for Brake ControlINFOID:0000000003532764
• 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 customer
(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, stop-
ping 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 indicator
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 (muf-
fler, 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 indi-
cator 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/decel G sensor to indicate a problem. This is not a problem if normal operation can be resumed
after restarting the engine.
Precaution for CAN SystemINFOID:0000000003532765
• 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.

PRECAUTIONS
BRC-5
< SERVICE INFORMATION >[VDC/TCS/ABS]
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• Area to be repaired must be soldered and wrapped with tape.
Make sure that fraying of twisted wire is within 110 mm (4.33 in).
• Do not make a bypass connection to repaired area. (If the circuit is
bypassed, characteristics of twisted wire will be lost.)
PKIA0306E
PKIA0307E

BRC-6
< SERVICE INFORMATION >[VDC/TCS/ABS]
PREPARATION
PREPARATION
Special Service ToolINFOID:0000000003532766
The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.
Commercial Service ToolINFOID:0000000003532767
Tool number
(Kent-Moore No.)
Tool nameDescription
—
(J-45741)
ABS active wheel sensor testerChecking operation of ABS active wheel sen-
sors
WFIA0101E
Tool nameDescription
1. Flare nut crowfoot
2. Torque wrenchRemoving and installing brake piping
a: 10mm (0.39 in)/12mm (0.47 in)
S-NT360

SYSTEM DESCRIPTION
BRC-7
< SERVICE INFORMATION >[VDC/TCS/ABS]
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SYSTEM DESCRIPTION
System ComponentINFOID:0000000003532768
WFIA0222E

BRC-8
< SERVICE INFORMATION >[VDC/TCS/ABS]
SYSTEM DESCRIPTION
ABS Function
INFOID:0000000003532769
• 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 obsta-
cles.
• 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 FunctionINFOID:0000000003532770
• 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 inopera-
tive, 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 FunctionINFOID:0000000003532771
• 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 optimum 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 transmis-
sion 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 FunctionINFOID:0000000003532772
• 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 sensor, 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 warn-
ing lamp, VDC OFF indicator lamp and SLIP indicator lamp turn off, there is no problem.
Fail-Safe FunctionINFOID:0000000003532773
CAUTION:
If the Fail-Safe function is activated, perform the Self Diagnosis for ABS/TCS/VDC system.
ABS/EBD SYSTEM

SYSTEM DESCRIPTION
BRC-9
< SERVICE INFORMATION >[VDC/TCS/ABS]
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In case of an electrical malfunction with the ABS, the ABS warning lamp, VDC OFF indicator lamp and SLIP
indicator lamp will turn on. In case of an electrical malfunction with the EBD system, the BRAKE warning lamp,
ABS warning lamp, VDC OFF indicator lamp and SLIP indicator lamp will turn on.
The system will revert to one of the following conditions of the Fail-Safe function.
1. For ABS malfunction, only the EBD is operative and the condition of the vehicle is the same condition of
vehicles without ABS/TCS/VDC system.
2. For EBD malfunction, the EBD and ABS become inoperative, and the condition of the vehicle is the same
as the condition of vehicles without ABS/TCS/VDC or EBD system.
VDC/TCS SYSTEM
In case of TCS/VDC system malfunction, the VDC OFF indicator lamp and SLIP indicator lamp are turned on
and the condition of the vehicle is the same as the condition of vehicles without TCS/VDC system. In case of
an electrical malfunction with the TCS/VDC system, the ABS control continues to operate normally without
TCS/VDC control.
ACTIVE BOOSTER
The active brake booster consists of a vacuum booster, an active booster control group and a delta stroke
sensor. In case of brake booster system malfunction due to loss of vacuum, the delta stroke sensor will signal
the ABS actuator and electric unit (control unit) that a booster failure has occurred. The active booster then
applies supplemental force to the master cylinder relative to the amount of force exerted on the brake pedal.
Hydraulic Circuit DiagramINFOID:0000000003532774
WFIA0187E

BRC-10
< SERVICE INFORMATION >[VDC/TCS/ABS]
CAN COMMUNICATION
CAN COMMUNICATION
System DescriptionINFOID:0000000003532775
Refer to LAN-4.

TROUBLE DIAGNOSIS
BRC-11
< SERVICE INFORMATION >[VDC/TCS/ABS]
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TROUBLE DIAGNOSIS
How to Perform Trouble Diagnosis for Quick and Accurate RepairINFOID:0000000003532776
INTRODUCTION
The ABS/TCS/VDC system has an electronic control unit to control
major functions. The control unit accepts input signals from sensors
and controls actuator operation. It is also important to check for con-
ventional malfunctions such as air leaks in the booster or lines, lack
of brake fluid, or other malfunctions with the brake system.
It is much more difficult to diagnose a malfunction that occurs inter-
mittently rather than continuously. Most intermittent malfunctions are
caused by poor electrical connections or wiring. In this case, careful
checking of suspicious circuits may help prevent the replacement of
good parts.
A visual check only may not find the cause of the malfunction, so a
road test should be performed.
Before undertaking actual checks, take just a few minutes to talk with
a customer who approaches with an ABS/TCS/VDC complaint. The
customer is a very good source of information, especially for inter-
mittent malfunctions. Through the talks with the customer, find out
what symptoms are present and under what conditions they occur.
Start your diagnosis by looking for “conventional” malfunctions first.
This is one of the best ways to troubleshoot brake malfunctions on
an ABS/TCS/VDC equipped vehicle. Also check related Service Bul-
letins for information.
SEF233G
SEF234G

BRC-12
< SERVICE INFORMATION >[VDC/TCS/ABS]
TROUBLE DIAGNOSIS
WORK FLOW
CLARIFY CONCERN
WFIA0534E