2004 INFINITI QX56 Engine Control System

AUTOMATIC BACK DOOR SYSTEM
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Trouble Diagnosis ProcedureEIS002T0
1. Check the symptom and customer's requests.
2. Understand outline of system. Refer to BL-45, "
System Description" .
3. Confirm system operation.
4. Perform self-diagnosis procedures. Refer to BL-115, "
Self-Diagnosis Procedures" .
5. Refer to diagnosis chart by symptom, repair or replace any malfunctioning parts. Refer to BL-116, "
Diag-
nosis Chart" .
6. Inspection End.
Self-Diagnosis ProceduresEIS005X4
INPUT SIGNAL CHECK MODE
Input signal check mode allows testing of switch input signal to the back door control unit.
To activate input signal check mode on the automatic back door, perform the following steps:
1. Turn ignition switch OFF.
2. Turn back door close switch to CANCEL (system cancelled).
3. Place A/T selector lever in P position.
4. Using the inside emergency release lever, open the back door.
5. Have an assistant press and hold the back door handle switch.
6. While the assistant continues to hold the back door handle switch, turn ignition switch ON (DO NOT start
engine).
7. After approximately 5 seconds, the back door warning chime will sound for 0.5 seconds.
8. Release the back door handle switch.
9. Within 8 seconds of the back door warning chime sounding, press and hold the power liftgate switch.
10. After approximately 5 seconds, the back door warning chime will sound for 1 second.
11. Release the power liftgate switch.
12. The input signal check mode is now initialized.
The input signal check mode can test the following inputs. The back door warning chime will sound for approx-
imately 0.5 seconds each time a switch signal input occurs. Use this test when one of these inputs is not
responding during normal automatic back door operation.
*Back door warning chime should sound as soon as vehicle moves.
Turn ignition switch OFF to end input signal check mode.
OPERATING CHECK MODE
Operating check mode allows self-diagnosis of the automatic back door system.
To activate operating check mode on the automatic back door, perform the following steps:
1. Turn ignition switch OFF.
2. Turn back door close switch to CANCEL (system cancelled).
3. Place A/T selector lever in P position.
Switch signal Operation Refer to
Power liftgate switch OFF → ONBL-118
Back door close switch (CLOSE) OFF → ONBL-120
Back door close switch (CANCEL) OFF → ONBL-121
Back door handle switch OFF → ONBL-127
Glass switch OFF → ONBL-36
A/T device (park switch) P position → other than P positionAT- 1 9 1
Vehicle speed* Vehicle speedAT-6 8
Remote keyless entry signal Keyfob switch OFF → ONBL-66
Door lock/unlock signal LOCK → UNLOCKBL-34
Pinch strip LH signal OFF → ONBL-122
Pinch strip RH signal OFF → ONBL-122

IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM-NATS)
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System DescriptionEIS002TM
IVIS (Infiniti Vehicle Immobilizer System-NATS) has the following immobilizer functions:

Since only IVIS (NATS) ignition keys, whose IDs have been registered into the ECM and BCM, allow the
engine to run, operation of a stolen vehicle without an IVIS (NATS) registered key is prevented by IVIS
(NATS).
IVIS (NATS) will immobilize the engine if someone tries to start it without the registered key of IVIS
(NATS).

All of the originally supplied ignition key IDs have been IVIS (NATS) registered.
If requested by the vehicle owner, a maximum of five key IDs can be registered into the IVIS (NATS) com-
ponents.

The security indicator blinks when the ignition switch is in OFF or ACC position. IVIS (NATS) warns out-
siders that the vehicle is equipped with the anti-theft system.

When IVIS (NATS) detects a malfunction, the security indicator lamp lights up while ignition key is in the
ON position.

IVIS (NATS) trouble diagnoses, system initialization and additional registration of other IVIS (NATS) igni-
tion key IDs must be carried out using CONSULT-II hardware and CONSULT-II IVIS (NATS) software.
When IVIS (NATS) initialization has been completed, the ID of the inserted ignition key is automatically
IVIS (NATS) registered. Then, if necessary, additional registration of other IVIS (NATS) ignition key IDs
can be carried out.
Regarding the procedures of IVIS (NATS) initialization and IVIS (NATS) ignition key ID registration, refer
to CONSULT-II Operation Manual NATS-IVIS/NVIS.

When servicing a malfunction of the IVIS (NATS) (indicated by lighting up of Security Indicator
Lamp) or registering another IVIS (NATS) ignition key ID, it may be necessary to re-register origi-
nal key identification. Therefore, be sure to receive ALL KEYS from vehicle owner.
System CompositionEIS0 02 T N
The immobilizer function of the IVIS (NATS) consists of the following:

NATS ignition key

NATS antenna amp. located in the ignition key cylinder

Body control module (BCM)

Engine control module (ECM)

Security indicator
NOTE:
The communication between ECM and BCM uses the CAN communication system.
PIIA1121E

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IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM-NATS)
Revision: August 20072004 QX56
ECM Re-communicating FunctionEIS002TO
The following procedure can automatically perform re-communication of ECM and BCM, but only when the
ECM has been replaced with a new one which has never been energized on-board.
(In this step, initialization procedure by CONSULT-II is not necessary)
NOTE:

When registering new key IDs or replacing the ECM other than brand new, refer to CONSULT-II
Operation Manual NATS-IVIS/NVIS.

If multiple keys are attached to the key holder, separate them before work.

Distinguish keys with unregistered key ID from those with registered ID.
1. Install ECM.
2. Using a registered key (*1), turn ignition switch to ON.
*1: To perform this step, use the key that has been used before performing ECM replacement.
3. Maintain ignition switch in ON position for at least 5 seconds.
4. Turn ignition switch to OFF.
5. Start engine.
If engine can be started, procedure is completed.
If engine cannot be started, refer to CONSULT-II Operation Manual NATS-IVIS/NVIS and initialize control
unit.

IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM-NATS)
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Diagnostic Procedure 6EIS002TZ
“SECURITY INDICATOR LAMP DOES NOT LIGHT UP”
1. CHECK FUSE
Check 10A fuse [No.19, located in the fuse block (J/B)]
OK or NG
OK >> GO TO 2.
NG >> If fuse is blown, be sure to eliminate cause of malfunction before installing new fuse.
2. CHECK SECURITY INDICATOR LAMP
1. Start engine and turn ignition switch OFF.
2. Check the security indicator lamp lights up.
OK or NG
OK >> Inspection End.
NG >> GO TO 3.
3. CHECK SECURITY INDICATOR LAMP POWER SUPPLY CIRCUIT
1. Disconnect security indicator lamp.
2. Check voltage between security indicator lamp connector M24
terminal 8 and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace harness.
4. CHECK BCM (NATS CONTROL UNIT) FUNCTION
1. Connect security indicator lamp.
2. Disconnect BCM.
3. Check voltage between BCM connector M18 terminal 23 and
ground.
OK or NG
OK >> BCM is malfunctioning.

Replace BCM.
Ref. part No. A

Perform initialization with CONSULT-II.

For initialization, refer to “CONSULT-II Operation
Manual NATS-IVIS/NVIS”.
NG >> Check the following:

Harness for open or short between security indicator lamp and BCM (NATS control unit).

Indicator lamp condition Security indicator lamp should light up.
8 (Y/R) - Ground : Battery voltage
LIIA1072E
23 (G/O) - Ground : Battery voltage
LIIA0523E

BRC-1
BRAKE CONTROL SYSTEM
F BRAKES
CONTENTS
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SECTION BRC
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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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BRC
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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)" .