2004 INFINITI QX56 steering

BRC-62
[VDC/TCS/ABS]
ON-VEHICLE SERVICE
Revision: August 20072004 QX56
ON-VEHICLE SERVICEPFP:00000
Adjustment of Steering Angle Sensor Neutral PositionEFS003RM
After removing/installing or replacing ABS actuator and electric unit (control unit), steering angle sensor, steer-
ing and suspension components which affect wheel alignment or after adjusting wheel alignment, be sure to
adjust neutral position of steering angle sensor before running vehicle.
NOTE:
Adjustment of steering angle sensor neutral position requires CONSULT-II.
1. Stop vehicle with front wheels in straight-ahead position.
2. Connect CONSULT-II to data link connector on vehicle, and turn
ignition switch ON (do not start engine).
3. Touch “ABS”, “WORK SUPPORT” and “ST ANGLE SENSOR
ADJUSTMENT” on CONSULT-II screen in this order.
4. Touch “START”.
CAUTION:
Do not touch steering wheel while adjusting steering angle
sensor.
5. After approximately 10 seconds, touch “END”. (After approxi-
mately 60 seconds, it ends automatically.)
6. Turn ignition switch OFF, then turn it ON again.
7. Run vehicle with front wheels in straight-ahead position, then
stop.
8. Select “DATA MONITOR”, “SELECTION FROM MENU”, and
“STR ANGLE SIG” on CONSULT-II screen. Then check that
“STR ANGLE SIG” is within 0±3.5 deg. If value is more than specification, repeat steps 1 to 5.
9. Erase memory of ABS actuator and electric unit (control unit) and ECM.
10. Turn ignition switch to OFF.
Calibration of Decel G SensorEFS003RN
After removing/installing or replacing ABS actuator and electric unit (control unit), yaw rate/side/decel G sen-
sor, steering and suspension components which affect wheel alignment or after adjusting wheel alignment, be
sure to calibrate the decel G sensor before running vehicle.
NOTE:
Calibration of decel G sensor requires CONSULT-II.
1. Stop vehicle with front wheels in straight-ahead position.
CAUTION:

The work should be done on a level area with an unloaded vehicle.

Keep all the tires inflated to the correct pressures. Adjust the tire pressure to the specified pres-
sure value.
2. Connect CONSULT-II with CONSULT-II CONVERTER to data link connector on vehicle, and turn ignition
switch ON (do not start engine).
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.
3. Touch "ABS", "WORK SUPPORT" and "DECEL G SEN CALIBRATION" on CONSULT-II screen in this
order. Refer to BRC-28, "
CONSULT-II BASIC OPERATION PROCEDURE" .
BBIA0369E
WFIA0239E

ACTUATOR AND ELECTRIC UNIT (ASSEMBLY)
BRC-67
[VDC/TCS/ABS]
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BRC
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" .

BRC-68
[VDC/TCS/ABS]
STEERING ANGLE SENSOR
Revision: August 20072004 QX56
STEERING ANGLE SENSORPFP:25554
Removal and InstallationEFS003RR
The steering angle sensor is an integral part of the spiral cable. Refer to SRS-47, "Removal and Installation" .
CAUTION:
After installation of spiral cable, adjust steering angle sensor. Refer to BRC-62, "
Adjustment of Steer-
ing Angle Sensor Neutral Position" .

EC-6Revision: August 20072004 QX56 Component Inspection ..........................................503
Removal and Installation ......................................503
DTC P1446 EVAP CANISTER VENT CONTROL
VALVE .....................................................................504
Component Description ........................................504
CONSULT-II Reference Value in Data Monitor Mode
.504
On Board Diagnosis Logic ....................................504
DTC Confirmation Procedure ...............................505
Wiring Diagram .....................................................506
Diagnostic Procedure ...........................................507
Component Inspection ..........................................508
DTC P1564 ICC STEERING SWITCH ....................510
Component Description ........................................510
CONSULT-II Reference Value in Data Monitor Mode
.510
On Board Diagnosis Logic ....................................510
DTC Confirmation Procedure ...............................510
Wiring Diagram .....................................................512
Diagnostic Procedure ...........................................514
Component Inspection ..........................................516
DTC P1564 ASCD STEERING SWITCH ................517
Component Description ........................................517
CONSULT-II Reference Value in Data Monitor Mode
.517
On Board Diagnosis Logic ....................................517
DTC Confirmation Procedure ...............................518
Wiring Diagram .....................................................519
Diagnostic Procedure ...........................................521
Component Inspection ..........................................522
DTC P1568 ICC FUNCTION ...................................524
On Board Diagnosis Logic ....................................524
DTC Confirmation Procedure ...............................524
Diagnostic Procedure ...........................................524
DTC P1572 ICC BRAKE SWITCH ..........................525
Component Description ........................................525
CONSULT-II Reference Value in Data Monitor Mode
.525
On Board Diagnosis Logic ....................................525
DTC Confirmation Procedure ...............................525
Wiring Diagram .....................................................527
Diagnostic Procedure ...........................................528
Component Inspection ..........................................532
DTC P1572 ASCD BRAKE SWITCH ......................534
Component Description ........................................534
CONSULT-II Reference Value in Data Monitor Mode
.534
On Board Diagnosis Logic ....................................534
DTC Confirmation Procedure ...............................535
Wiring Diagram .....................................................536
Diagnostic Procedure ...........................................537
Component Inspection ..........................................541
DTC P1574 ICC VEHICLE SPEED SENSOR .........542
Component Description ........................................542
On Board Diagnosis Logic ....................................542
DTC Confirmation Procedure ...............................542
Diagnostic Procedure ...........................................543
DTC P1574 ASCD VEHICLE SPEED SENSOR .....544
Component Description ........................................544On Board Diagnosis Logic .................................... 544
DTC Confirmation Procedure ................................ 544
Diagnostic Procedure ............................................ 545
DTC P1706 PNP SWITCH ....................................... 546
Component Description ........................................ 546
CONSULT-II Reference Value in Data Monitor Mode
. 546
On Board Diagnosis Logic .................................... 546
DTC Confirmation Procedure ................................ 546
Overall Function Check ......................................... 547
Wiring Diagram ..................................................... 548
Diagnostic Procedure ............................................ 549
DTC P1805 BRAKE SWITCH ................................. 551
Description ............................................................ 551
CONSULT-II Reference Value in Data Monitor Mode
. 551
On Board Diagnosis Logic .................................... 551
DTC Confirmation Procedure ................................ 551
Wiring Diagram ..................................................... 552
Diagnostic Procedure ............................................ 553
Component Inspection .......................................... 555
DTC P2122, P2123 APP SENSOR ......................... 556
Component Description ........................................ 556
CONSULT-II Reference Value in Data Monitor Mode
. 556
On Board Diagnosis Logic .................................... 556
DTC Confirmation Procedure ................................ 557
Wiring Diagram ..................................................... 558
Diagnostic Procedure ............................................ 559
Component Inspection .......................................... 561
Removal and Installation ....................................... 561
DTC P2127, P2128 APP SENSOR ......................... 562
Component Description ........................................ 562
CONSULT-II Reference Value in Data Monitor Mode
. 562
On Board Diagnosis Logic .................................... 562
DTC Confirmation Procedure ................................ 563
Wiring Diagram ..................................................... 564
Diagnostic Procedure ............................................ 565
Component Inspection .......................................... 568
Removal and Installation ....................................... 568
DTC P2135 TP SENSOR ........................................ 569
Component Description ........................................ 569
CONSULT-II Reference Value in Data Monitor Mode
. 569
On Board Diagnosis Logic .................................... 569
DTC Confirmation Procedure ................................ 570
Wiring Diagram ..................................................... 571
Diagnostic Procedure ............................................ 572
Component Inspection .......................................... 575
Removal and Installation ....................................... 575
DTC P2138 APP SENSOR ...................................... 576
Component Description ........................................ 576
CONSULT-II Reference Value in Data Monitor Mode
. 576
On Board Diagnosis Logic .................................... 576
DTC Confirmation Procedure ................................ 577
Wiring Diagram ..................................................... 578
Diagnostic Procedure ............................................ 579

ENGINE CONTROL SYSTEM
EC-25
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EC
Revision: August 20072004 QX56
System ChartUBS00GZD
*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This sensor is not used to control the engine system under normal conditions.
*3: This input signal is sent to the ECM through CAN communication line.
*4: This output signal is sent from the ECM through CAN communication line.Input (Sensor) ECM Function Output (Actuator)

Camshaft position sensor (PHASE)

Crankshaft position sensor (POS)

Mass air flow sensor

Engine coolant temperature sensor

A/F sensor 1

Throttle position sensor

Accelerator pedal position sensor

Park/neutral position (PNP) switch

Intake air temperature sensor

Power steering pressure sensor

Ignition switch

Battery voltage

Knock sensor

Refrigerant pressure sensor

Stop lamp switch

ASCD steering switch

ASCD brake switch

Fuel level sensor*1 *3

EVAP control system pressure sensor

Fuel tank temperature sensor*1

Heated oxygen sensor 2*2

TCM (Transmission control module)*3

ABS actuator and electric unit (control unit)*3

Air conditioner switch*3

Wheel sensor*3

Electrical load signal*3
Fuel injection & mixture ratio control Fuel injector
Electronic ignition system Power transistor
Nissan torque demand control system

Electric throttle control actuator

Fuel injector
Fuel pump control Fuel pump relay
ASCD vehicle speed control Electric throttle control actuator
On board diagnostic system
MIL (On the instrument panel)*
4
A/F sensor 1 heater control A/F sensor 1 heater
Heated oxygen sensor 2 heater control Heated oxygen sensor 2 heater
EVAP canister purge flow controlEVAP canister purge volume control
solenoid valve
Air conditioning cut control
Air conditioner relay*
4
Cooling fan control
Cooling fan relay*4
ON BOARD DIAGNOSIS for EVAP system EVAP canister vent control valve

EC-26Revision: August 2007
ENGINE CONTROL SYSTEM
2004 QX56
Multiport Fuel Injection (MFI) SystemUBS00GZE
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor (POS), camshaft
position sensor (PHASE) and the mass air flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.


During warm-up

When starting the engine

During acceleration

Hot-engine operation

When selector lever is changed from N to D

High-load, high-speed operation


During deceleration

During high engine speed operation
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
A/F sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Knock sensor Engine knocking condition
Battery
Battery voltage*
3
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit)*
2VDC/TCS operation command
Air conditioner switch*
2Air conditioner operation
Wheel sensor*
2Vehicle speed

ENGINE CONTROL SYSTEM
EC-29
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EC
Revision: August 20072004 QX56

At idle

At low battery voltage

During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Nissan Torque Demand (NTD) Control SystemUBS00GZG
INPUT/OUTPUT SIGNAL CHART
*1: Signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
NTD control system decides the target traction based on the accelerator operation status and the current driv-
ing condition. It then selects the engine torque target by correcting running resistance and atmospheric pres-
sure, and controlling the power-train. Using electric throttle control actuator, it achieves the engine torque
development target which corresponds linearly to the driver's accelerator operation.
Running resistance correction control compares the engine torque estimate value, measured vehicle acceler-
ation, and running resistance on a flat road, and estimates vehicle weight gain and running resistance varia-
tion caused by slopes to correct the engine torque estimate value.
Atmospheric pressure correction control compares the engine torque estimate value from the airflow rate and
the target engine torque for the target traction, and estimates variation of atmospheric pressure to correct the
target engine torque. This system achieves powerful driving without reducing engine performance in the prac-
tical speed range in mountains and high-altitude areas.
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
NTD controlElectric throttle con-
trol actuator and fuel
injector Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/Neutral position (PNP) switch Gear position
Power steering pressure sensor Power steering operation
Battery Battery voltage
TCM (CAN communication) A/T control signal
Air conditioner switch*
1Air conditioner operation
ABS actuator and electric unit (control unit)*
1VDC/TCS/ABS operation
Wheel sensor*
1Vehicle speed
Electrical load*
1Electrical load signal

EC-30Revision: August 2007
ENGINE CONTROL SYSTEM
2004 QX56
Air Conditioning Cut ControlUBS00GZH
INPUT/OUTPUT SIGNAL CHART
*1: Signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.

When the accelerator pedal is fully depressed.

When cranking the engine.

At high engine speeds.

When the engine coolant temperature becomes excessively high.

When operating power steering during low engine speed or low vehicle speed.

When engine speed is excessively low.

When refrigerant pressure is excessively low or high.
Fuel Cut Control (at No Load and High Engine Speed)UBS00GZI
INPUT/OUTPUT SIGNAL CHART
*1: Signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 1,400 rpm under no load (for example, the shift position is neutral and engine
speed is over 1,400 rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies
based on engine speed.
Fuel cut will be operated until the engine speed reaches 1,000 rpm, then fuel cut will be cancelled.
NOTE:
This function is different from deceleration control listed under Multiport Fuel Injection (MFI) System, EC-26
.
Sensor Input signal to ECM ECM function Actuator
Air conditioner switch*
1Air conditioner ON signal
Air conditioner
cut controlAir conditioner relay Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed*
2
Engine coolant temperature sensor Engine coolant temperature
Battery
Battery voltage*
2
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
Wheel sensor*
1Vehicle speed
Sensor Input signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut control Fuel injector Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed
Wheel sensor*
1Vehicle speed