2004 INFINITI QX56 power steering

EC-426Revision: August 2007
DTC P1229 SENSOR POWER SUPPLY
2004 QX56
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
Diagnostic ProcedureUBS00H9E
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-133, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
48 SBSensor power supply
(EVAP control system
pressure sensor)[Ignition switch: ON]Approximately 5V
49 R/YSensor power supply
(Refrigerant pressure
sensor)[Ignition switch: ON]Approximately 5V
68 W/LSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
90 LSensor power supply
(APP sensor 1)[Ignition switch: ON]Approximately 5V
BBIA0354E

DTC P1229 SENSOR POWER SUPPLY
EC-427
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Revision: August 20072004 QX56
2. CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness
connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminal 7 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
3. CHECK SENSOR POWER SUPPLY CIRCUITS
Check the following.

Harness for short to power and short to ground, between the following terminals
OK or NG
OK >> GO TO 4.
NG >> Repair short to ground or short to power in harness or connectors.
4. CHECK COMPONENTS
Check the following.

EVAP control system pressure sensor (Refer to EC-307, "Component Inspection" .)

Power steering pressure sensor (Refer to EC-350, "Component Inspection" .)

Refrigerant pressure sensor (Refer to EC-607, "REFRIGERANT PRESSURE SENSOR" .)
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning components.
5. CHECK ACCELERATOR PEEDAL POSITION SENSOR
Refer to EC-582, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
BBIA0361E
Voltage: Approximately 5V
PBIB2070E
ECM terminal Sensor terminal Reference Wiring Diagram
48 EVAP control system pressure sensor terminal 3EC-304
49 Refrigerant pressure sensor terminal 1EC-608
68 Power steering pressure sensor terminal 1EC-347
90 APP sensor terminal 7EC-425

DTC P1564 ICC STEERING SWITCH
EC-515
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Revision: August 20072004 QX56
2. CHECK ICC STEERING SWITCH GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect combination switch harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between combination switch terminal
15 and ECM terminal 67.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, E152

Harness connectors E19, F33

Combination switch (spiral cable)

Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK ICC STEERING SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 99 and combination switch terminal 14.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, E152

Combination switch (spiral cable)

Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
6. CHECK ICC STEERING SWITCH
Refer to EC-516, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> Replace ICC steering switch.Continuity should exist.
BBIA0469E
Continuity should exist.

DTC P1564 ASCD STEERING SWITCH
EC-521
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Revision: August 20072004 QX56
Diagnostic ProcedureUBS00HBD
1. CHECK ASCD STEERING SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch ON.
2. Select “MAIN SW”, “RESUME/ACC SW”, “SET SW” and “CANCEL SW” in “DATA MONITOR” mode with
CONSULT-II.
3. Check each item indication under the following conditions.
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 99 and ground with press-
ing each button.
OK or NG
OK >> GO TO 7.
NG >> GO TO 2.
2. CHECK ASCD STEERING SWITCH GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect combination switch harness connector.
4. Check harness continuity between combination switch terminal
15 and ECM terminal 67. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
Switch Monitor item Condition Indication
ON/OFF(MAIN)
switchMAIN SWPressed ON
Released OFF
ACCEL/RESUME
switchRESUME/ACC SWPressed ON
Released OFF
COAST/SET switch SET SWPressed ON
Released OFF
CANCEL switch CANCEL SW Pressed ON
Released OFF
SEC0 06 D
Switch Condition Voltage [V]
ON/OFF(MAIN) switchPressed Approx. 0
Released Approx. 4
ACCEL/RESUME switchPressed Approx. 3
Released Approx. 4
COAST/SET switchPressed Approx. 2
Released Approx. 4
CANCEL switchPressed Approx. 1
Released Approx. 4
PBIB0 311 E
Continuity should exist.
BBIA0362E

EC-522Revision: August 2007
DTC P1564 ASCD STEERING SWITCH
2004 QX56
3. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, E152

Harness connectors E19, F33

Combination switch (spiral cable)

Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK ASCD STEERING SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 99 and combination switch terminal 14.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, E152

Combination switch (spiral cable)

Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
6. CHECK ASCD STEERING SWITCH
Refer to EC-522, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> Replace ASCD steering switch.
7. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00HBE
ASCD STEERING SWITCH
1. Disconnect combination switch (spiral cable).
2. Check continuity between ASCD steering switch terminals 14
and 15 with pushing each switch.Continuity should exist.
Switch Condition Resistance [Ω]
ON/OFF(MAIN) switchPressed Approx. 0
Released Approx. 4,000
COAST/SET switchPressed Approx. 660
Released Approx. 4,000
PBIB1673E

AUTOMATIC SPEED CONTROL DEVICE (ASCD)
EC-647
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Revision: August 20072004 QX56
AUTOMATIC SPEED CONTROL DEVICE (ASCD)PFP:18930
System DescriptionUBS00HE7
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a driver to keep vehicle at predetermined constant speed
without pressing accelerator pedal. Driver can set vehicle speed in advance between approximately 40 km/h
(25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric throttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE indicator and SET indicator in combination meter. If any
malfunction occurs in ASCD system, it automatically deactivates control.
SET OPERATION
Press ON/OFF(MAIN) switch. (The CRUISE indicator in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press COAST/SET switch. (Then SET indicator in combination meter illuminates.)
ACCEL OPERATION
If the ACCEL/RESUME switch is pressed during cruise control driving, increase the vehicle speed until the
switch is released or vehicle speed reaches maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exist, cruise operation will be canceled.

CANCEL switch is pressed

More than 2 switches at ASCD steering switch are pressed at the same time (Set speed will be cleared)

Brake pedal is depressed

Selector lever is changed to N, P, R position

Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed

VDC/TCS system is operated
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.

Engine coolant temperature is slightly higher than the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by pressing COAST/SET switch or ACCEL/
RESUME switch.

Malfunction for some self-diagnoses regarding ASCD control: SET lamp will blink quickly.
If ON/OFF(MAIN) switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled
and vehicle speed memory will be erased.
COAST OPERATION
When the COAST/SET switch is pressed during cruise control driving, decrease vehicle set speed until the
switch is released. And then ASCD will keep the new set speed.
Sensor Input signal to ECM ECM function Actuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed controlElectric throttle control
actuator Stop lamp switch Brake pedal operation
ASCD steering switch ASCD steering switch operation
Park/Neutral position (PNP)
switchGear position
Combination meter* Vehicle speed
TCM* Powertrain revolution

EM-12Revision: August 2007
DRIVE BELTS
2004 QX56
DRIVE BELTSPFP:02117
Checking Drive BeltsEBS00ILA
WAR NIN G:
Be sure to perform when the engine is stopped.
1. Remove the air duct and resonator assembly when inspecting the drive belt. Refer to EM-14, "
Removal
and Installation" .
2. Make sure that the indicator (single line notch) of each auto tensioner is within the allowable working
range (between three line notches).
NOTE:

Check the auto tensioner indication when the engine is cold.

When the new drive belt is installed, the range should be as shown.

The indicator notch is located on the moving side of the auto tensioner.
3. Visually check the entire belt for wear, damage or cracks.
4. If the indicator is out of allowable working range or belt is damaged, replace the belt.
Tension AdjustmentEBS00ILB
Belt tensioning is not necessary, as it is automatically adjusted by the auto tensioner.
Removal and InstallationEBS00ILC
DRIVE BELT
Removal
1. Remove the air duct and resonator assembly. Refer to EM-14, "Removal and Installation" .
2. Install Tool on auto tensioner pulley bolt, move in the direction of
arrow (loosening direction of tensioner) as shown.
CAUTION:
Avoid placing hand in a location where pinching may occur
if the tool accidentally comes off.
3. Remove the drive belt.
LBIA0391E
1. Drive belt 2. Power steering pump pulley 3. Generator pulley
4. Crankshaft pulley 5. A/C compressor 6. Idler pulley
7. Cooling fan pulley 8. Water pump pulley 9. Drive belt tensioner
Tool number : — (J-46535)
WBIA0537E

EM-36Revision: August 2007
TIMING CHAIN
2004 QX56
NOTE:

To remove timing chain and associated parts, start with those on the left bank. The procedure for remov-
ing parts on the right bank is omitted because it is the same as that for removal on the left bank.

To install timing chain and associated parts, start with those on the right bank. The procedure for installing
parts on the left bank is omitted because it is the same as that for installation on the right bank.
REMOVAL
1. Remove the engine assembly from the vehicle. Refer to EM-70, "REMOVAL" .
2. Remove the following components and related parts:

Drive belt auto tensioner and idler pulley. Refer to EM-12, "DRIVE BELTS" .

Thermostat housing and water hose. Refer to CO-17, "Removal of Thermostat Housing, Water Outlet
and Heater Pipe" .

Power steering pump bracket. Refer to PS-26, "REMOVAL" .

Oil pan (lower), (upper) and oil strainer. Refer to EM-22, "OIL PAN AND OIL STRAINER" .

Ignition coil. Refer to EM-26, "IGNITION COIL" .

Rocker cover. Refer to EM-33, "ROCKER COVER" .
3. Remove the chain case cover (right bank) and (left bank).
a. Loosen and remove the bolts in the reverse order shown.
b. Cut the liquid gasket to remove covers using Tool.
CAUTION:
Do not damage mating surfaces.
4. Obtain compression TDC of No. 1 cylinder as follows:
a. Turn crankshaft pulley clockwise to align the TDC identification
notch (without paint mark) with timing indicator on front cover.
1. Camshaft sprocket (left bank EXH) 2. Camshaft sprocket (left bank INT) 3. Camshaft sprocket (right bank INT)
4. Camshaft sprocket (right bank EXH) 5. Front cover 6. Chain case cover (right bank)
7. Chain case cover (left bank) 8. Crankshaft pulley bolt 9. Crankshaft pulley
10. Chain tensioner cover 11. Front oil seal 12. Oil pump drive spacer
13. Oil pump assembly 14. Crankshaft sprocket 15. Bracket
16. O-ring 17. Timing chain tension guide (right
bank)18. Timing chain slack guide (right bank)
19. Timing chain (right bank) 20. Timing chain (left bank) 21. Chain tensioner (right bank)
22. Timing chain slack guide (left bank) 23. Timing chain tension guide (left
bank)24. Chain tensioner (left bank)
Tool number: KV10111100 (J-37228)
KBIA2475E
KBIA2476E