2004 INFINITI QX56 steering

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

DTC P1564 ASCD STEERING SWITCH
EC-523
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Revision: August 20072004 QX56
ACCEL/RESUME switchPressed Approx. 1,480
Released Approx. 4,000
CANCEL switchPressed Approx. 250
Released Approx. 4,000 Switch Condition Resistance [Ω]

EC-524Revision: August 2007
DTC P1568 ICC FUNCTION
2004 QX56
DTC P1568 ICC FUNCTIONPFP:18995
On Board Diagnosis LogicUBS00HYW
NOTE:

If DTC P1568 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .

If DTC P1568 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-351, "
DTC P0605 ECM".

This self-diagnosis has the one trip detection logic.

The MIL will not light up for this self-diagnosis.
DTC Confirmation ProcedureUBS00HYX
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
Step 4 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test
is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Press ON/OFF (MAIN) switch on ICC steering switch.
4. Drive the vehicle at more than 40 km/h (25 MPH).
5. Press COAST/SET switch.
6. If DTC is detected, go to EC-524, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic ProcedureUBS00HYY
1. REPLACE ICC UNIT
1. Replace ICC unit.
2. Perform ACS-9, "
ACTION TEST" .
3. Check DTC of ICC unit. Refer to ACS-36, "
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS" .
>>INSPECTION END
DTC No. Trouble Diagnosis Name DTC Detecting Condition Possible Cause
P1568
1568ICC functionECM detects a difference between signals
from ICC unit is out of specified range.

Harness or connectors
(The CAN communication line is open or
shorted.)

ICC unit

ECM
SEF 0 58 Y

EC-628Revision: August 2007
ASCD INDICATOR
2004 QX56
ASCD INDICATORPFP:24814
Component DescriptionUBS00HDT
ASCD indicator lamp illuminates to indicate ASCD operation status. Lamp has two indicators, CRUISE and
SET, and is integrated in combination meter.
CRUISE indicator illuminates when ON/OFF switch on ASCD steering switch is turned ON to indicated that
ASCD system is ready for operation.
SET indicator illuminates when following conditions are met.

CRUISE indicator is illuminated.

SET switch on ASCD steering switch is turned ON while vehicle speed is within the range of ASCD set-
ting.
SET indicator remains lit during ASCD control.
Refer to EC-647, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)" for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeUBS00HDU
Specification data are reference value.
MONITOR ITEM CONDITION SPECIFICATION
CRUISE LAMP

Ignition switch: ON
ON/OFF(MAIN) switch: Pressed
at the 1st time → at the 2nd timeON → OFF
SET LAMP

ON/OFF switch: ON

When vehicle speed is
between 40 km/h (25 MPH)
and 144 km/h (89 MPH)

COAST/SET switch: Pressed ON

COAST/SET switch: Released OFF

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

EC-648Revision: August 2007
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
2004 QX56
RESUME OPERATION
When the ACCEL/RESUME switch is pressed after cancel operation other than pressing ON/OFF(MAIN)
switch is performed, vehicle speed will return to last set speed. To resume vehicle set speed, vehicle condition
must meet following conditions.

Brake pedal is released

A/T selector lever is in other than P and N positions

Vehicle speed is greater than 40 km/h (25 MPH) and less than 144 km/h (89 MPH)
Component DescriptionUBS00HE8
ASCD STEERING SWITCH
Refer to EC-517 .
ASCD BRAKE SWITCH
Refer to EC-534 , and EC-621 .
STOP LAMP SWITCH
Refer to EC-534 , EC-551 and EC-621 .
ELECTRIC THROTTLE CONTROL ACTUATOR
Refer to EC-365 , EC-367 , EC-373 and EC-378 .
ASCD INDICATOR
Refer to EC-628 .

SERVICE DATA AND SPECIFICATIONS (SDS)
EC-649
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Revision: August 20072004 QX56
SERVICE DATA AND SPECIFICATIONS (SDS)PFP:00030
Fuel PressureUBS00HE9
Idle Speed and Ignition TimingUBS00HEA
*1: Under the following conditions:

Air conditioner switch: OFF

Electric load: OFF (Lights and heater fan)

Steering wheel: Kept in straight-ahead position
Calculated Load ValueUBS00HEB
Mass Air Flow SensorUBS00HEC
*: Engine is warmed up to normal operating temperature and running under no-load.
Intake Air Temperature SensorUBS00HED
Engine Coolant Temperature SensorUBS00HEE
A/F Sensor 1 HeaterUBS00HEF
Heated Oxygen sensor 2 HeaterUBS00HEG
Crankshaft Position Sensor (POS)UBS00HEH
Refer to EC-260, "Component Inspection" .
Camshaft Position Sensor (PHASE)UBS00HEI
Refer to EC-266, "Component Inspection" .
Throttle Control MotorUBS00HEJ
Fuel pressure at idling kPa (kg/cm2 , psi)Approximately 350 (3.57, 51)
Target idle speed
No-load*1 (in P or N position)650±50 rpm
Air conditioner: ON In P or N position 700 rpm or more
Ignition timing In P or N position 15° ± 5° BTDC
Condition Calculated load value % (Using CONSULT-II or GST)
At idle14.0 - 33.0
At 2,500 rpm12.0 - 25.0
Supply voltage Battery voltage (11 - 14V)
Output voltage at idle1.1 - 1.4V*
Mass air flow (Using CONSULT-II or GST)3.0 - 9.0 g·m/sec at idle*
9.0 - 28.0 g·m/sec at 2,500 rpm*
Temperature °C (°F) Resistance kΩ
25 (77)1.9 - 2.1
80 (176)0.31 - 0.37
Temperature °C (°F) Resistance kΩ
20 (68)2.1 - 2.9
50 (122)0.68 - 1.00
90 (194)0.236 - 0.260
Resistance [at 25°C (77°F)] 3.3 - 4.3Ω
Resistance [at 25°C (77°F)] 5.0 - 7.0Ω
Resistance [at 25°C (77°F)] Approximately 1 - 15Ω

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