2004 INFINITI QX56 steering wheel

TROUBLE DIAGNOSIS
EC-97
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Revision: August 20072004 QX563LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
4 L/W Throttle control motor (Close)[Ignition switch: ON]

Engine stopped

Shift lever position: D

Accelerator pedal: Released0 - 14V
5 L/B Throttle control motor (Open)[Ignition switch: ON]

Engine stopped

Shift lever position: D

Accelerator pedal: Fully depressed0 - 14V
6GRHeated oxygen sensor 2
heater (bank 1)[Engine is running]

Engine speed is below 3,600 rpm after the
following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load0 - 1.0V
[Ignition switch: ON]

Engine stopped
[Engine is running]

Engine speed is above 3,600 rpm.BATTERY VOLTAGE
(11 - 14V)
12 RPower steering pressure
sensor[Engine is running]

Steering wheel is being turned.0.5 - 4.5V
[Engine is running]

Steering wheel is not being turned.0.4 - 0.8V
13 OCrankshaft position sensor
(POS)[Engine is running]

Warm-up condition

Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle.1.0 - 2.0V
[Engine is running]

Engine speed is 2,000 rpm.1.0 - 2.0V TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
PBIB1104E
PBIB1105E
PBIB1041E
PBIB1042E

TROUBLE DIAGNOSIS
EC-119
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Revision: August 20072004 QX56
PW/ST SIGNAL
Engine: After warming up, idle
the engineSteering wheel is in neutral position.
(Forward direction)OFF
Steering wheel is turned. ON
LOAD SIGNAL

Ignition switch: ONRear window defogger switch is ON
and/or lighting switch is in 2nd.ON
Rear window defogger switch is OFF
and lighting switch is OFF.OFF
IGNITION SW

Ignition switch: ON → OFF → ON ON → OFF → ON
HEATER FAN SW

Engine: After warming up, idle
the engineHeater fan is operating. ON
Heater fan is not operating OFF
BRAKE SW

Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
INJ PULSE-B1
INJ PULSE-B2

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 2.0 - 2.8 msec
2,000 rpm 1.9 - 2.9 msec
IGN TIMING

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 14° - 18° BTDC
2,000 rpm 25° - 45° BTDC
CAL/LD VALUE

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 14% - 33%
2,500 rpm 12% - 25%
MASS AIRFLOW

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 3.0 - 9.0 g·m/s
2,500 rpm 9.0 - 28.0 g·m/s
PURG VOL C/V

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle
(Accelerator pedal is not depressed
even slightly, after starting engine)0%
2,000 rpm —
AIR COND RLY

Engine: After warming up, idle
the engineAir conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates)ON
FUEL PUMP RLY

For 1 second after turning ignition switch ON

Engine running or crankingON

Except above conditions OFF
VENT CONT/V

Ignition switch: ON OFF
THRTL RELAY

Ignition switch: ON ON
COOLING FAN

Engine: After warming up, idle
the engine

Air conditioner switch: OFFEngine coolant temperature is 99°C
(210°F) or lessOFF
Engine coolant temperature is
between 100°C (212°F) and 104°C
(219°F) at vehicle speed less than 40
km/h (25 MPH)ON
Engine coolant temperature is 105°C
(221°F) or moreON MONITOR ITEM CONDITION SPECIFICATION

TROUBLE DIAGNOSIS - SPECIFICATION VALUE
EC-123
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Revision: August 20072004 QX56
TROUBLE DIAGNOSIS - SPECIFICATION VALUEPFP:00031
DescriptionUBS00H09
The specification (SP) value indicates the tolerance of the value that is displayed in “DATA MONITOR (SPEC)”
mode of CONSULT-II during normal operation of the Engine Control System. When the value in “DATA MONI-
TOR (SPEC)” mode is within the SP value, the Engine Control System is confirmed OK. When the value in
“DATA MONITOR (SPEC)” mode is NOT within the SP value, the Engine Control System may have one or
more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:

B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board cor-
rection)

A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)

MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionUBS00H0A

Vehicle driven distance: More than 5,000 km (3,017 miles)

Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm2 , 14.25 - 15.12 psi)

Atmospheric temperature: 20 - 30°C (68 - 86°F)

Engine coolant temperature: 75 - 95°C (167 - 203°F)

Transmission: Warmed-up*1

Electrical load: Not applied*2

Engine speed: Idle
*1: After the engine is warmed up to normal operating temperature, drive vehicle until “FLUID TEMP SE” (A/T
fluid temperature sensor signal) indicates more than 60°C (140°F).
*2: Rear window defogger switch, air conditioner switch, lighting switch are OFF. Steering wheel is straight
ahead.
Inspection ProcedureUBS00H0B
NOTE:
Perform “DATA MONITOR (SPEC)” mode in maximum scale display.
1. Perform EC-79, "
Basic Inspection" .
2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL”, “A/F ALPHA-B1”, “A/F ALPHA-B2”
and “MAS A/F SE-B1” in “DATA MONITOR (SPEC)” mode with
CONSULT-II.
4. Make sure that monitor items are within the SP value.
5. If NG, go to EC-124, "
Diagnostic Procedure" .
SEF 6 01 Z

EC-346Revision: August 2007
DTC P0550 PSP SENSOR
2004 QX56
DTC P0550 PSP SENSORPFP:49763
Component DescriptionUBS00H6P
Power steering pressure (PSP) sensor is installed to the power
steering high-pressure tube and detects a power steering load. This
sensor is a potentiometer which transforms the power steering load
into output voltage, and emits the voltage signal to the ECM. The
ECM controls the electric throttle control actuator and adjusts the
throttle valve opening angle to increase the engine speed and
adjusts the idle speed for the increased load.
CONSULT-II Reference Value in Data Monitor ModeUBS00H6Q
Specification data are reference values.
On Board Diagnosis LogicUBS00H6R
The MIL will not light up for this diagnosis.
NOTE:
If DTC P0550 is displayed with DTC P1229, first perform the trouble diagnosis for DTC P1229. Refer to
EC-424, "
DTC P1229 SENSOR POWER SUPPLY" .
DTC Confirmation ProcedureUBS00H6S
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.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for at least 5 seconds.
4. If 1st trip DTC is detected, go to EC-348, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
BBIA0365E
MONITOR ITEM CONDITION SPECIFICATION
PW/ST SIGNAL

Engine: After warming up, idle
the engineSteering wheel is in neutral position.
(Forward direction)OFF
Steering wheel is turned. ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0550
0550Power steering pressure
sensor circuitAn excessively low or high voltage from the
sensor is sent to ECM.

Harness or connectors
(The sensor circuit is open or shorted)

Power steering pressure sensor
SEF 0 58 Y

EC-348Revision: August 2007
DTC P0550 PSP SENSOR
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 ProcedureUBS00H6U
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)
12 RPower steering pressure
sensor[Engine is running]

Steering wheel is being turned.0.5 - 4.5V
[Engine is running]

Steering wheel is not being turned.0.4 - 0.8V
67 B Sensor ground[Engine is running]

Warm-up condition

Idle speedApproximately 0V
68 W/LSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
BBIA0354E

EC-350Revision: August 2007
DTC P0550 PSP SENSOR
2004 QX56
6. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00H6V
POWER STEERING PRESSURE SENSOR
1. Reconnect all harness connectors disconnected.
2. Start engine and let it idle.
3. Check voltage between ECM terminal 12 and ground under the
following conditions.
Removal and Installation UBS00H6W
POWER STEERING PRESSURE SENSOR
Refer to PS-31, "HYDRAULIC LINE" .
Condition Voltage
Steering wheel is being turned. 0.5 - 4.5V
Steering wheel is not being turned. 0.4 - 0.8V
MBIB0126E

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

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