2007 INFINITI QX56 power steering

EC-104
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
5 L/B Throttle control motor (Open)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully depressed0 - 14V
6GRHeated oxygen sensor 2 heat-
er (bank 1)[Engine is running]
• Engine speed: 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: Above 3,600 rpmBATTERY VOLTAGE
(11 - 14V)
10 WIntake valve timing control so-
lenoid valve (bank 1)[Engine is running]
•Warm-up condition
• Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
•Warm-up condition
• Engine speed: 2,000rpm7 - 12V
11 L GIntake valve timing control so-
lenoid valve (bank 2)[Engine is running]
•Warm-up condition
• Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
•Warm-up condition
• Engine speed: 2,000rpm7 - 12V
12 RPower steering pressure sen-
sor[Engine is running]
• Steering wheel: Being turned0.5 - 4.5V
[Engine is running]
• Steering wheel: Not being turned0.4 - 0.8V TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
PBIB1105E
PBIB1790E
PBIB1790E

EC-112
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
*: The following emission-related diagnostic information is cleared when the ECM memory is erased.
• Diagnostic trouble codes
• 1st trip diagnostic trouble codes
• Freeze frame data
• 1st trip freeze frame data
• System readiness test (SRT) codes
•Test values
ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
WORK
SUP-
PORTSELF-DIAGNOSTIC
RESULTS
DATA
MONI-
TORDATA
MONI-
TOR
(SPEC)ACTIVE
TESTDTC & SRT
CONFIRMATION
DTC*1FREEZE
FRAME
DATA*2SRT
STATUSDTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS)××××
Camshaft position sensor (PHASE)××××
Mass air flow sensor×××
Engine coolant temperature sensor×××××
Air fuel ratio (A/F) sensor 1×××××
Heated oxygen sensor 2×××××
Wheel sensor××××
Accelerator pedal position sensor×××
Throttle position sensor××××
Fuel tank temperature sensor××××
EVAP control system pressure sen-
sor×××
Intake air temperature sensor××××
Knock sensor×
Refrigerant pressure sensor××
Closed throttle position switch (ac-
celerator pedal position sensor sig-
nal)××
Air conditioner switch××
Park/neutral position (PNP) switch×××
Stop lamp switch×××
Power steering pressure sensor×××
Battery voltage××
Load signal××
Intake valve timing control position
sensor×××
Fuel level sensor×××
Battery current sensor×××
ICC steering switch×××
ASCD steering switch×××
ICC brake switch×××
ASCD brake switch×××

EC-116
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
FUEL T/TMP SE
[°C] or [°F]ו The fuel temperature (determined by the
signal voltage of the fuel tank tempera-
ture sensor) is displayed.
INT/A TEMP SE
[°C] or [°F]×ו The intake air temperature (determined
by the signal voltage of the intake air
temperature sensor) is indicated.
EVAP SYS PRES
[V]ו The signal voltage of EVAP control sys-
tem pressure sensor is displayed.
FUEL LEVEL SE [V]ו The signal voltage of the fuel level sen-
sor is displayed.
START SIGNAL
[ON/OFF]×ו Indicates start signal status [ON/OFF]
computed by the ECM according to the
signals of engine speed and battery volt-
age.• After starting the engine, [OFF] is dis-
played regardless of the starter signal.
CLSD THL POS
[ON/OFF]×ו Indicates idle position [ON/OFF] comput-
ed by ECM according to the accelerator
pedal position sensor signal.
AIR COND SIG
[ON/OFF]×ו Indicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
P/N POSI SW
[ON/OFF]×ו Indicates [ON/OFF] condition from the
park/neutral position (PNP) switch sig-
nal.
PW/ST SIGNAL
[ON/OFF]×ו [ON/OFF] condition of the power steering
system (determined by the signal voltage
of the power steering pressure sensor
signal) is indicated.
LOAD SIGNAL [ON/
OFF]×ו Indicates [ON/OFF] condition from the
electrical load signal.
ON: Rear window defogger switch is ON
and/or lighting switch is in 2nd position.
OFF: Both rear window defogger switch
and lighting switch are OFF.
IGNITION SW
[ON/OFF]ו Indicates [ON/OFF] condition from igni-
tion switch signal.
HEATER FAN SW
[ON/OFF]ו Indicates [ON/OFF] condition from heat-
er fan switch signal.
BRAKE SW
[ON/OFF]ו Indicates [ON/OFF] condition from the
stop lamp switch signal.
INJ PULSE-B1
[msec]×
• Indicates the actual fuel injection pulse
width compensated by ECM according to
the input signals.• When the engine is stopped, a certain
computed value is indicated.
INJ PULSE-B2
[msec]
IGN TIMING [BT-
DC]ו Indicates the ignition timing computed by
ECM according to the input signals.• When the engine is stopped, a certain
value is indicated.
CAL/LD VALUE [%]• “Calculated load value” indicates the val-
ue of the current air flow divided by peak
air flow.
MASS AIRFLOW
[g·m/s]• Indicates the mass air flow computed by
ECM according to the signal voltage of
the mass air flow sensor. Monitored item
[Unit]ECM IN-
PUT SIG-
NALSMAIN
SIGNALSDescription Remarks

EC-134
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
12.CHECK A/F SENSOR 1 FUNCTION
Perform all DTC Confirmation Procedure related with A/F sensor 1.
• For DTC P0130, P0150, refer to EC-225, "
DTC Confirmation Procedure" .
• For DTC P0131, P0151, refer to EC-234, "
DTC Confirmation Procedure" .
• For DTC P0132, P0132, refer to EC-242, "
DTC Confirmation Procedure" .
• For DTC P0133, P0153, refer to EC-250, "
DTC Confirmation Procedure" .
• For DTC P2A00, P2A03, refer to EC-588, "
DTC Confirmation Procedure" .
OK or NG
OK >> GO TO 15.
NG >> GO TO 13.
13.CHECK A/F SENSOR 1 CIRCUIT
Perform Diagnostic Procedure according to corresponding DTC.
>> GO TO 14.
14.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “DATA MONITOR (SPEC)” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >>INSPECTION END
NG >> GO TO 15.
15.DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR
1. Stop the engine.
2. Disconnect ECM harness connector. Check pin terminal and connector for damage, and then reconnect it.
>> GO TO 16.
16.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “DATA MONITOR (SPEC)” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >>INSPECTION END
NG >> Detect malfunctioning part according to EC-90, "
Symptom Matrix Chart" .
17.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “DATA MONITOR (SPEC)” mode, and
make sure that the indication is within the SP value.
OK or NG
OK >>INSPECTION END
NG (More than the SP value)>>GO TO 18.
NG (Less than the SP value)>>GO TO 25.
18.DETECT MALFUNCTIONING PART
1. Check for the cause of large engine friction. Refer to the following.
- Engine oil level is too high
- Engine oil viscosity
- Belt tension of power steering, alternator, A/C compressor, etc. is excessive
- Noise from engine
PBIB2332E

DTC P0506 ISC SYSTEM
EC-431
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
DTC P0506 ISC SYSTEM
DescriptionINFOID:0000000003531936
NOTE:
If DTC P0506 is displayed with other DTC, first perform the trouble diagnosis for the other DTC.
The ECM controls the engine idle speed to a specified level through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric throttle control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idling speed. The crankshaft position sensor (POS) detects
the actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration, and engine load (air conditioner, power steering and cooling fan
operation, etc.).
On Board Diagnosis LogicINFOID:0000000003531937
DTC Confirmation ProcedureINFOID:0000000003531938
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.
•If the target idle speed is out of the specified value, perform EC-78, "
Idle Air Volume Learning" ,
before conducting DTC Confirmation Procedure. For the target idle speed, refer to the EC-645
.
TESTING CONDITION:
•Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
•Always perform the test at a temperature above −10°C (14°F).
WITH CONSULT-II
1. Open engine hood.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON again and select “DATA MONITOR”
mode with CONSULT-II.
5. Start engine and run it for at least 1 minute at idle speed.
6. If 1st trip DTC is detected, go to EC-431, "
Diagnosis Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnosis ProcedureINFOID:0000000003531939
1.CHECK INTAKE AIR LEAK
1. Start engine and let it idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0506
0506Idle speed control system
RPM lower than expectedThe idle speed is less than the target idle speed
by 100 rpm or more.• Electric throttle control actuator
• Intake air leak
SEF174Y

DTC P0507 ISC SYSTEM
EC-433
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
DTC P0507 ISC SYSTEM
DescriptionINFOID:0000000003531940
NOTE:
If DTC P0507 is displayed with other DTC, first perform the trouble diagnosis for the other DTC.
The ECM controls the engine idle speed to a specified level through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric throttle control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idling speed. The crankshaft position sensor (POS) detects
the actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration, and engine load (air conditioner, power steering and cooling fan
operation, etc.).
On Board Diagnosis LogicINFOID:0000000003531941
DTC Confirmation ProcedureINFOID:0000000003531942
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.
•If the target idle speed is out of the specified value, perform EC-78, "
Idle Air Volume Learning" ,
before conducting DTC Confirmation Procedure. For the target idle speed, refer to the EC-645
.
TESTING CONDITION:
•Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
•Always perform the test at a temperature above −10°C (14°F).
WITH CONSULT-II
1. Open engine hood.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON again and select “DATA MONITOR”
mode with CONSULT-II.
5. Start engine and run it for at least 1 minute at idle speed.
6. If 1st trip DTC is detected, go to EC-433, "
Diagnosis Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnosis ProcedureINFOID:0000000003531943
1.CHECK PCV HOSE CONNECTION
Confirm that PCV hose is connected correctly.
OK or NG
OK >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0507
0507Idle speed control system
RPM higher than expectedThe idle speed is more than the target idle
speed by 200 rpm or more.• Electric throttle control actuator
• Intake air leak
• PCV system
SEF174Y

DTC P0550 PSP SENSOR
EC-435
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
DTC P0550 PSP SENSOR
Component DescriptionINFOID:0000000003531944
Power steering pressure (PSP) sensor (1) 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 ModeINFOID:0000000003531945
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531946
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P0550 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to
EC-447
.
DTC Confirmation ProcedureINFOID:0000000003531947
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-437, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
BBIA0741E
MONITOR ITEM CONDITION SPECIFICATION
PW/ST SIGNAL• Engine: After warming up, idle the
engineSteering wheel: Not being turned
(Forward direction)OFF
Steering wheel: Being 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
SEF058Y

DTC P0550 PSP SENSOR
EC-437
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
Diagnosis ProcedureINFOID:0000000003531949
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-143, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK PSP SENSOR POWER SUPPLY CIRCUIT
1. Disconnect power steering pressure (PSP) sensor (1) harness
connector.
2. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
12 RPower steering pressure
sensor[Engine is running]
• Steering wheel: Being turned.0.5 - 4.5V
[Engine is running]
• Steering wheel: 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
BBIA0741E