2007 INFINITI QX56 DTC

EC-434
< SERVICE INFORMATION >
DTC P0507 ISC SYSTEM
NG >> Repair or replace.
2.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 3.
NG >> Discover air leak location and repair.
3.REPLACE ECM
1. Stop engine.
2. Replace ECM.
3. Perform initialization of IVIS(NATS) system and registration of all IVIS(NATS) ignition key IDs. Refer to
BL-117, "
ECM Re-communicating Function".
4. Perform EC-77, "
VIN Registration" .
5. Perform EC-77, "
Accelerator Pedal Released Position Learning" .
6. Perform EC-77, "
Throttle Valve Closed Position Learning" .
7. Perform EC-78, "
Idle Air Volume Learning" .
>>INSPECTION END

DTC P0550 PSP SENSOR
EC-435
< SERVICE INFORMATION >
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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

EC-436
< SERVICE INFORMATION >
DTC P0550 PSP SENSOR
Wiring Diagram
INFOID:0000000003531948
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.
BBWA2097E

DTC P0550 PSP SENSOR
EC-437
< SERVICE INFORMATION >
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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

EC-438
< SERVICE INFORMATION >
DTC P0550 PSP SENSOR
3. Check voltage between PSP sensor terminal 1 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connectors.
3.CHECK PSP SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between PSP sensor terminal 3 and ECM terminal 67.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK PSP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 12 and PSP sensor terminal 2.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK PSP SENSOR
Refer to EC-438, "
Component Inspection".
OK or NG
OK >> GO TO 6.
NG >> Replace PSP sensor.
6.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Component InspectionINFOID:0000000003531950
POWER STEERING PRESSURE SENSOR
1. Reconnect all harness connectors disconnected.
2. Start engine and let it idle.Voltage: Approximately 5V
PBIB0188E
Continuity should exist.
Continuity should exist.

DTC P0550 PSP SENSOR
EC-439
< SERVICE INFORMATION >
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3. Check voltage between ECM terminal 12 and ground under the
following conditions.
Removal and InstallationINFOID:0000000003531951
POWER STEERING PRESSURE SENSOR
Refer to PS-23.
Condition Voltage
Steering wheel: Being turned. 0.5 - 4.5V
Steering wheel: Not being turned. 0.4 - 0.8V
MBIB0126E

EC-440
< SERVICE INFORMATION >
DTC P0603 ECM POWER SUPPLY
DTC P0603 ECM POWER SUPPLY
Component DescriptionINFOID:0000000003531952
Battery voltage is supplied to the ECM even when the ignition switch
is turned OFF for the ECM memory function of the DTC memory, the
air-fuel ratio feedback compensation value memory, the idle air vol-
ume learning value memory, etc.
On Board Diagnosis LogicINFOID:0000000003531953
DTC Confirmation ProcedureINFOID:0000000003531954
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 and wait at least 1 second.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 1 second.
4. Turn ignition switch OFF, wait at least 10 seconds and then turn
ON.
5. Repeat steps 3 and 4 for 4 times.
6. If 1st trip DTC is detected, go to EC-442, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
PBIB1164E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0603
0603ECM power supply circuitECM back-up RAM system does not function
properly.• Harness or connectors
[ECM power supply (back-up) circuit is
open or shorted.]
•ECM
SEF058Y

DTC P0603 ECM POWER SUPPLY
EC-441
< SERVICE INFORMATION >
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Wiring DiagramINFOID:0000000003531955
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.
BBWA2098E