engine INFINITI QX56 2007 Factory Service Manual

EC-432
< SERVICE INFORMATION >
DTC P0506 ISC SYSTEM
NG >> Discover air leak location and repair.
2.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 P0507 ISC SYSTEM
EC-433
< SERVICE INFORMATION >
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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

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

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-
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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.

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

EC-444
< SERVICE INFORMATION >
DTC P0605 ECM
DTC P0605 ECM
Component DescriptionINFOID:0000000003531957
The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The ECM controls the engine.
On Board Diagnosis LogicINFOID:0000000003531958
This self-diagnosis has one or two trip detection logic.
FA I L - S A F E M O D E
ECM enters fail-safe mode when the malfunction A is detected.
DTC Confirmation ProcedureINFOID:0000000003531959
Perform PROCEDURE FOR MALFUNCTION A first. If the 1st trip DTC cannot be confirmed, perform
PROCEDURE FOR MALFUNCTION B. If there is no malfunction on PROCEDURE FOR MALFUNCTION
B, perform PROCEDURE FOR MALFUNCTION C.
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.
PROCEDURE FOR MALFUNCTION A
With CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. If 1st trip DTC is detected, go to EC-445, "
Diagnosis Procedure"
With GST
Follow the procedure “With CONSULT-II” above.
PBIB1164E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0605
0605Engine control moduleA) ECM calculation function is malfunctioning.
•ECM B) ECM EEP-ROM system is malfunctioning.
C) ECM self shut-off function is malfunctioning.
Detected items Engine operation condition in fail-safe mode
Malfunction A• ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx.
5 degrees) by the return spring.
• ECM deactivates ASCD operation.
SEF058Y

DTC P0643 SENSOR POWER SUPPLY
EC-447
< SERVICE INFORMATION >
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DTC P0643 SENSOR POWER SUPPLY
On Board Diagnosis LogicINFOID:0000000003531961
This self-diagnosis has the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003531962
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 1 second.
4. If DTC is detected, go to EC-449, "
Diagnosis Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0643
0643Sensor power supply circuit
shortECM detects a voltage of power source
for sensor is excessively low or high.• Harness or connectors
(APP sensor 1 circuit is shorted.)
(PSP sensor circuit is shorted.)
(Battery current sensor circuit is shorted.)
(Refrigerant pressure sensor circuit is short-
ed.)
(EVAP control system pressure sensor circuit
is shorted.)
• Accelerator pedal position sensor
• Power steering pressure sensor
• Refrigerant pressure sensor
• EVAP control system pressure sensor
Engine operation condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF058Y

DTC P0643 SENSOR POWER SUPPLY
EC-449
< SERVICE INFORMATION >
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Diagnosis ProcedureINFOID:0000000003531964
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 APP SENSOR 1 POWER SUPPLY CIRCUIT
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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 sen-
sor)[Ignition switch: ON]Approximately 5V
68 W/LSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
82 B/RSensor ground
(APP sensor 1)[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
83 G/WSensor ground
(APP sensor 2)[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
90 LSensor power supply
(APP sensor 1)[Ignition switch: ON]Approximately 5V
91 W/RSensor power supply
(APP sensor 2)[Ignition switch: ON]Approximately 5V
98 G/RAccelerator pedal position
sensor 2[Ignition switch: ON]
• Engine: Stopped
• Accelerator pedal: Fully released0.25 - 0.50V
[Ignition switch: ON]
• Engine: Stopped
• Accelerator pedal: Fully depressed2.0 - 2.5V
106 BR/WAccelerator pedal position
sensor 1[Ignition switch: ON]
• Engine: Stopped
• Accelerator pedal: Fully released0.5 - 1.0V
[Ignition switch: ON]
• Engine: Stopped
• Accelerator pedal: Fully depressed4.2 - 4.8V
BBIA0354E