2007 INFINITI QX56 DTC

EC-426
< SERVICE INFORMATION >
DTC P0461 FUEL LEVEL SENSOR
6. Select “FUEL LEVEL SE” in “DATA MONITOR” mode with CON-
SULT-II.
7. Check “FUEL LEVEL SE” output voltage and note it.
8. Select “FUEL PUMP” in “ACTIVE TEST” mode with CONSULT-
II.
9. Touch “ON” and drain fuel approximately 30 (7-7/8 US gal, 6-
5/8 Imp gal) and stop it.
10. Check “FUEL LEVEL SE” output voltage and note it.
11. Fill fuel into the fuel tank for 30 (7-7/8 US gal, 6-5/8 Imp gal).
12. Check “FUEL LEVEL SE” output voltage and note it.
13. Confirm whether the voltage changes more than 0.03V during
step 7 to 10 and 10 to 12.
If NG, go to EC-426, "
Diagnosis Procedure" .
WITH GST
NOTE:
Start from step 8, if it is possible to confirm that the fuel cannot be drained by 30 (7-7/8 US gal, 6-5/8
Imp gal) in advance.
1. Prepare a fuel container and a spare hose.
2. Release fuel pressure from fuel line. Refer to EC-80, "
Fuel Pressure Check" .
3. Remove the fuel feed hose on the fuel level sensor unit.
4. Connect a spare fuel hose where the fuel feed hose was removed.
5. Turn ignition switch ON.
6. Drain fuel by 30 (7-7/8 US gal, 6-5/8 Imp gal) from the fuel tank using proper equipment.
7. Confirm that the fuel gauge indication varies.
8. Fill fuel into the fuel tank for 30 (7-7/8 US gal, 6-5/8 Imp gal).
9. Confirm that the fuel gauge indication varies.
10. If NG, go to EC-426, "
Diagnosis Procedure" .
Diagnosis ProcedureINFOID:0000000003531924
1.CHECK COMBINATION METER FUNCTION
Refer to DI-5
.
OK or NG
OK >> GO TO 2.
NG >> Go to DI-18, "
Fuel Level Sensor Unit Inspection" .
2.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Removal and InstallationINFOID:0000000003531925
FUEL LEVEL SENSOR
Refer to FL-5.
SEF195Y

DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUIT
EC-427
< SERVICE INFORMATION >
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DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUIT
Component DescriptionINFOID:0000000003531926
The fuel level sensor is mounted in the fuel level sensor unit. The
sensor detects a fuel level in the fuel tank and transmits a signal to
the combination meter. The combination meter sends the fuel level
sensor signal to the ECM through CAN communication line.
It consists of two parts, one is mechanical float and the other is vari-
able resistor. Fuel level sensor output voltage changes depending on
the movement of the fuel mechanical float.
On Board Diagnosis LogicINFOID:0000000003531927
NOTE:
•If DTC P0462 or P0463 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for
DTC U1000, U1001. Refer to EC-145
.
•If DTC P0462 or P0463 is displayed with DTC U1010, first perform the trouble diagnosis for DTC
U1010. Refer to EC-147
.
This diagnosis indicates the former, to detect open or short circuit malfunction.
DTC Confirmation ProcedureINFOID:0000000003531928
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 11V at ignition
switch ON.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 5 seconds.
4. If 1st trip DTC is detected, go to EC-428, "
Diagnosis Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
BBIA0402E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0462
0462Fuel level sensor circuit
low inputAn excessively low voltage from the sensor is
sent to ECM.• Harness or connectors
(The CAN communication line is open or
shorted)
• Harness or connectors
(The sensor circuit is open or shorted)
• Combination meter
• Fuel level sensor P0463
0463Fuel level sensor circuit
high inputAn excessively high voltage from the sensor is
sent to ECM.
SEF195Y

EC-428
< SERVICE INFORMATION >
DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUIT
Diagnosis Procedure
INFOID:0000000003531929
1.CHECK COMBINATION METER FUNCTION
Refer to DI-5
.
OK or NG
OK >> GO TO 2.
NG >> Go to DI-18, "
Fuel Level Sensor Unit Inspection".
2.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Removal and InstallationINFOID:0000000003531930
FUEL LEVEL SENSOR
Refer to FL-5 .

DTC P0500 VSS
EC-429
< SERVICE INFORMATION >
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DTC P0500 VSS
DescriptionINFOID:0000000003531931
NOTE:
•If DTC P0500 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-145
.
•If DTC P0500 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010. Refer
to EC-147
.
The vehicle speed signal is sent to the combination meter from the “ABS actuator and electric unit (control
unit)” by CAN communication line. The c combination meter then sends a signal to the ECM by CAN commu-
nication line.
On Board Diagnosis LogicINFOID:0000000003531932
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureINFOID:0000000003531933
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.
TESTING CONDITION:
Steps 1 and 2 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. Start engine (VDC switch OFF).
2. Read “VHCL SPEED SE” in “DATA MONITOR” mode with CONSULT-II. The vehicle speed on CONSULT-
II should exceed 10 km/h (6 MPH) when rotating wheels with suitable gear position.
If NG, go to EC-430, "
Diagnosis Procedure".
If OK, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-II.
4. Warm engine up to normal operating temperature.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0500
0500Vehicle speed sensorThe almost 0 km/h (0 MPH) signal from
vehicle speed sensor is sent to ECM even
when vehicle is being driven.• Harness or connectors
(The CAN communication line is open or short-
ed)
• Harness or connectors
(The vehicle speed signal circuit is open or
shorted)
• Wheel sensor
• Combination meter
• ABS actuator and electric unit (control unit)
Detected items Engine operating condition in fail-safe mode
Vehicle speed sensorWhen the fail-safe system for vehicle speed sensor is activated, the cooling fan operates (High) while
engine is running.

EC-430
< SERVICE INFORMATION >
DTC P0500 VSS
5. Maintain the following conditions for at least 60 consecutive sec-
onds.
6. If 1st trip DTC is detected, go to EC-430, "
Diagnosis Procedure".
Overall Function CheckINFOID:0000000003531934
Use this procedure to check the overall function of the vehicle speed sensor circuit. During this check, a 1st
trip DTC might not be confirmed.
WITH GST
1. Lift up drive wheels.
2. Start engine.
3. Read vehicle speed sensor signal in Service $01 with GST.
The vehicle speed sensor on GST should be able to exceed 10 km/h (6 MPH) when rotating wheels with
suitable gear position.
4. If NG, go to EC-430, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000003531935
1.CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Refer to BRC-11
.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK COMBINATION METER FUNCTION
Refer to DI-5
.
>>INSPECTION END
ENG SPEED 1,600 - 6,000 rpm
COOLAN TEMP/S More than 70°C (158°F)
B/FUEL SCHDL 6.9 - 31.8 msec
Selector lever Except P or N position
PW/ST SIGNAL OFF
SEF196Y

DTC P0506 ISC SYSTEM
EC-431
< SERVICE INFORMATION >
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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

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