2009 INFINITI QX56 battery

P0462, P0463 FUEL LEVEL SENSOR
EC-269
< COMPONENT DIAGNOSIS > [VK56DE]
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P0462, P0463 FUEL LEVEL SENSOR
Component DescriptionINFOID:0000000003771537
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:0000000003771538
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-86
.
 If DTC P0462 or P0463 is displayed with DTC P0607, first perform the trouble diagnosis for DTC
P0607. Refer to EC-284
.
This diagnosis indicates the former, to detect open or short circuit malfunction.
DTC Confirmation ProcedureINFOID:0000000003771539
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm th at battery voltage is more than 11V at ignition
switch ON.
1. Turn ignition switch ON.
2. Wait at least 5 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-269, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771540
1.CHECK COMBINATION METER FUNCTION
Refer to MWI-5
.
OK or NG
OK >> GO TO 2.
NG >> Go to MWI-34, "Component Inspection"
.
2.CHECK INTERMITTENT INCIDENT
BBIA0402E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0462
0462 Fuel level sensor circuit
low input An 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
0463
Fuel level sensor circuit
high input An excessively high voltage from the sensor is
sent to ECM.
Revision: December 20092009 QX56

P0506 ISC SYSTEMEC-273
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P0506 ISC SYSTEM
DescriptionINFOID:0000000003771546
NOTE:
If DTC P0506 is displayed with ot
her DTC, first perform the trouble diagnosis for the other DTC.
The ECM controls the engine idle speed to a specified leve l through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric thrott le control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idli ng 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 t he 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:0000000003771547
DTC Confirmation ProcedureINFOID:0000000003771548
NOTE:
 If DTC Confirmation Procedure has been previously c onducted, always perform the following before con-
ducting the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
 If the target idle speed is ou t of the specified value, perform EC-18, "Idle Air Volume Learning"
,
before conducting DTC Confirmation Procedure. For the target idle speed, refer to the EC-495, "Idle
Speed and Ignition Timing".
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).
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. Start engine and run it for at least 1 minute at idle speed.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-273, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771549
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.
NG >> Discover air leak location and repair.
2.REPLACE ECM
1. Stop engine.
2. Replace ECM.
3. Perform initialization of IVIS(NATS) system and regist ration of all IVIS(NATS) ignition key IDs. Refer to
SEC-6, "ECM RE-COMMUNICATING FUNCT ION : Special Repair Requirement"
.
4. Perform EC-17, "VIN Registration"
.
5. Perform EC-18, "Accelerator Pedal Released Position Learning"
.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0506
0506 Idle speed control system
RPM lower than expected The idle speed is less than the target idle speed
by 100 rpm or more.  Electric throttle control actuator
 Intake air leak
Revision: December 20092009 QX56

P0507 ISC SYSTEMEC-275
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P0507 ISC SYSTEM
DescriptionINFOID:0000000003771550
NOTE:
If DTC P0507 is displayed with ot
her DTC, first perform the trouble diagnosis for the other DTC.
The ECM controls the engine idle speed to a specified leve l through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric thrott le control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idli ng 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 t he 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:0000000003771551
DTC Confirmation ProcedureINFOID:0000000003771552
NOTE:
 If DTC Confirmation Procedure has been previously c onducted, always perform the following before con-
ducting the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
 If the target idle speed is ou t of the specified value, perform EC-18, "Idle Air Volume Learning"
,
before conducting DTC Confirmation Procedure. For the target idle speed, refer to the EC-495, "Idle
Speed and Ignition Timing".
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).
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. Start engine and run it for at least 1 minute at idle speed.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-275, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771553
1.CHECK PCV HOSE CONNECTION
Confirm that PCV hose is connected correctly.
OK or NG
OK >> GO TO 2.
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.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0507
0507 Idle speed control system
RPM higher than expected The idle speed is more than the target idle
speed by 200 rpm or more.  Electric throttle control actuator
 Intake air leak
 PCV system
Revision: December 20092009 QX56

EC-280
< COMPONENT DIAGNOSIS >[VK56DE]
P0603 ECM POWER SUPPLY
P0603 ECM POWER SUPPLY
DescriptionINFOID:0000000003771559
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.
DTC LogicINFOID:0000000005867524
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next test.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON and wait at least 10 seconds.
2. Turn ignition switch OFF and wait at least 5 minutes
3. Turn ignition switch ON and wait at least 10 seconds.
4. Repeat steps 2 and 3 for five more times.
5. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-280, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000003771562
1.CHECK ECM POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
PBIB1164E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0603
0603 ECM power supply cir-
cuit ECM backup RAM system does not function
properly.  Harness or connectors
[ECM power supply (backup) circuit is
open or shorted.]
 Low battery voltage
 Battery disconnected
ECM
Revision: December 20092009 QX56

P0603 ECM POWER SUPPLYEC-281
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3. Check voltage between ECM terminal 121 and ground with
CONSULT-III or tester.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
 IPDM E/R connector E121
 20A fuse
 Harness for open or short between ECM and battery
>> Repair or replace harness or connectors.
3.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "How to Check Terminal"
and GI-38, "Intermittent Incident".
OK or NG
OK >> GO TO 4.
NG >> Repair or replace harness or connectors.
4.PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT-III
1. Turn ignition switch ON.
2. Select “SELF DIAG RESULTS” mode with CONSULT-III.
3. Touch “ERASE”.
4. Perform DTC Confirmation Procedure.
See EC-280, "DTC Logic"
.
5. Is the 1st trip DTC P0603 displayed again?
With GST
1. Turn ignition switch ON.
2. Select Service $04 with GST.
3. Perform DTC Confirmation Procedure.
See EC-280, "DTC Logic"
.
4. Is the 1st trip DTC P0603 displayed again?
Ye s o r N o
Yes >> GO TO 5.
No >> INSPECTION END
5.REPLACE ECM
1. Replace ECM.
2. Perform initialization of IVIS(NATS) system and regist ration of all IVIS(NATS) ignition key IDs. Refer to
SEC-6, "ECM RE-COMMUNICATING FUNCT ION : Special Repair Requirement"
.
3. Perform EC-17, "VIN Registration"
.
4. Perform EC-18, "Accelerator Pedal Released Position Learning"
.
5. Perform EC-18, "Throttle Valve Closed Position Learning"
.
6. Perform EC-18, "Idle Air Volume Learning"
.
>> INSPECTION END
Voltage: Battery voltage
MBIB0026E
Revision: December 20092009 QX56

P0643 SENSOR POWER SUPPLYEC-285
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P0643 SENSOR POWER SUPPLY
On Board Diagnosis LogicINFOID:0000000003771567
This self-diagnosis has the on
e trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003771568
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-285, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771569
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "Ground Inspection"
.
OK or NG
OK >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0643
0643 Sensor power supply circuit
short ECM 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 se nsor 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) b y the return
spring.
BBIA0354E
Revision: December 20092009 QX56

EC-286
< COMPONENT DIAGNOSIS >[VK56DE]
P0643 SENSOR POWER SUPPLY
NG >> Repair or replace ground connections.
2.CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminal 7 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUITS
Check harness for short to power and short to ground, between the following terminals
OK or NG
OK >> GO TO 4.
NG >> Repair short to ground or short to power in harness or connectors.
4.CHECK COMPONENTS
Check the following.
 EVAP control system pressure sensor (Refer to EC-244, "Component Inspection"
.)
 Power steering pressure sensor (Refer to EC-279, "Component Inspection"
.)
 Battery current sensor (Refer to EC-310, "Component Inspection"
.)
 Refrigerant pressure sensor
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning components.
5.CHECK ACCELERATOR PEDAL POSITION SENSOR
Refer to EC-376, "Component Inspection"
.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
BBIA0361E
Voltage: Approximately 5V
JMBIA0601ZZ
ECM terminal Sensor terminal Reference Wiring Diagram
48 EVAP control system pressure sensor terminal 3
EC-432, "Wiring Diagram - ENGINE
CONTROL SYSTEM -"
49Refrigerant pressure sensor terminal 1
Battery current sensor terminal 1
68 Power steering pressure sensor terminal 1
90 APP sensor terminal 7
Revision: December 20092009 QX56

P0850 PNP SWITCHEC-289
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2. Check voltage between ECM terminal 102 (transmission range
signal) and ground under the following conditions.
3. If NG, go to EC-289, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771574
1.CHECK DTC WITH TCM
Refer to TM-30, "OBD-II Diagnostic Trouble Code (DTC)"
.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK STARTING SYSTEM
Turn ignition switch OFF, then turn it to START.
Does starter motor operate?
Ye s o r N o
Yes >> GO TO 3.
No >> Refer to STR-18
.
3.CHECK TRANSMISSION RANGE INPUT SI GNAL CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch OFF.
2. Disconnect A/T assembly harness connector.
3. Disconnect combination meter harness connector.
4. Check harness continuity between A/T assembly terminal 9 and combination meter terminal 8. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors F14, E5
 Harness connectors E152, M31
 Harness for open or short between A/T assembly and combination meter
>> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK TRANSMISSION RANGE INPUT SI GNAL CIRCUIT FOR OPEN AND SHORT-II
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 102 and combination meter terminal 7. Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
Condition (Gear position) Voltage (Known-good data)
P or N position Approx. 0
Except the above position BATTERY VOLTAGE
(11 - 14V)
MBIB0043E
Continuity should exist.
Continuity should exist.
Revision: December 20092009 QX56