2004 INFINITI QX56 fuel

DTC P0461 FUEL LEVEL SENSOR
EC-337
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: August 20072004 QX56
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-337, "
Diagnostic 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-46, "
FUEL PRESSURE RELEASE" .
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-337, "
Diagnostic Procedure" .
Diagnostic ProcedureUBS00H65
1. CHECK DTC WITH COMBINATION METER
Refer to DI-5, "
COMBINATION METERS" .
OK or NG
OK >> GO TO 2.
NG >> Go to DI-22, "
Fuel Level Sensor Unit Inspection" .
2. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Removal and InstallationUBS00H66
FUEL LEVEL SENSOR
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" .
SEF 1 95 Y

EC-338Revision: August 2007
DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUIT
2004 QX56
DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUITPFP:25060
Component DescriptionUBS00H67
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 LogicUBS00H68
NOTE:
If DTC P0462 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
This diagnosis indicates the former, to detect open or short circuit malfunction.
DTC Confirmation ProcedureUBS00H69
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-339, "
Diagnostic 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.
SEF 1 95 Y

DTC P0462, P0463 FUEL LEVEL SENSOR CIRCUIT
EC-339
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: August 20072004 QX56
Diagnostic ProcedureUBS00H6A
1. CHECK DTC WITH COMBINATION METER
Refer to DI-5, "
COMBINATION METERS" .
OK or NG
OK >> GO TO 2.
NG >> Go to DI-22, "
Fuel Level Sensor Unit Inspection" .
2. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Removal and InstallationUBS00H6B
FUEL LEVEL SENSOR
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" .

EC-340Revision: August 2007
DTC P0500 VSS
2004 QX56
DTC P0500 VSSPFP:32702
DescriptionUBS00H6C
NOTE:
If DTC P0500 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
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 LogicUBS00H6D
DTC Confirmation ProcedureUBS00H6E
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-341, "
Diagnostic Procedure" .
If OK, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-II.
4. Warm engine up to normal operating temperature.
5. Maintain the following conditions for at least 60 consecutive sec-
onds.
6. If 1st trip DTC is detected, go to EC-341, "
Diagnostic Procedure"
.
Overall Function CheckUBS00H6F
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.
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
shorted)

Harness or connectors
(The vehicle speed signal circuit is open or
shorted)

Wheel sensor

Combination meter

ABS actuator and electric unit (control unit)
ENG SPEED More than 1,600 rpm
COOLAN TEMP/S More than 70°C (158°F)
B/FUEL SCHDL More than 6.9 msec
Selector lever Except P or N position
PW/ST SIGNAL OFF
SEF 1 96 Y

EC-354Revision: August 2007
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATER
2004 QX56
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATERPFP:22693
DescriptionUBS00H71
SYSTEM DESCRIPTION
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F sensor 1 element at the specified range.
CONSULT-II Reference Value in Data Monitor ModeUBS00H72
Specification data are reference values.
On Board Diagnosis LogicUBS00H73
DTC Confirmation ProcedureUBS00H74
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 between 10.5V and 16V at
idle.
WITH CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and let it idle for at least 10 seconds.
3. If 1st trip DTC is detected, go to EC-358, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Sensor Input Signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
Air fuel ratio (A/F) sensor 1
heater controlAir fuel ratio (A/F) sensor 1
heater
Mass air flow sensor Amount of intake air
MONITOR ITEM CONDITION SPECIFICATION
A/F S1 HTR (B1)
A/F S1 HTR (B2)

Engine: After warming up, idle the engine 0 - 100%
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1031
1031
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
lowThe current amperage in the heated air fuel ratio
(A/F) sensor 1 heater circuit is out of the normal
range.
(An excessively low voltage signal is sent to ECM
through the heated air fuel ratio (A/F) sensor 1
heater.)

Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)

A/F sensor 1 heater P1051
1051
(Bank 2)
P1032
1032
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
highThe current amperage in the heated air fuel ratio
(A/F) sensor 1 heater circuit is out of the normal
range.
(An excessively high voltage signal is sent to ECM
through the heated air fuel ratio (A/F) sensor 1
heater.)

Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)

A/F sensor 1 heater P1052
1052
(Bank 2)
SEF 0 58 Y

DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATER
EC-359
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: August 20072004 QX56
2. CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
2. Turn ignition switch ON.
3. Check voltage between A/F sensor 1 terminal 3 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E5, F14

IPDM E/R harness connector E119

10A fuse

Harness for open or short between A/F sensor 1 and fuse
>> Repair or replace harness or connectors.
4. CHECK A/F SENSOR 1 HEATER OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 2 (bank 1) or 24 (bank 2) and A/F sensor 1 terminal 4.
Refer to Wiring Diagram.
4. Also check harness for short to ground or 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 A/F SENSOR 1 HEATER
Refer to EC-360, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace A/F sensor 1.Voltage: Battery voltage
BBIA0376E
PBIB1683E
Continuity should exist.

EC-360Revision: August 2007
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATER
2004 QX56
6. CHECK INTERMITTENT INCIDENT
Perform EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> Replace A/F sensor 1.
NG >> Repair or replace.
Component InspectionUBS00H77
AIR FUEL RATIO (A/F) SENSOR 1 HEATER
Check resistance between terminals 3 and 4.
Check continuity between terminals 3 and 1, 2, 5, 6, terminals 4 and
1, 2, 5, 6.
If NG, replace the A/F sensor 1.
CAUTION:

Discard any A/F sensor which has been dropped from a
height of more than 0.5 m (19.7 in) onto a hard surface such
as a concrete floor; use a new one.

Before installing new A/F sensor, clean exhaust system
threads using Heated Oxygen Sensor Thread Cleaner tool
J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Removal and Installation UBS00H78
AIR FUEL RATIO (A/F) SENSOR 1
Refer to EM-19, "EXHAUST MANIFOLD AND THREE WAY CATALYST" . Resistance: 2.3 - 4.3Ω at 25°C (77°F)
Continuity should not exist.
PBIB1684E

DTC P1065 ECM POWER SUPPLY
EC-361
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: August 20072004 QX56
DTC P1065 ECM POWER SUPPLYPFP:23710
Component DescriptionUBS00H79
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 LogicUBS00H7A
DTC Confirmation ProcedureUBS00H7B
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-363, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
PBIB11 64 E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1065
1065ECM 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
SEF 0 58 Y