fuel INFINITI QX56 2009 Factory Service Manual

EC-268
< COMPONENT DIAGNOSIS >[VK56DE]
P0461 FUEL LEVEL SENSOR
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-268, "Diagnosis Procedure"
.
WITH GST
NOTE:
Start from step 8, if it is possibl e 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-487, "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-268, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771536
1.CHECK COMBINATION METER FUNCTION
Refer to MWI-5, "METER SYSTEM : System Diagram"
.
OK or NG
OK >> GO TO 2.
NG >> Go to MWI-34, "Component Inspection"
.
2.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "How to Check Terminal"
and GI-38, "Intermittent Incident".
>> INSPECTION END
Revision: December 20092009 QX56

P0462, P0463 FUEL LEVEL SENSOR
EC-269
< COMPONENT DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
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

EC-270
< COMPONENT DIAGNOSIS >[VK56DE]
P0462, P0463 FUEL LEVEL SENSOR
Refer to
GI-35, "How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
Revision: December 20092009 QX56

EC-272
< COMPONENT DIAGNOSIS >[VK56DE]
P0500 VSS
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to
EC-272, "Diagnosis Procedure"
.
Overall Function CheckINFOID:0000000003771544
Use this procedure to check the overall function of the v ehicle speed signal 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 signal in Service $01 with GST. The vehicle speed signal 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-272, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771545
1.CHECK DTC WITH ABS ACTUATOR AN D ELECTRIC UNIT (CONTROL UNIT)
Refer to BRC-24, "CONSULT-III Function (ABS)"
.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK COMBINATION METER FUNCTION
Refer to MWI-5
.
>> INSPECTION END
B/FUEL SCHDL 6.9 - 31.8 msec
Selector lever Except P or N position
PW/ST SIGNAL OFF
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

EC-288
< COMPONENT DIAGNOSIS >[VK56DE]
P0850 PNP SWITCH
P0850 PNP SWITCH
Component DescriptionINFOID:0000000003771570
When the selector lever position is P or N, trans
mission range signal from the TCM is sent to ECM.
On Board Diagnosis LogicINFOID:0000000003771571
DTC Confirmation ProcedureINFOID:0000000003771572
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, 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.
WITH CONSULT-III
1. Turn ignition switch ON.
2. Select “P/N POSI SW” in “DATA MONITOR” mode wit h CONSULT-III. Then check the “P/N POSI SW” sig-
nal under the following conditions.
If NG, go to EC-289, "Diagnosis Procedure"
.
If OK, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-III.
4. Start engine and warm it up to normal operating temperature.
5. Maintain the following conditions for at least 60 consecutive seconds.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to EC-289, "Diagnosis Procedure"
.
Overall Function CheckINFOID:0000000003771573
Use this procedure to check the overall function of t he transmission range signal circuit. During this check, a
1st trip DTC might not be confirmed.
WITH GST
1. Turn ignition switch ON.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0850
0850 Park/neutral position
switch The transmission range signal is not changed in
the process of engine starting and driving.  Harness or connectors
[The transmission range signal circuit is
open or shorted.]
 Combination meter
TCM
Position (Selector lever) Known-good signal
N or P position ON
Except the above position OFF
ENG SPEED 1,000 - 6,375 rpm
COOLAN TEMP/S More than 70 °C (158 °F)
B/FUEL SCHDL 2.0 - 31.8 msec
VHCL SPEED SE More than 64 km/h (40 MPH)
Selector lever Suitable position
Revision: December 20092009 QX56

P1148, P1168 CLOSED LOOP CONTROLEC-295
< COMPONENT DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P1148, P1168 CLOSED LOOP CONTROL
On Board Diagnosis LogicINFOID:0000000003771580
These self-diagnoses have the on
e trip detection logic.
DTC P1148 or P1168 is displayed with another DTC for air fuel ratio (A/F) sensor 1.
Perform the trouble diagnosis for the corresponding DTC.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1148
11 4 8
(Bank 1) Closed loop control
function The closed loop control function for bank 1 does
not operate even when vehicle is driving in the
specified condition.
 Harness or connectors
[The air fuel ratio (A/F) sensor 1 circuit is
open or shorted.]
 Air fuel ratio (A/F) sensor 1
 Air fuel ratio (A/F) sensor 1 heater
P1168
11 6 8
(Bank 2) The closed loop control function for bank 2 does
not operate even when vehicle is driving in the
specified condition.
Revision: December 20092009 QX56

EC-306
< COMPONENT DIAGNOSIS >[VK56DE]
P1421 COLD START CONTROL
P1421 COLD START CONTROL
DescriptionINFOID:0000000003771601
ECM controls ignition timing and engine idle speed when engine is started with prewarming up condition.
This control promotes the activation of three way ca
talyst by heating the catalyst and reduces emissions.
On Board Diagnosis LogicINFOID:0000000003771602
DTC Confirmation ProcedureINFOID:0000000003771603
NOTE:
 If DTC Confirmation Procedure has been previously conducted, 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 DTC P1421 is displayed with other DTC, firs t perform the trouble diagnosis for other DTC.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Select “DATA MONITOR” mode with CONSULT-IIl.
4. Check that the “COOLAN TEMP/S” indication is between 4 °C (39 °F) and 36 °C (97 °F).
If “COOLAN TEMP/S” indication is within t he specified value, go to the following step.
If “COOLANT TEMP/S” indication is out of the s pecified value, cool engine down or warm engine up and
go to step 1.
5. Start engine and let it idle for 5 minutes.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to EC-306, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771604
1.PERFORM IDLE AIR VOLUME LEARNING
Perform EC-18, "Idle Air Volume Learning"
.
Is Idle Air Volume Lear ning carried out successfully?
Ye s o r N o
Ye s > > G O T O 2 .
No >> Follow the instruction of Idle Air Volume Learning.
2.CHECK INTAKE SYSTEM
Check for the cause of intake air volume lacking. Refer to the following.
 Crushed intake air passage
 Intake air passage clogging
OK or NG
OK >> GO TO 3.
NG >> Repair or replace malfunctioning part
3.CHECK FUEL INJECTION SYSTEM FUNCTION
Perform EC-169, "DTC Confirmation Procedure"
in DTC P0171, P0174 FUEL INJECTION SYSTEM FUNC-
TION.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1421
1421 Cold start emission reduction
strategy monitoring ECM does not control ignition timing and engine
idle speed properly when engine is started with
prewarming up condition.  Lack of intake air volume
 Fuel injection system
ECM
Revision: December 20092009 QX56

EC-308
< COMPONENT DIAGNOSIS >[VK56DE]
P1550 BATTERY CURRENT SENSOR
P1550 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000003771605
The power generation voltage variable control enables fuel con-
sumption to be decreased by reducing the engine load which is
caused by the power generation of the generator. The battery cur-
rent sensor (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. Based on the sensor signal, ECM judges whether or not the
power generation voltage variable control is performed. When per-
forming the power generation voltage variable control, ECM calcu-
lates the target power generation voltage based on the sensor
signal. And ECM sends the calculated value as the power genera-
tion command value to IPDM E/R. For the details of the power gen-
eration voltage variable control, refer to
CHG-7, "System
Description".
: Vehicle front
CAUTION:
Do not connect the electrical compon ent or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
On Board Diagn osis LogicINFOID:0000000003771606
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1550 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-285
.
DTC Confirmation ProcedureINFOID:0000000003771607
If DTC Confirmation Procedure has been previously conducted, 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 8V at idle.
1. Start engine and wait at least 10 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-308, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771608
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
BBIA0744E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1550
1550 Battery current sensor circuit
range/performance The output voltage of the battery current
sensor remains within the specified
range while engine is running.  Harness or connectors
(The sensor circuit is open or shorted.)
 Battery current sensor
Revision: December 20092009 QX56

EC-312
< COMPONENT DIAGNOSIS >[VK56DE]
P1551, P1552 BATTERY CURRENT SENSOR
P1551, P1552 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000003771610
The power generation voltage variable control enables fuel con-
sumption to be decreased by reducing the engine load which is
caused by the power generation of the generator. The battery cur-
rent sensor (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. Based on the sensor signal, ECM judges whether or not the
power generation voltage variable control is performed. When per-
forming the power generation voltage variable control, ECM calcu-
lates the target power generation voltage based on the sensor
signal. And ECM sends the calculated value as the power genera-
tion command value to IPDM E/R. For the details of the power gen-
eration voltage variable control, refer to
CHG-7, "System
Description".
: Vehicle front
CAUTION:
Do not connect the electrical compon ent or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
On Board Diagn osis LogicINFOID:0000000003771611
The MIL will not light up for these self-diagnoses.
NOTE:
If DTC P1551 or P1552 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643.
Refer to EC-285, "On Board Diagnosis Logic"
.
DTC Confirmation ProcedureINFOID:0000000003771612
If DTC Confirmation Procedure has been previously conducted, 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 8V with ignition
switch ON
1. Turn ignition switch ON.
2. Wait at least 10 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-312, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771613
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
BBIA0744E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1551
1551 Battery current sensor circuit
low input An excessively low voltage from the sensor
is sent to ECM.
 Harness or connectors
(The sensor circuit is open or shorted.)
 Battery current sensor
P1552
1552 Battery current sensor circuit
high input An excessively high voltage from the sensor
is sent to ECM.
Revision: December 20092009 QX56