check engine INFINITI QX56 2011 Factory Service Manual

EC-468
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2122, P2123 APP SENSOR
P2122, P2123 APP SENSOR
DTC LogicINFOID:0000000006217972
DTC DETECTION LOGIC
NOTE:
If DTC P2122 or P2123 is displayed with DTC P
0643, perform the trouble diagnosis for DTC P0643.
Refer to EC-381, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is 8 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for 1 second.
2. Check DTC.
Is DTC detected?
YES >> Go to EC-468, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217973
1.CHECK ACCELERATOR PEDAL POSITION SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check the voltage between APP sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between ECM and APP sensor
 Loose or poor connection for each connector and harness
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2122 APP SEN 1/CIRC
(Accelerator pedal position
sensor 1 circuit low input) An excessively low voltage from the APP
sensor 1 is sent to ECM.
 Harness or connectors
(APP sensor 1 circuit is open or shorted.)
 Accelerator pedal position sensor (APP sensor 1)
P2123 APP SEN 1/CIRC
(Accelerator pedal position
sensor 1 circuit high input) An excessively high voltage from the APP
sensor 1 is sent to ECM.
APP sensor
Ground Voltage (V)
Connector Terminal
E110
(Without ICC) 2
Ground Approx. 5
E67
(With ICC) 12
Revision: 2010 May2011 QX56

P2127, P2128 APP SENSOREC-471
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P2127, P2128 APP SENSOR
DTC LogicINFOID:0000000006217975
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is 8 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for 1 second.
2. Check DTC.
Is DTC detected?
YES >> Go to EC-471, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217976
1.CHECK ACCELERATOR PEDAL POSITION SENSOR 2 POWER SUPPLY CIRCUIT-I
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check the voltage between APP sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2127 APP SEN 2/CIRC
(Accelerator pedal position
sensor 2 circuit low input) An excessively low voltage from
the APP sensor 2 is sent to ECM.  Harness or connectors
(Accelerator pedal position sensor 2 circuit is open or
shorted.)
(Battery current sensor circuit is shorted.)
[Camshaft position sensor (bank 1) circuit is shorted.]
(Crankshaft position sensor circuit is shorted.)
(Refrigerant pressure sensor circuit is shorted.)
(EVAP control system pres sure sensor circuit is
shorted.)
 Accelerator pedal position sensor (APP sensor 2)
 Battery current sensor
 Camshaft position sensor (bank 1)
 Crankshaft position sensor
 Refrigerant pressure sensor
 EVAP control system pressure sensor
P2128
APP SEN 2/CIRC
(Accelerator pedal position
sensor 2 circuit high input) An excessively high voltage from
the APP sensor 2 is sent to ECM.
APP sensor
Ground Voltage (V)
Connector Terminal
E110
(Without ICC) 1
Ground Approx. 5
E67
(With ICC) 9
Revision: 2010 May2011 QX56

P2135 TP SENSOREC-475
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P2135 TP SENSOR
DTC LogicINFOID:0000000006217978
DTC DETECTION LOGIC
NOTE:
If DTC P2135 is displayed with DTC P0643, perfo
rm the trouble diagnosis for DTC P0643. Refer to EC-
381, "DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is 8 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for 1 second.
2. Check DTC.
Is DTC detected?
YES >> Go to EC-475, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217979
1.CHECK THROTTLE POSITION SEN SOR POWER SUPPLY CIRCUIT-I
1. Disconnect electric throttle c ontrol actuator harness connector.
2. Turn ignition switch ON.
3. Check the voltage between electric throttle control actuator harness connector and ground.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
2.CHECK THROTTLE POSITI ON SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between electric throttle control actuator harness connector and ECM harness con-
nector.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2135 TP SENSOR-B1
(Throttle position sensor circuit
range/performance) Rationally incorrect voltage is sent to
ECM compared with the signals from
TP sensor 1 and TP sensor 2.  Harness or connector
(TP sensor 1 or 2 circuit is open or shorted.)
 Electric throttle control actuator
(TP sensor 1 or 2)
Electric throttle control actuator Ground Voltage (V)
Connector Terminal
F66 2 Ground Approx. 5
Revision: 2010 May2011 QX56

EC-478
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2138 APP SENSOR
P2138 APP SENSOR
DTC LogicINFOID:0000000006217981
DTC DETECTION LOGIC
NOTE:
If DTC P2138 is displayed with DTC P0643, first pe
rform the trouble diagnosis for DTC P0643. Refer to
EC-381, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is 8 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for 1 second.
2. Check DTC.
Is DTC detected?
YES >> Go to EC-478, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217982
1.CHECK ACCELERATOR PEDAL POSITION SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check the voltage between APP sensor harness connector and ground.
Is the inspection result normal?
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2138 APP SENSOR
(Accelerator pedal position
sensor circuit range/perfor-
mance) Rationally incorrect voltage is
sent to ECM compared with
the signals from APP sensor 1
and APP sensor 2.  Harness or connectors
(APP sensor 1 or 2 circuit is open or shorted.)
[CKP sensor circuit is shorted.]
[CMP sensor (bank 1) circuit is shorted.]
(Battery current sensor circuit is shorted.)
(Refrigerant pressure sensor circuit is shorted.)
(EVAP control system pressure sensor circuit is short-
ed.)
 Accelerator pedal position sensor (APP sensor 1 or 2)
 Crankshaft position sensor
 Camshaft position sensor (bank 1)
 Refrigerant pressure sensor
 Battery current sensor
 EVAP control system pressure sensor
APP sensor Ground Voltage (V)
Connector Terminal
E110
(Without ICC) 2
Ground Approx. 5
E67
(With ICC) 12
Revision: 2010 May2011 QX56

P2539, P2541, P2542 LOW FUEL PRESSURE SENSOR
EC-483
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P2539, P2541, P2542 LOW
FUEL PRESSURE SENSOR
DTC LogicINFOID:0000000006288355
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for at least 60 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-483, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288356
1.CHECK LOW FUEL PRESSURE SENSOR POWER SUPPLY-I
1. Turn ignition switch OFF.
2. Disconnect low fuel pressure sensor connector.
3. Turn ignition switch ON.
4. Check the voltage between low fuel pressure sensor harness connector terminals.
Inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK LOW FUEL PRESSURE SENSOR POWER SUPPLY-II
Check the voltage between low fuel pressure sensor harness connector and the ground.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2539 LOW FUEL PRES SEN
(Low fuel pressure sensor
circuit low input and high in-
put) Signal voltage from the low fuel pressure
sensor remains at more than 4.84 V / less
than 0.3 V for 5 seconds or more.  Harness or connectors
(Low fuel pressure sensor circuit is open
or shorted.)
(Power steering pressure sensor circuit is
open or shorted.)
(Cooling fan speed sensor circuit is open
or shorted.)
(FRP sensor circuit is open or shorted.)
 Low fuel pressure sensor
 Power steering pressure sensor
 Cooling fan speed sensor
 FRP sensor
P2541
LOW FUEL PRES SEN
(Low fuel pressure sensor
circuit low input) Signal voltage from the low fuel pressure
sensor remains at less than 0.49 V for 5 sec-
onds or more.
P2542 LOW FUEL PRES SEN
(Low fuel pressure sensor
circuit high input) Signal voltage from the low fuel pressure
sensor remains at more than 4.1 V for 5 sec-
onds or more.
Low fuel pressure sensor
Vo l ta g e
(Approx.)
Connector +
−
terminal
F25 3 1 5 V
Revision: 2010 May2011 QX56

P2539, P2541, P2542 LOW FUEL PRESSURE SENSOR
EC-485
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NO >> Repair or replace error-detected parts.
6.CHECK LOW FUEL PRESSURE SENSOR SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between low fuel pressu re sensor harness connector and ECM harness connector.
4. Also check harness for short to ground and to power.
Is inspection result normal?
YES >> GO TO 7.
NO >> Repair or replace error-detected parts.
7.CHECK LOW FUEL PRESSURE SENSOR
Refer to EC-485, "
Component Inspection".
Is inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
NO >> Replace low fuel pressure sensor.
Component InspectionINFOID:0000000006289706
1.CHECK LOW FUEL PRESSURE SENSOR
WITH CONSULT-III
1. Turn ignition switch OFF.
2. Reconnect harness connector disconnected.
3. Start the engine.
4. Select “DATA MONITOR” mode with CONSULT-III.
5. Check that the “L/FUEL PRES SEN V” value.
WITHOUT CONSULT-III
1. Turn ignition switch OFF.
2. Reconnect harness connector disconnected.
3. Start the engine.
4. Check low fuel pressure sensor signal voltage.
+ −
Continuity
Low fuel pressure sensor ECM
Connector Terminal Connector Terminal F25 2 F111 23 Existed
Data monitor item Condition Va l u e
(Approx.)
L/FUEL PRES SEN V Engine speed: idle
3,000 –3,300 mV
Engine speed: 3,000 rpm (no load)
Revision: 2010 May2011 QX56

P2A00, P2A03 A/F SENSOR 1EC-487
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P2A00, P2A03 A/F SENSOR 1
DTC LogicINFOID:0000000006217987
DTC DETECTION LOGIC
To judge the malfunction, the A/F signal computed by ECM fr
om the A/F sensor 1 signal is monitored so it will
not shift to LEAN side or RICH side.
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Clear the mixture ratio self-learning value. Refer to EC-152, "
Work Procedure".
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Start engine and keep the engine speed between 3,500 and 4,000 rpm for 1 minute under no load.
6. Let engine idle for 1 minute.
7. Keep engine speed between 2,500 and 3,000 rpm for 20 minutes.
8. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-487, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217988
1.RETIGHTEN A/F SENSOR 1
Loosen and retighten the A/F sensor 1. Refer to EX-5, "
Exploded View".
>> GO TO 2.
2.CHECK A/F SENSOR 1 CONNECTOR
1. Disconnect A/F sensor 1 harness connector.
2. Check that water is not inside connectors.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace harness connector.
3.CHECK FOR INTAKE AIR LEAKAGE
1. Reconnect A/F sensor 1 harness connector.
2. Start engine and run it at idle.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2A00 A/F SENSOR1 (B1)
(Air fuel ratio (A/F) sensor 1 (bank 1)
circuit range/performance)  The output voltage computed by ECM from
the A/F sensor 1 signal shifts to the lean side
for a specified period.
 The A/F signal computed by ECM from the
A/F sensor 1 signal shifts to the rich side for
a specified period.  A/F sensor 1
 A/F sensor 1 heater
 Fuel pressure
 Fuel injector
 Intake air leaks
P2A03 A/F SENSOR1 (B2)
(Air fuel ratio (A/F) sensor 1 (bank 2)
circuit range/performance)
Revision: 2010 May2011 QX56

EC-488
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2A00, P2A03 A/F SENSOR 1
3. Listen for an intake air leakage after the mass air flow sensor.
Is intake air leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 4.
4.CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
1. Clear the mixture ratio self-learning value. Refer to EC-152, "
Work Procedure".
2. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P 0175 detected? Is it difficult to start engine?
YES >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-264, "Diagnosis
Procedure" or EC-268, "Diagnosis Procedure".
NO >> GO TO 5.
5.CHECK AIR FUEL RATIO SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
2. Turn ignition switch ON.
3. Check the voltage between A/F sensor 1 harness connector and ground.
Is the inspection result normal?
YES >> GO TO 6.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
6.CHECK A/F SENSOR 1 INPUT SIGN AL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.
5. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
7.CHECK A/F SENSOR 1 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
DTCA/F sensor 1
Ground Voltage
Bank Connector Terminal
P2A00 1 F67 4 Ground 3.0 V
P2A03 2 F68 4
DTC A/F sensor 1 ECM
Continuity
Bank Connector Terminal Connector Terminal
P2A00 1 F67 3 F11088
Existed
P2A03 2 F68 3 78
DTC A/F sensor 1 ECM
Ground Continuity
Bank Connector Terminal Connector Terminal
P2A00 1 F67 3 F11088
Ground Not existed
P2A03 2 F68 3 78
Revision: 2010 May2011 QX56

ELECTRICALLY-CONTROLLED COOLING FAN COUPLINGEC-495
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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ELECTRICALLY-CONTROLLED COOLING FAN COUPLING
Component Function CheckINFOID:0000000006217997
1.CHECK COOLING FAN FUNCTION
WITH CONSULT-III
1. Start the engine.
2. Perform “FAN DUTY CONTROL” in “ACTIVE TEST” mode with CONSULT-III.
3. Check that cooling fan speed varies according to the percentage.
NOTE:
Speed changes gradually as the percentage changes.
WITHOUT CONSULT-III
1. Start the engine and warm up the engine until engine coolant temperature reaches at least 98°C (209 °F).
2. Check that cooling fan speed increase.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Proceed to EC-495, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000006217998
1.CHECK DRIVE BELT
1. Turn ignition switch OFF.
2. Check that the drive belt is not broken.
Is inspection result normal?
YES >> GO TO 2.
NO >> Replace drive belt.
2.CHECK ELECTRICALLY-CONTROLLED COOLING FAN COUPLING POWER SUPPLY
1. Disconnect electrically-controlled c ooling fan coupling harness connector.
2. Turn ignition switch ON.
3. Check the voltage between electrically-controll ed cooling fan coupling harness connector and ground.
Is inspection result normal?
YES >> GO TO 3.
NO >> Perform trouble diagnosis for power supply circuit.
3.CHECK ELECTRICALLY-CONTROLLED COOLING FAN COUPLING GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check the continuity between electrically-cont rolled cooling fan coupling harness connector and ground.
Is inspection result normal?
YES >> GO TO 4.
NO >> Repair or replace error-detected parts.
4.CHECK ELECTRICALLY-CONTROLLED COOLING FAN COUPLING CONTROL SIGNAL
WITH CONSULT-III
+ −Vo l ta g e
(Approx.)
Electrically-controlled cooling fan coupling
Connector TerminalF39 1 Ground Battery voltage
+ −Continuity
Electrically-controlled cooling fan coupling
Connector TerminalF39 6 Ground Existed
Revision: 2010 May2011 QX56

EC-496
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
ELECTRICALLY-CONTROLLED COOLING FAN COUPLING
1. Start the engine.
2. Perform “FAN DUTY CONTROL” in “ACTIV
E TEST” mode of “ECM” with CONSULT-III.
3. Set the Duty value to 100%.
4. Check the voltage between electrically-controll ed cooling fan coupling harness connector and ground.
CAUTION:
Wait for 1 minute or more to measure.
WITHOUT CONSULT-III
1. Start the engine and warm up the engine until engine coolant temperature reaches at least 98 °C (209 °F).
2. Check the voltage between electrically-controll ed cooling fan coupling harness connector and ground.
CAUTION:
Wait for 1 minute or more to measure.
Is the inspection result normal?
YES >> GO TO 7.
NO >> GO TO 5.
5.CHECK ELECTRICALLY-CONTROLLED COOL ING FAN COUPLING CONTROL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R harness connector.
3. Check the continuity between electrically-contro lled cooling fan coupling harness connector and IPDM E/
R harness connector.
4. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 6.
+ −Vo l ta g e
(Approx.)
Electrically-controlled cooling fan coupling
Connector Terminal
F39 3 Ground 2. 5 V
+ −Vo l ta g e
(Approx.)
Electrically-controlled cooling fan coupling
Connector Terminal
F39 3 Ground 2. 5 V
JMMIA0404GB
JMMIA0404GB
+−
Continuity
Electrically-controlled cooling fan
coupling IPDM E/R
Connector Terminal Connector Terminal F39 3 E17 72 Existed
Revision: 2010 May2011 QX56