ground INFINITI QX56 2011 Factory Service Manual

EC-342
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0453 EVAP CONTROL S
YSTEM PRESSURE SENSOR
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Turn ignition switch ON.
6. Turn ignition switch OFF and wait at least 10 seconds.
7. Start engine and wait at least 20 seconds.
8. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-342, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288323
1.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check that water is not inside connectors.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace harness connector.
2.CHECK EVAP CONTROL SY STEM PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ON.
2. Check the voltage between EVAP control syst em pressure sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 9.
NO >> GO TO 3.
3.CHECK EVAP CONTROL SYST EM PRESSURE SENSOR POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between EVAP control system pressure sensor harness connector and ECM har-
ness connector.
Is the inspection result normal?
YES >> GO TO 5.
NO >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open between ECM and EVAP control system pressure sensor
 Loose or poor connection for each connector and harness
>> Repair open circuit.
5.CHECK SENSOR POWER SUPPLY CIRCUIT
Check harness for short to power and short to ground, between the following terminals.
EVAP control system pressure sensor Ground Voltage (V)
Connector Terminal
C17 3 Ground Approx. 5
EVAP control system pressure sensor ECM Continuity
Connector Terminal Connector Terminal
C17 3 E80 133 Existed
Revision: 2010 May2011 QX56

P0453 EVAP CONTROL SYSTEM PRESSURE SENSOREC-343
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Is the inspection result normal?
YES >> GO TO 6.
NO >> Repair short to ground or short to power in harness or connectors.
6.CHECK COMPONENTS
Check the following.
 Crankshaft position sensor (Refer to EC-301, "
Component Inspection (Crankshaft Position Sensor)".)
 Camshaft position sensor (bank 1) (Refer to EC-306, "
Component Inspection (Camshaft Position Sensor)".)
 Battery current sensor (Refer to EC-427, "
Component Inspection (Battery Current Sensor)".)
 Refrigerant pressure sensor (Refer to EC-520, "
Component Function Check".)
Is the inspection result normal?
YES >> GO TO 7.
NO >> Replace malfunctioning component.
7.CHECK APP SENSOR
Refer to EC-470, "
Component Inspection (Accelerator Pedal Position Sensor)".
Is the inspection result normal?
YES >> GO TO 19.
NO >> GO TO 8.
8.REPLACE ACCELERATOR PEDAL ASSEMBLY
Replace accelerator pedal assembly.
Refer to ACC-3, "
MODELS WITHOUT DISTANCE CONTROL ASSI ST SYSTEM : Removal and Installation"
(Without distance control assist system)
Refer to ACC-4, "
MODELS WITH DISTANCE CONTROL ASSI ST SYSTEM : Removal and Installation" (With
distance control assist system).
>> INSPECTION END
9.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between EVAP control syst em pressure sensor harness connector and ECM har-
ness connector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 11.
NO >> GO TO 10.
ECM Sensor
Connector Terminal Name Connector Terminal
F110 76 Crankshaft position sensor F74 1
77 Camshaft position sensor (bank 1) F84 1
E80 133EVAP control system pressure sen-
sor
C17 3
Battery current sensor E63 2
Refrigerant pressure sensor E77 1
131 APP sensor 2 (Without ICC) E110 1
APP sensor 2 (with ICC) E67 9
EVAP control system
pressure sensor ECM
Continuity
Connector Terminal Connector Terminal
C17 1 E80 150 Existed
Revision: 2010 May2011 QX56

EC-344
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0453 EVAP CONTROL S
YSTEM PRESSURE SENSOR
10.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between EVAP control system pressure sensor and ECM
 Loose or poor connection for each connector and harness
>> Repair open circuit, short to ground or short to power in harness or connectors.
11 .CHECK EVAP CONTROL SYSTEM PRESSURE SEN SOR INPUT SIGNAL CIRCUIT FOR OPEN AND
SHORT
1. Check the continuity between EVAP control system pressure sensor harness connector and ECM har-
ness connector.
2. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 13.
NO >> GO TO 12.
12.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between EVAP control system pressure sensor and ECM
 Loose or poor connection for each connector and harness
>> Repair open circuit, short to ground or short to power in harness or connectors.
13.CHECK RUBBER TUBE
1. Disconnect rubber tube connected to EVAP c anister vent control valve. Refer to FL-10, "
Hydraulic Lay-
out".
2. Check the rubber tube for clogging.
Is the inspection result normal?
YES >> GO TO 14.
NO >> Clean the rubber tube using an air blower, repair or replace rubber tube.
14.CHECK EVAP CANISTER VENT CONTROL VALVE
Refer to EC-327, "
Component Inspection (EVAP Canister Vent Control Valve)".
Is the inspection result normal?
YES >> GO TO 15.
NO >> Replace EVAP canister vent control valve. Refer to FL-10, "
Exploded View".
15.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to EC-335, "
Component Inspection (EVAP Control System Pressure Sensor)".
Is the inspection result normal?
YES >> GO TO 16.
NO >> Replace EVAP control system pressure sensor. Refer to FL-10, "
Exploded View".
16.CHECK IF EVAP CANISTER IS SATURATED WITH WATER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
EVAP control system
pressure sensor ECM
Continuity
Connector Terminal Connector Terminal
C17 2 E80 143 Existed
Revision: 2010 May2011 QX56

EC-368
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P0527 COOLING FAN SPEED SENSOR
2.CHECK COOLING FAN SPEED SENSOR POWER SUPPLY CIRCUIT-II
1. Check the voltage between electrically-controlled cooling fan coupling harness connector and the ground.
Is inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness connector for short to power and short to ground, between the following terminals.
Is inspection result normal?
YES >> Perform the trouble diagnosis for power supply circuit. Refer to EC-168, "Diagnosis Procedure".
NO >> Repair or replace error-detected parts.
4.CHECK COOLING FAN SPEED SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between electrically-contro lled cooling fan coupling harness connector and ECM har-
ness connector.
Is inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace error-detected parts.
5.CHECK ECM GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between ECM harness connector and the ground.
+
−Vol tag e
(Approx.)
Electrically-controlled cooling fan coupling
Connector terminalF39 2 Ground 5 V
ECM Sensor
Connector Terminal Name Connector Terminal
F 111 27Low fuel pressure sensor F25 3
Power steering pressure sensor F35 1
Cooling fan speed sensor F39 2
28 FRP sensor F26 1
+ −
Continuity
Electrically-controlled cooling fan
coupling ECM
Connector Terminal Connector Terminal F 3 9 4 F 111 4 5 E x i s t e d
Revision: 2010 May2011 QX56

P0527 COOLING FAN SPEED SENSOREC-369
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Is inspection result normal?
YES >> Check intermittent incident. Refer to
GI-40, "Intermittent Incident".
NO >> Repair or replace error-detected parts.
6.CHECK COOLING FAN SPEED SENSOR SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between electrically-contro lled cooling fan coupling harness connector and ECM har-
ness 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 COOLING FAN SPEED SENSOR
1. Reconnect all harness connectors disconnected.
2. Perform cooling fan speed sensor component inspection. Refer to EC-369, "
Component Inspection (Cool-
ing Fan Speed Sensor)".
Is inspection result normal?
YES >> GO TO 8.
NO >> Replace electrically-controlled cooling fan coupling.
8.CHECK COOLING FAN ROTATIONAL CONDITION
Rotate the cooling fan by hand.
Dose the cooling fan rotates smoothly?
YES >> GO TO 9.
NO >> Check that the cooling fan is not interfered with other parts.
9.CHECK ELECTRICALLY-CONTROLLED COOLING FAN COUPLING SYSTEM
Refer to EC-495, "
Diagnosis Procedure".
Is inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
NO >> Repair or replace error-detected parts.
Component Inspection (C ooling Fan Speed Sensor)INFOID:0000000006217869
1.CHECK COOLING FAN SPEED SENSOR
1. Turn ignition switch OFF.
2. Disconnect electrically-controlled c ooling fan coupling harness connector.
3. Rotate the electrically-controlled cooling fan coupling slowly with hand and check the voltage between
electrically-controlled cooling fan coupling c onnector terminals under the following conditions.
+
−Continuity
ECM
Connector Terminal F 111 1 0 Ground Existed
E80 174
175
+
−
Continuity
Electrically-controlled cooling fan
coupling ECM
Connector Terminal Connector Terminal F39 5 F111 37 Existed
Revision: 2010 May2011 QX56

EC-370
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0527 COOLING FAN SPEED SENSOR
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace Electrically-controlled cooling fan coupling.
+
−
Condition Voltage (V)
(Approx.)
Electrically-controlled
cooling fan coupling
Te r m i n a l
54  5V direct current supply to terminal 2
 Terminal 4 connect to ground 0
⇔ 5
NOTE:
The voltage is in waveform
Revision: 2010 May2011 QX56

P0550 PSP SENSOREC-371
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P0550 PSP SENSOR
DTC LogicINFOID:0000000006217870
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.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for at least 5 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-371, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217871
1.CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect power steering pressure (PSP) sensor harness connector.
3. Turn ignition switch ON.
4. Check the voltage between PSP sensor harness connector terminals.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-II
1. Check the voltage between PSP sensor harness connector and the ground.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0550 PW ST P SEN/CIRC
(Power steering pressure
sensor circuit) An excessively low or high voltage from the
sensor is sent to ECM.  Harness or connectors
(The Fuel rail pressure sensor circuit is
open or shorted.)
(The Power steering pressure sensor cir-
cuit is open or shorted)
(The Electrically-controlled cooling fan
coupling circuit is open or shorted)
 Fuel rail pressure sensor
 Power steering pressure sensor
 Electrically-controlled cooling fan cou- pling
PSP sensor Vo l ta g e
(Approx.)
Connector +
−
terminal
F35 1 3 5 V
Revision: 2010 May2011 QX56

EC-372
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0550 PSP SENSOR
Is inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness connector for short to power and short to ground, between the following terminals.
Is inspection result normal?
YES >> Perform the trouble diagnosis for power supply circuit. Refer to EC-168, "Diagnosis Procedure".
NO >> Repair or replace error-detected parts.
4.CHECK PSP SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between PSP sens or harness connector and ECM harness connector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace error-detected parts.
5.CHECK ECM GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between ECM harness connector and the ground.
Is inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
+
−Voltag e
(Approx.)
PSP sensor
Connector terminal F35 1 Ground 5 V
ECM Sensor
Connector Terminal Name Connector Terminal
F 111 27Low fuel pressure sensor F25 3
Power steering pressure sensor F35 1
Cooling fan speed sensor F39 2
28 FRP sensor F26 1
+ −
Continuity
PSP sensor ECM
Connector Terminal Connector Terminal F35 3 F111 45 Existed
+ −Continuity
ECM
Connector Terminal F 111 1 0 Ground Existed
E80 174
175
Revision: 2010 May2011 QX56

P0550 PSP SENSOREC-373
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NO >> Repair or replace error-detected parts.
6.CHECK PSP SENSOR SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between PSP sens or harness connector and ECM harness connector.
4. Also check harness for short to ground and to power.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair or replace error-detected parts.
7.CHECK PSP SENSOR
Refer to EC-373, "
Component Inspection (Power Steering Pressure Sensor)".
Is the inspection result normal?
YES >> GO TO 8.
NO >> Replace PSP sensor.
8.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (Power Steering Pressure Sensor)INFOID:0000000006217872
1.CHECK POWER STEERING PRESSURE SENSOR
1. Turn ignition switch OFF.
2. Reconnect all harness connectors disconnected.
3. Start engine and let it idle.
4. Check the voltage between ECM harness connector terminals under the following conditions.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace power steering pressure sensor.
+ −
Continuity
PSP sensor ECM
Connector Terminal Connector Terminal F35 2 F111 39 Existed
ECM Condition Voltage (V)
Connector +–
Te r m i n a l Te r m i n a l
F111 39 45 Steering wheel Being turned 0.5 - 4.5
Not being turned 0.4 - 0.8
Revision: 2010 May2011 QX56

P0643 SENSOR POWER SUPPLYEC-381
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P0643 SENSOR POWER SUPPLY
DTC LogicINFOID:0000000006217882
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-381, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217883
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 6.
NO >> GO TO 2.
2.CHECK SENSOR POWER SUPPLY CIRCUIT
Check harness for short to power and short to ground, between the following terminals.
DTC No.Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0643 SENSOR POWER/CIRC
(Sensor power su
pply circuit
short) ECM detects that the voltage of
power source for sensor is ex-
cessively low or high.  Harness or connectors
(Accelerator pedal position sensor 1 circuit is shorted.)
[Camshaft position sensor (bank 2) circuit is shorted.]
[Manifold absolute pressure (MAP) sensor circuit is
shorted.]
(Throttle position sensor circuit is shorted.)
 Accelerator pedal position sensor 1
 Camshaft position sensor (bank 2)
 Manifold absolute pressure (MAP) sensor
 Throttle position sensor
APP sensor Ground Voltage (V)
Connector Terminal
E110 (Without ICC) 2 Ground Approx. 5
E67 (With ICC) 12
Revision: 2010 May2011 QX56