2011 INFINITI QX56 ignition

P0447 EVAP CANISTER VENT CONTROL VALVEEC-327
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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Component Inspection (EVAP C
anister Vent Control Valve)INFOID:0000000006288312
1.CHECK EVAP CANISTER VENT CONTROL VALVE-I
1. Turn ignition switch OFF.
2. Remove EVAP canister vent c ontrol valve from EVAP canister.
3. Check portion (A) of EVAP canister vent control valve for rust.
Is it rusted?
YES >> Replace EVAP canister vent control valve. Refer to FL-
10, "Exploded View".
NO >> GO TO 2.
2.CHECK EVAP CANISTER VENT CONTROL VALVE-II
WITH CONSULT-III
1. Reconnect harness connectors disconnected.
2. Turn ignition switch ON.
3. Perform “VENT CONTROL/V” in “ACTIVE TEST” mode.
4. Check air passage continuity and operation delay time. Check that new O-ring is installed properly.
Operation takes less than 1 second.
WITHOUT CONSULT-III
1. Disconnect EVAP canister vent control valve harness connector.
2. Check air passage continuity and operation delay time under the following conditions. Check that new O-ring is installed properly.
Operation takes less than 1 second.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Replace EVAP canister vent control valve. Refer to FL-10, "
Exploded View".
3.CHECK EVAP CANISTER VENT CONTROL VALVE-III
WITH CONSULT-III
1. Clean the air passage [portion (A) to (B)] of EVAP canister vent control valve using an air blower.
2. Perform “VENT CONTROL/V” in “ACTIVE TEST” mode.
JSBIA0693ZZ
VENT CONTROL/V Condition Air passage continuity between (A) and (B)
ON Not existed
OFF Existed
JSBIA0694ZZ
Condition Air passage continuity between (A) and (B)
12 V direct current supply between
terminals 1 and 2 Not existed
OFF Existed
Revision: 2010 May2011 QX56

P0448 EVAP CANISTER VENT CONTROL VALVEEC-329
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0448 EVAP CANISTER VENT CONTROL VALVE
DTC LogicINFOID:0000000006288313
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. Turn ignition switch ON and wait at least 5 seconds.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and let it idle for at least 1 minute.
4. Repeat next procedures 3 times.
- Increase the engine speed up to between 3,000 and 3,500 rpm and maintain that speed for 2 minutes and
50 seconds to 3 minutes.
Do not exceed 3 minutes.
- Fully released accelerator pedal and keep engine idle for approximately 5 seconds.
5. Repeat next procedure 20 times.
- Quickly increase the engine speed up to between 4,000 and 4,500 rpm and maintain that speed for 25 to 30 seconds.
- Fully released accelerator pedal and keep engine idle for at least 35 seconds.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-329, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288314
1.CHECK RUBBER TUBE
1. Turn ignition switch OFF.
2. Disconnect rubber tube connected to EV AP canister vent control valve.
3. Check the rubber tube for clogging.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0448 VENT CONTROL VALVE
(EVAP canister vent control
valve close) EVAP canister vent control valve remains
closed under specified driving conditions.  EVAP canister vent control valve
 EVAP control system pressure sensor
and the circuit
 Blocked rubber tube to EVAP canister vent control valve
 EVAP canister is saturated with water
JMBIA1516GB
Revision: 2010 May2011 QX56

P0448 EVAP CANISTER VENT CONTROL VALVEEC-331
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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Component Inspection (EVAP C
anister Vent Control Valve)INFOID:0000000006288362
1.CHECK EVAP CANISTER VENT CONTROL VALVE-I
1. Turn ignition switch OFF.
2. Remove EVAP canister vent c ontrol valve from EVAP canister.
3. Check portion (A) of EVAP canister vent control valve for rust.
Is it rusted?
YES >> Replace EVAP canister vent control valve. Refer to FL-
10, "Exploded View".
NO >> GO TO 2.
2.CHECK EVAP CANISTER VENT CONTROL VALVE-II
WITH CONSULT-III
1. Reconnect harness connectors disconnected.
2. Turn ignition switch ON.
3. Perform “VENT CONTROL/V” in “ACTIVE TEST” mode.
4. Check air passage continuity and operation delay time. Check that new O-ring is installed properly.
Operation takes less than 1 second.
WITHOUT CONSULT-III
1. Disconnect EVAP canister vent control valve harness connector.
2. Check air passage continuity and operation delay time under the following conditions. Check that new O-ring is installed properly.
Operation takes less than 1 second.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Replace EVAP canister vent control valve. Refer to FL-10, "
Exploded View".
3.CHECK EVAP CANISTER VENT CONTROL VALVE-III
WITH CONSULT-III
1. Clean the air passage [portion (A) to (B)] of EVAP canister vent control valve using an air blower.
2. Perform “VENT CONTROL/V” in “ACTIVE TEST” mode.
JSBIA0693ZZ
VENT CONTROL/V Condition Air passage continuity between (A) and (B)
ON Not existed
OFF Existed
JSBIA0694ZZ
Condition Air passage continuity between (A) and (B)
12 V direct current supply between
terminals 1 and 2 Not existed
OFF Existed
Revision: 2010 May2011 QX56

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOREC-333
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0451 EVAP CONTROL SYSTEM
PRESSURE SENSOR
DTC LogicINFOID:0000000006288316
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 wait at least 40 seconds. NOTE:
Do not depress accelerator pedal even slightly.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-333, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288317
1.CHECK EVAP CONTRO L 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 SYS TEM PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ON.
2. Check the voltage between EVAP control system pressure sensor harness connector and ground.
DTC No. Trouble diagnosis name
(Trouble diagnosis con- tent) DTC detecting condition Possible cause
P0451 EVAP SYS PRES SEN
(EVAP control system
pressure sensor perfor-
mance) ECM detects a sloshing signal
from the EVAP control system
pressure sensor  (EVAP control system pressure sensor circuit is shorted.)
Harness or connectors
(Battery current sensor circuit is open or shorted.)
(Accelerator pedal position sensor 2 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 pressure sensor
 Battery current sensor
 Accelerator pedal position sensor
 Camshaft position sensor (bank 1)
 Crankshaft position sensor
 Refrigerant pressure sensor
EVAP control system
pressure sensor Ground Voltage (V)
Connector Terminal
C17 3 Ground Approx. 5 V
Revision: 2010 May2011 QX56

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOREC-335
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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>> INSPECTION END
Component Inspection (EVAP Cont
rol System Pressure Sensor)INFOID:0000000006288318
1.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Turn ignition switch OFF.
2. Remove EVAP control system pressure sensor with its harness connector. Always replace O-ring with a new one.
3. Install a vacuum pump to EVAP control system pressure sensor.
4. Turn ignition switch ON and check output voltage between ECM harness connector terminals under the
following conditions.
CAUTION:
 Always calibrate the vacuum pu mp gauge when using it.
 Never apply below -93.3 kPa (-0.952 kg/cm
2, -13.53 psi) or pressure over 101.3 kPa (1.033 kg/cm2,
14.69 psi).
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace EVAP control system pressure sensor.
ECM Condition
[Applied vacuum kPa (kg/cm
2, psi)] Voltage (V)
Connector +–
Terminal Terminal
E80 143 150 Not applied 1.8 - 4.8
-26.7 (-0.272, -3.87) 2.1 to 2.5 lower than above value
Revision: 2010 May2011 QX56

EC-336
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0452 EVAP CONTROL S
YSTEM PRESSURE SENSOR
P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
DTC LogicINFOID:0000000006288319
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:
Always perform test at a temperature of 5 °C (41 °F) or more.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
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. Turn ignition switch ON.
6. Select “DATA MONITOR” mode with CONSULT-III.
7. Check that “FUEL T/TM P SE” is more than 0°C (32 °F).
8. Start engine and wait at least 20 seconds.
9. Check 1st trip DTC.
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes to ECM harness connector terminals under the following conditions.
3. Check that the voltage is less than 4.2 V.
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.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0452 EVAP SYS PRES SEN
(EVAP control system pres-
sure sensor low input) An excessively low voltage from
the sensor is sent to ECM.  (EVAP control system pressure sensor circuit is short-
ed.)
Harness or connectors
(Battery current sensor circuit is open or shorted.)
(Accelerator pedal position sensor 2 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 pressure sensor
 Battery current sensor
 Accelerator pedal position sensor
 Camshaft position sensor (bank 1)
 Crankshaft position sensor
 Refrigerant pressure sensor
ECM
Connector +–
Terminal Terminal
E80 134
(Fuel tank temperature sensor signal) 175
Revision: 2010 May2011 QX56

P0452 EVAP CONTROL SYSTEM PRESSURE SENSOREC-337
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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8. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to
EC-337, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288320
1.CHECK EVAP CONTRO L 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 SYS TEM PRESSURE SENSOR POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ON.
2. Check the voltage between EVAP control system pressure sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 9.
NO >> GO TO 3.
3.CHECK EVAP CONTROL SYS TEM PRESSURE SENSOR POWER SUPPLY CIRCUIT-II
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.
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
ECM Sensor
Connector Terminal Name Connector Terminal
F110 76 Crankshaft position sensor F74 1
77 Camshaft position sensor (bank 1) F84 1
Revision: 2010 May2011 QX56

EC-338
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0452 EVAP CONTROL S
YSTEM PRESSURE SENSOR
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-414, "
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 14.
NO >> GO TO 8.
8.REPLACE ACCELERATOR PEDAL ASSEMBLY
Replace accelerator pedal assembly.
Refer to ACC-3, "
MODELS WITHOUT DISTANCE CONTROL ASS IST 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 system 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.
10.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between EVAP control system pressure sensor and ECM
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
ECM Sensor
Connector Terminal Name Connector Terminal
EVAP control system pressure sensor ECM
Continuity
Connector Terminal Connector Terminal
C17 1 E80 150 Existed
Revision: 2010 May2011 QX56