INFINITI QX56 2006 Factory Service Manual

EC-400Revision: November 2009
DTC P0448 EVAP CANISTER VENT CONTROL VALVE
2006 QX56
Component InspectionUBS00HB7
EVAP CANISTER VENT CONTROL VALVE With CONSULT-II
1. Remove EVAP canister vent control valve from EVAP canister.
2. Check portion B of EVAP canister vent control valve for being
rusted.
If NG, replace EVAP canister vent control valve.
If OK, go to next step.
3. Reconnect harness connectors disconnected.
4. Turn ignition switch ON.
5. Perform “VENT CONTROL/V ” in “ACTIVE TEST” mode.
6. Check air passage continuity and operation delay time. Make sure that new O-ring is installed properly.
Operation takes less than 1 second.
If NG, replace EVAP canister vent control valve.
If OK, go to next step.
7. Clean the air passage (Portion A to B ) of EVAP canister vent control valve using an air blower.
8. Perform step 6 again.
Without CONSULT-II
1. Remove EVAP canister vent control valve from EVAP canister.
2. Check portion B of EVAP canister vent control valve for being
rusted.
3. Check air passage continuity and operation delay time under the following conditions.
Make sure that new O-ring is installed properly.
Operation takes less than 1 second.
If NG, replace EVAP canister vent control valve.
If OK, go to next step.
4. Clean the air passage (Portion A to B ) of EVAP canister vent control valve using an air blower.
PBIB1033E
Condition VENT CONTROL/V Air passage continuity between A and B
ON No
OFF Yes
PBIB1679E
PBIB1033E
Condition Air passage continuity between A and B
12V direct current supply between
terminals 1 and 2 No
OFF Yes
PBIB1034E

DTC P0448 EVAP CANISTER VENT CONTROL VALVEEC-401
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Revision: November 2009 2006 QX56
5. Perform step 3 again.

EC-402Revision: November 2009
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
2006 QX56
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSORPFP:22365
Component DescriptionUBS00H56
The EVAP control system pressure sensor detects pressure in the purge line. The sensor output voltage to the
ECM increases as pressure increases.
CONSULT-II Reference Value in Data Monitor ModeUBS00H57
Specification data are reference values.
On Board Diagnosis LogicUBS00H58
NOTE:
If DTC P0451 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to
EC-460, "
DTC P0643 SENSOR POWER SUPPLY" .
BBIA0443E
PBIB1207E
MONITOR ITEMCONDITION SPECIFICATION
EVAP SYS PRES

Ignition switch: ON Approx. 1.8 - 4.8V
DTC No. Trouble diagnosis nameDTC detecting conditionPossible cause
P0451
0451 EVAP control system pressure
sensor performance ECM detects a sloshing signal from the
EVAP control system pressure sensor

Harness or connectors

EVAP control system pressure sensor

DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOREC-403
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Revision: November 2009 2006 QX56
DTC Confirmation ProcedureUBS00H59
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 OFF and wait at least 10 seconds.
2. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
3. Start engine and wait at least 40 seconds. NOTE:
Do not depress accelerator pedal even slightly.
If 1st trip DTC is detected, go to EC-403, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic ProcedureUBS00H5A
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-150, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
SEF194Y
BBIA0354E

EC-404Revision: November 2009
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
2006 QX56
2. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR FOR WATER
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check sensor harness connector for water.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace harness connector.
3. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to EC-404, "
Component Inspection" .
OK or NG
OK >> GO TO 4.
NG >> Replace EVAP control system pressure sensor.
4. CHECK INTERMITTENT INCIDENT
Refer to EC-144, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
For wiring diagram, refer to EC-407, "
Wiring Diagram" .
>> INSPECTION END
Component InspectionUBS00H5B
EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Remove EVAP control system pressure sensor with its harness connector connected from EVAP canister.
Always replace O-ring with a new one.
2. Install a vacuum pump to EVAP control system pressure sensor.
3. Turn ignition switch ON and check output voltage between ECM terminal 32 and ground under the following conditions.
CAUTION:

Always calibrate the vacuum pump gauge when using it.

Do not apply below -93.3 kPa (-700 mmHg, -27.56 inHg) or
pressure over 101.3 kPa (760 mmHg, 29.92 inHg).
4. If NG, replace EVAP control system pressure sensor. Water should not exist.
BBIA0443E
Applied vacuum kPa
(mmHg, inHg) Voltage V
Not applied 1.8 - 4.8
-26.7 (-200, -7.87) 2.1 to 2.5V lower than above value
PBIB1173E

DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOREC-405
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Revision: November 2009 2006 QX56
DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSORPFP:25085
Component DescriptionUBS00H5C
The EVAP control system pressure sensor detects pressure in the purge line. The sensor output voltage to the
ECM increases as pressure increases.
CONSULT-II Reference Value in Data Monitor ModeUBS00H5D
Specification data are reference values.
On Board Diagnosis LogicUBS00H5E
NOTE:
If DTC P0452 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to
EC-460, "
DTC P0643 SENSOR POWER SUPPLY" .
BBIA0443E
PBIB1207E
MONITOR ITEMCONDITION SPECIFICATION
EVAP SYS PRES

Ignition switch: ON Approx. 1.8 - 4.8V
DTC No. Trouble diagnosis nameDTC detecting conditionPossible cause
P0452
0452 EVAP control system pressure
sensor low input An excessively low voltage from the
sensor is sent to ECM.

Harness or connectors
(The sensor circuit is open or shorted.)

EVAP control system pressure sensor

EC-406Revision: November 2009
DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
2006 QX56
DTC Confirmation ProcedureUBS00H5F
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:
Always perform test at a temperature of 5°C (41 °F) or more.
WITH CONSULT-II
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. Select “DATA MONITOR ” mode with CONSULT-II.
5. Make sure that “FUEL T/TMP SE ” is more than 0°C (32 °F).
6. Start engine and wait at least 20 seconds. If 1st trip DTC is detected, go to EC-408, "
Diagnostic Procedure"
.
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Check that voltage between ECM terminal 107 (Fuel tank tem-
perature sensor signal) and ground is less than 4.2V.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and wait at least 20 seconds.
5. Select Service $07 with GST. If 1st trip DTC is detected, go to EC-408, "
Diagnostic Procedure"
.
SEF194Y
PBIB1110E

DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOREC-407
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Revision: November 2009 2006 QX56
Wiring DiagramUBS00H5G
BBWA2096E

EC-408Revision: November 2009
DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
2006 QX56
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
Diagnostic ProcedureUBS00H5H
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-150, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2. CHECK CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check sensor harness connector for water.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace harness connector.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
32 L EVAP control system pressure
sensor [Ignition switch: ON]
Approximately 1.8 - 4.8V
48 SB Sensor power supply
(EVAP control system pressure
sensor) [Ignition switch: ON]
Approximately 5V
67 B Sensor ground [Engine is running]

Warm-up condition

Idle speed
Approximately 0V
BBIA0354E
Water should not exist.
BBIA0443E

DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOREC-409
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Revision: November 2009 2006 QX56
3. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ON.
2. Check voltage between EVAP control system pressure sensor terminal 3 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors C1, E41

Harness connectors E5, F14

Harness for open or short between EVAP control system pressure sensor and ECM
>> Repair open circuit or short to ground or short to power in harness or connectors.
5. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND
SHORT1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between EVAP control system pressure sensor terminal 1 and ECM terminal 67.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors C1, E41

Harness connectors E5, F14

Harness for open or short between EVAP control system pressure sensor and ECM
>> Repair open circuit or short to ground or short to power in harness or connectors.
Voltage: Approximately 5V
PBIB0138E
Continuity should exist.