2006 INFINITI QX56 sensor

DTC P0448 EVAP CANISTER VENT CONTROL VALVEEC-395
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Revision: November 2009 2006 QX56
DTC P0448 EVAP CANISTER VENT CONTROL VALVEPFP:16935
Component DescriptionUBS00HB1
The EVAP canister vent control valve is located on the EVAP canis-
ter and is used to seal the canister vent.
This solenoid valve responds to signals from the ECM. When the
ECM sends an ON signal, the coil in the solenoid valve is energized.
A plunger will then move to seal the canister vent. The ability to seal
the vent is necessary for the on board diagnosis of other evaporative
emission control system components.
This solenoid valve is used only for diagnosis, and usually remains
opened.
When the vent is closed, under normal purge conditions, the evapo-
rative emission control system is depressurized and allows EVAP
Control System diagnosis.
CONSULT-II Reference Value in Data Monitor ModeUBS00HB2
Specification data are reference values.
On Board Diagnosis LogicUBS00HB3
PBIB1263E
BBIA0443E
MONITOR ITEMCONDITION SPECIFICATION
VENT CONT/V

Ignition switch: ON OFF
DTC No. Trouble diagnosis nameDTC detecting condition Possible cause
P0448
0448 EVAP canister vent con-
trol 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

DTC P0448 EVAP CANISTER VENT CONTROL VALVEEC-399
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Revision: November 2009 2006 QX56
3. CHECK IF EVAP CANISTER SATURATED WITH WATER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
2. Check if water will drain from the EVAP canister.
Ye s o r N o
Ye s > > G O T O 4 .
No >> GO TO 6.
4. CHECK EVAP CANISTER
Weigh the EVAP canister with the EVAP canister vent control valve and EVAP control system pressure sensor
attached.
The weight should be less than 2.5 kg (5.5 lb).
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.

EVAP canister for damage

EVAP hose between EVAP canister and vehicle frame for clogging or poor connection
>> Repair hose or replace EVAP canister.
6. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check connectors for water.
OK or NG
OK >> GO TO 7.
NG >> Replace EVAP control system pressure sensor.
7. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to EC-404, "
Component Inspection" .
OK or NG
OK >> GO TO 8.
NG >> Replace EVAP control system pressure sensor.
8. CHECK INTERMITTENT INCIDENT
Refer to EC-144, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
BBIA0351E
Water should not exist.

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