2007 INFINITI QX56 DTC

EC-386
< SERVICE INFORMATION >
DTC P0448 EVAP CANISTER VENT CONTROL VALVE
DTC P0448 EVAP CANISTER VENT CONTROL VALVE
Component DescriptionINFOID:0000000003531882
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 ModeINFOID:0000000003531883
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531884
DTC Confirmation ProcedureINFOID:0000000003531885
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 ON and wait at least 5 seconds.
2. Turn ignition switch OFF and wait at least 10 seconds.
PBIB1263E
BBIA0443E
MONITOR ITEM CONDITION SPECIFICATION
VENT CONT/V • Ignition switch: ON OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0448
0448EVAP canister vent con-
trol valve closeEVAP 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 VALVE
EC-387
< SERVICE INFORMATION >
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3. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
4. Start engine and let it idle for at least 1 minute.
5. Repeat next procedures 3 times.
a. Increase the engine speed up to 3,000 to 3,500 rpm and keep it
for 2 minutes and 50 seconds to 3 minutes.
Never exceed 3 minutes.
b. Fully released accelerator pedal and keep engine idle for about
5 seconds.
6. If 1st trip DTC is detected, go to EC-389, "
Diagnosis Procedure".
If 1st trip DTC is not detected, go to the next step.
7. Repeat next procedure 20 times.
a. Quickly increase the engine speed up to 4,000 to 4,500 rpm or more and keep it for 25 to 30 seconds.
b. Fully released accelerator pedal and keep engine idle for at least 35 seconds.
8. If 1st trip DTC is detected, go to EC-389, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
SEF058Y
PBIB0972E

EC-388
< SERVICE INFORMATION >
DTC P0448 EVAP CANISTER VENT CONTROL VALVE
Wiring Diagram
INFOID:0000000003531886
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.
BBWA2095E

DTC P0448 EVAP CANISTER VENT CONTROL VALVE
EC-389
< SERVICE INFORMATION >
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Diagnosis ProcedureINFOID:0000000003531887
1.CHECK RUBBER TUBE
1. Turn ignition switch OFF.
2. Disconnect rubber tube connected to EVAP canister vent control valve.
3. Check the rubber tube for clogging.
OK or NG
OK >> GO TO 2.
NG >> Clean rubber tube using an air blower.
2.CHECK EVAP CANISTER VENT CONTROL VALVE
Refer to EC-390, "
Component Inspection".
OK or NG
OK >> GO TO 3.
NG >> Replace EVAP canister vent control valve.
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
Yes >> GO TO 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.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
111 W / BECM relay
(Self shut-off)[Engine is running]
[Ignition switch: OFF]
• For a few seconds after turning ignition
switch OFF0 - 1.5V
[Ignition switch: OFF]
• More than a few seconds after turning igni-
tion switch OFFBATTERY VOLTAGE
(11 - 14V)
11 7 L / YEVAP canister vent control
valve[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
BBIA0443E
BBIA0351E

EC-390
< SERVICE INFORMATION >
DTC P0448 EVAP CANISTER VENT CONTROL VALVE
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-394, "
Component Inspection".
OK or NG
OK >> GO TO 8.
NG >> Replace EVAP control system pressure sensor.
8.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Component InspectionINFOID:0000000003531888
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.Water should not exist.
PBIB1033E

DTC P0448 EVAP CANISTER VENT CONTROL VALVE
EC-391
< SERVICE INFORMATION >
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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.
5. Perform step 3 again.
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 2No
OFF Yes
PBIB1034E

EC-392
< SERVICE INFORMATION >
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
Component DescriptionINFOID:0000000003531889
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 ModeINFOID:0000000003531890
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531891
NOTE:
If DTC P0451 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to
EC-447
.
DTC Confirmation ProcedureINFOID:0000000003531892
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.
BBIA0443E
PBIB1207E
MONITOR ITEM CONDITION SPECIFICATION
EVAP SYS PRES • Ignition switch: ON Approx. 1.8 - 4.8V
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0451
0451EVAP control system pressure
sensor performanceECM 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 SENSOR
EC-393
< SERVICE INFORMATION >
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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-393, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnosis ProcedureINFOID:0000000003531893
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-143, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
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-394, "
Component Inspection".
OK or NG
OK >> GO TO 4.
SEF194Y
BBIA0354E
Water should not exist.
BBIA0443E