2007 INFINITI QX56 engine

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

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.
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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

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

DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
EC-395
< SERVICE INFORMATION >
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DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
Component DescriptionINFOID:0000000003531895
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:0000000003531896
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531897
NOTE:
If DTC P0452 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to
EC-447
.
DTC Confirmation ProcedureINFOID:0000000003531898
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.
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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
P0452
0452EVAP control system pressure
sensor low inputAn excessively low voltage from the sen-
sor is sent to ECM.• Harness or connectors
(The sensor circuit is open or shorted.)
• EVAP control system pressure sensor

EC-396
< SERVICE INFORMATION >
DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
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-398, "
Diagnosis 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-398, "
Diagnosis Procedure".
SEF194Y
PBIB1110E

EC-398
< SERVICE INFORMATION >
DTC P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
Diagnosis Procedure
INFOID:0000000003531900
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 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.
3.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ON.
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COLORITEM CONDITION DATA (DC Voltage)
32 LEVAP control system pressure
sensor[Ignition switch: ON]Approximately 1.8 - 4.8V
48 SBSensor power supply
(EVAP control system pressure
sensor)[Ignition switch: ON]Approximately 5V
67 B Sensor ground[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
BBIA0354E
Water should not exist.
BBIA0443E

EC-402
< SERVICE INFORMATION >
DTC P0453 EVAP CONTROL SYSTEM PRESSURE SENSOR
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.
7. If 1st trip DTC is detected, go to EC-404, "
Diagnosis 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-404, "
Diagnosis Procedure".
SEF194Y
PBIB1110E

EC-404
< SERVICE INFORMATION >
DTC P0453 EVAP CONTROL SYSTEM PRESSURE SENSOR
Diagnosis Procedure
INFOID:0000000003531907
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 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.
3.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ON.
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NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
32 LEVAP control system pressure
sensor[Ignition switch: ON]Approximately 1.8 - 4.8V
48 SBSensor power supply
(EVAP control system pressure
sensor)[Ignition switch: ON]Approximately 5V
67 B Sensor ground[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
BBIA0354E
Water should not exist.
BBIA0443E