Infiniti QX56 (JA60). Manual - part 397

EC-240

< COMPONENT DIAGNOSIS >

[VK56DE]

P0448 EVAP CANISTER VENT CONTROL VALVE

Weigh the EVAP canister with the EVAP canister vent control valve and EVAP control system pressure sensor

attached.

The weight should be less than 3.2 kg (7.1 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-243, "Component Inspection"

.

OK or NG

OK

>> GO TO 8.

NG

>> Replace EVAP control system pressure sensor.

8.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-35, "How to Check Terminal"

 and 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000005149261

EVAP CANISTER VENT CONTROL VALVE

 With CONSULT-III

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.

Water should not exist.

PBIB1033E

P0448 EVAP CANISTER VENT CONTROL VALVE

EC-241

< COMPONENT DIAGNOSIS >

[VK56DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

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-III

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

PBIB1033E

Condition

Air passage continuity between A and B

12V direct current supply between
 terminals 1 and 2

No

OFF

Yes

PBIB1034E

EC-242

< COMPONENT DIAGNOSIS >

[VK56DE]

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR

Component Description

INFOID:0000000005149262

The EVAP control system pressure sensor detects pressure in the purge line. The sensor output voltage to the

ECM increases as pressure increases.

On Board Diagnosis Logic

INFOID:0000000005149263

NOTE:

If DTC P0451 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to

EC-289

.

DTC Confirmation Procedure

INFOID:0000000005149264

1. If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next step.

a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c.

Turn ignition switch OFF and wait at least 10 seconds.

2. Start engine and wait at least 40 seconds.

NOTE:

Do not depress accelerator pedal even slightly.

3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to 

EC-242, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005149265

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten three ground screws on the body.

BBIA0443E

PBIB1207E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible 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

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR

EC-243

< COMPONENT DIAGNOSIS >

[VK56DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Refer to 

EC-85, "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-243, "Component Inspection"

.

OK or NG

OK

>> GO TO 4.

NG

>> Replace EVAP control system pressure sensor.

4.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-35, "How to Check Terminal"

 and 

GI-38, "Intermittent Incident"

.

For wiring diagram, refer to 

EC-246, "Diagnosis Procedure"

.

>> INSPECTION END

Component Inspection

INFOID:0000000005149266

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.

BBIA0354E

Water should not exist.

BBIA0443E