Nissan Maxima Service and Repair Manual: P0451 evap control system pressure sensor

Description

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

DTC Logic

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

NOTE: Never remove fuel filler cap during DTC confirmation procedure.

1.PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.

2.PERFORM DTC CONFIRMATION PROCEDURE-1

With CONSULT

1. Start engine and let it idle for least 40 seconds. NOTE: Do not depress accelerator pedal even slightly.
2. Check 1st trip DTC

3.PERFORM DTC CONFIRMATION PROCEDURE-2

With CONSULT

1. Select "EVAP DIAG READY" in "DATA MONITOR" mode of "ENGINE".
2. Let it idle until "OFF" of "EVAP DIAG READY" changes to "ON". NOTE: It will take at most 2 hours until "OFF" of "EVAP DIAG READY" changes to "ON".
3. Turn ignition switch OFF and wait at least 90 minutes. NOTE: Never turn ignition switch ON during 90 minutes.
4. Turn ignition switch ON.
5. Select "EVAP LEAK DIAG" in "DATA MONITOR" mode of "ENGINE".
6. Check that "EVAP LEAK DIAG" indication.

4.PERFORM DTC CONFIRMATION PROCEDURE-3

With CONSULT

Check 1st trip DTC.

5.PERFORM DTC CONFIRMATION PROCEDURE-4

With GST

1. Start engine and let it idle for least 40 seconds. NOTE: Do not depress accelerator pedal even slightly.
2. Check 1st trip DTC.

6.PERFORM DTC CONFIRMATION PROCEDURE-5

With GST

1. Let it idle for at least 2 hours
2. Turn ignition switch OFF and wait at least 90 minutes. NOTE: Never turn ignition switch ON during 90 minutes.
3. Turn ignition switch ON.
4. Check 1st trip DTC.

Diagnosis Procedure

1.CHECK GROUND CONNECTION

1. Turn ignition switch OFF.
2. Check ground connection E9.

2.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR FOR WATER

1. Disconnect EVAP control system pressure sensor harness connector.
2. Check that water is not inside connectors.

3.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT

1. Turn ignition switch ON.
2. Check the voltage between EVAP control system pressure sensor harness connector and ground.

4.CHECK SENSOR POWER SUPPLY CIRCUIT

Check harness for short to power and short to ground, between the following terminals.

5.CHECK COMPONENTS

Check the following.

• Crankshaft position sensor (POS) (Refer to EC-299, "Component Inspection".)
• Refrigerant pressure sensor

6.CHECK APP SENSOR

7.REPLACE ACCELERATOR PEDAL ASSEMBLY

1. Replace accelerator pedal assembly.

8.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

9.CHECK INTERMITTENT INCIDENT

Component Inspection

1.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

1. Turn ignition switch OFF.
2. Remove EVAP control system pressure sensor with its harness connector.

   Always replace O-ring with a new one.

3. Install a vacuum pump to EVAP control system pressure sensor.
4. Turn ignition switch ON and check output voltage between ECM terminals under the following conditions.

CAUTION:

•  Always calibrate the vacuum pump gauge when using it.
•  Never apply below -93.3 kPa (-0.952 kg/cm2, -13.53 psi) or pressure over 101.3 kPa (1.033 kg/cm2, 14.69 psi).