Nissan Versa (N17): P0451 EVAP control system pressure sensor

DTC Logic

DTC DETECTION LOGIC

NOTE: If DTC P0451 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to EC344, "DTC Logic".

DTC No.	Trouble diagnosis name	DTC detecting condition	Possible cause
P0451	EVAP SYS PRES SEN (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 circuit is shorted.) [Crankshaft position sensor (POS) circuit is shorted.] (Battery current sensor circuit is shorted.) (Refrigerant pressure sensor circuit is shorted.) (Accelerator pedal position sensor 2 circuit is shorted.) EVAP control system pressure sensor Crankshaft position sensor (POS) Battery current sensor Refrigerant pressure sensor Accelerator pedal position sensor

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.

>> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDURE

1. 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.

Is 1st trip DTC detected?

YES >> Proceed to EC, "Diagnosis Procedure".

NO >> INSPECTION END

Diagnosis Procedure

1.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR FOR WATER

1. Turn ignition switch OFF.
2. Disconnect EVAP control system pressure sensor harness connector.
3. Check sensor harness connector for water.

Water should not exist.

Is the inspection result normal?

YES >> GO TO 2.

 NO >> Repair or replace harness connector.

2.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY

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

Is the inspection result normal?

YES >> GO TO 6.

NO >> GO TO 3.

3.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between EVAP control system pressure sensor harness connector and ECM harness connector. 

    4.   Also check harness for short to ground and to power.

Is the inspection result normal?

YES >> GO TO 4.

NO >> Repair or replace errordetected parts

4.CHECK SENSOR POWER SUPPLY CIRCUIT

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

*: With A/C models

Is the inspection result normal?

YES >> GO TO 5.

NO >> Repair short to ground or short to power in harness or connectors.

5.CHECK COMPONENTS

Check the following.

• Battery current sensor (Refer to EC, "Component Inspection").
• CKP sensor (POS) (Refer to EC, "Component Inspection").
• Refrigerant pressure sensor (Refer to EC, "Component Function Check").
• Accelerator pedal position sensor (Refer to EC, "Component Inspection").

Is the inspection result normal?

YES >> Check intermittent incident. Refer to GI, "Intermittent Incident".

NO >> Replace malfunctioning component.

6.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR GROUND CIRCUIT

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between EVAP control system pressure sensor harness connector and ECM harness connector 
4. Also check harness for short to power.

Is the inspection result normal?

YES >> GO TO 7.

NO >> Repair or replace errordetected parts.

7.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR SIGNAL CIRCUIT

    1.   Check the continuity between EVAP control system pressure sensor harness connector and ECM harness connector. 

    2.   Also check harness for short to ground and to power.

Is the inspection result normal?

YES >> GO TO 8.

NO >> Repair or replace errordetected parts.

8.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

Check the EVAP control system pressure sensor. Refer to EC, "Component Inspection".

Is the inspection result normal?

YES >> Check intermittent incident. Refer to GI, "Intermittent Incident".

NO >> Replace EVAP control system pressure sensor. Refer to FL, "Removal and Installation".

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 connected from EVAP canister.

   Always replace Oring 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 harness connector and ground under the following conditions. 

CAUTION:

• Always calibrate the vacuum pump gauge when using it.
• Do not 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).

Is the inspection result normal?

YES >> INSPECTION END

NO >> Replace EVAP control system pressure sensor. Refer to FL, "Removal and Installation".