P0451

P0451 EVAP Control System Pressure Sensor

Component Description

The EVAP control system pressure sensor (2) detects pressure in the purge line. The sensor output voltage to the ECM increases as pressure increases.





- EVAP canister vent control valve (1)
- Drain filter (3)
- EVAP canister (4)
- : Vehicle front





On Board Diagnosis Logic

If DTC P0451 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to [Power Supply and Ground Circuit Check] P0643.






DTC Confirmation Procedure

1) If DTC Confirmation Procedure has been previously conducted, always perform the following 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 "Diagnosis Procedure".

Diagnosis Procedure

1. CHECK GROUND CONNECTIONS

1 Turn ignition switch OFF.
2 Loosen and retighten three ground screws on the body. Refer to Power Supply and Ground Circuit Check.






OK or NG
OK
GO TO 2.
NG
Repair or replace ground connections.

2. CHECK EVPA CONTROL SYSTEM PRESSURE SENSOR CONNECTOR FOR WATER

1 Disconnect EVAP control system pressure sensor (2) harness connector.





- EVAP canister vent control valve (1)
- Drain filter (3)
- EVAP canister (4)
- : Vehicle front
1 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 "Component Inspection".

OK or NG
OK
GO TO 4.
NG
Replace EVAP control system pressure sensor. Refer to [EVAP Canister: Removal and Installation].

4. CHECK INTERMITTENT INCIDENT

Refer to [Service Information for Electrical Incident: Intermittent Incident] Intermittent Incident.


INSPECTION END

Component Inspection

EVAP Control System Pressure Sensor

1) Remove EVAP control system pressure sensor with its harness connector connected from EVAP canister.

Do not reuse the O-ring, replace it with a new one.
2) Install a vacuum pump to EVAP control system pressure sensor.
3) Turn ignition switch ON and check output voltage between ECM terminal 32 and ground 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).

4) If NG, replace EVAP control system pressure sensor.