P0451

DTC P0451 EVAPORATIVE EMISSION CONTROL SYSTEM PRESSURE SENSOR RANGE/PERFORMANCE

CIRCUIT DESCRIPTION

DTC Detection Condition:

The Fuel Tank Pressure (FTP) sensor, the Evaporative Emissions (EVAP) Vacuum Switching Valve (VSV), Canister Closed Valve (CCV) and by-pass VSV are used to detect abnormalities in the EVAP control system. The ECM decides whether or not there is an abnormality in the EVAP system based on the FTP sensor signals.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions Part 1:

Typical Enabling Conditions Part 2:

Typical Malfunction Thresholds:

Component Operating Range:

P0451
The ECM monitors the FTP sensor in two ways. Either fault will set DTC P0451 and the ECM will illuminate the MIL.
a. One method examines the fluctuation of electrical signals while the engine is idling. If the pressure signal fluctuates beyond the specified range, the ECM interprets this as a noise in the FTP sensor.
b. The ECM also verifies that the pressure signal changes within the specified range. If the output of the sensor does not vary for 10 minutes while the intake air amount has been changing, the ECM interprets this as a fault in the FTP sensor.

Wiring Diagram:

Step 1 - 2:

Step 3:

INSPECTION PROCEDURE

HINT:
- If DTC P0441 (purge flow), P0446, P2418 (CCV or by-pass VSV), P0451, P0452 or P0453 (FTP sensor) is output with DTC P0442, P0455 or P0456, first troubleshoot DTC P0441, P0446, P2418, P0451, P0452 or P0453. If no malfunction is detected, troubleshoot DTC P0442, P0455 or P0456 next.
- Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was LEAN or RICH, etc. at the time of the malfunction.
- When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the FTP sensor.

CHECK FOR INTERMITTENT PROBLEMS

HINT: Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the hand-held tester is in check mode. In check mode, the hand-held tester uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.

a. Clear the DTCs.
b. Set the check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and the connector.