EVAP System Malfunction

P0451 DETECTION CONDITION AND POSSIBLE CAUSES

P0451

EVAP SYSTEM MALFUNCTION

DETECTION CONDITION

P0451 indicates the fuel tank pressure changes greater than 14 in-H₂ O in 0.10 seconds (sensor circuit noisy).
P0461 indicates the fuel level input noisy.

POSSIBLE CAUSE

Intermittent open or short in the FTP sensor circuit (P0451).
Intermittent open or short in the FLI circuit (P0461).

HINT

Fuel Tank Pressure Sensor Description

Used to measures the fuel tank pressure during the EVAP monitor test and to control excessive fuel tank pressure by forcing the system to purge.

Fuel Level Input Description

Indicates the fuel level in the tank.
Hard wire signal input to the PCM from the fuel tank unit.

P0451 DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	PCM QUICK TEST Was PCM Quick Test performed?	Yes	If any other DTC is present, go to applicable DTC Troubleshooting. If only DTC P0451 and/or P0461 are present, See TEST 3: INTERMITTENT .
1	PCM QUICK TEST Was PCM Quick Test performed?	No	Perform PCM Quick Test. See PCM QUICK TEST .