Possible causes

Blockages or kinks in the EVAP canister tube or EVAP canister purge outlet tube (between the fuel tank, EVAP the canister purge valve and the EVAP canister).

Fuel filler cap stuck closed (no vacuum relief).

Contaminated fuel vapor elbow on the EVAP canister.

Restricted EVAP canister.

CV solenoid stuck open (partially or fully).

Plugged CV solenoid filter.

EVAP canister purge valve stuck open.

VREF circuit open (harness near FTP sensor, FTP sensor or PCM).

Damaged FTP sensor.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1450 Description

Monitors the fuel vapor vacuum and pressure in the fuel tank. System failure occurs when the EVAP running loss monitor detects excessive fuel tank vacuum with the engine running (but not at idle).

P1450 Information for specific makes

P1450 ACURA
P1450 BUICK
P1450 CADILLAC
P1450 CHEVROLET
P1450 FORD
P1450 GMC