Cadillac Seville / Cadillac Eldorado Forum Discussion, P440 Code in Past Cadillac Vehicle Discussion; My service engine soon light came on and after checking codes I have a P 440 (current). Indicates a small ...
My service engine soon light came on and after checking codes I have a P 440 (current). Indicates a small leak. Anyone have any ideas where to start.
I have the same DTC setting on my 99 STS, start with the gas cap, inspect for a cut rubber seal or take a gamble and replace the gas cap. The second thing to check is for a sticking evaporative canister vent valve or a poor connection in the evaporative emission system. I tried a gas cap on mine it did not fix it I have to in deeper. I could also be a leak anywhere in the Evaporative Emission System. This requires a smoke machine to locate the leak.