Good evening all.
Small thing. The beast threw the PO440 code for the second time the last one was back 18 months ago and I changed the gas cap. It was an aftermarket job. Ordered a OEM cap from Amazon. Will change it again and see what happens. I guess another cap could be fubar

Regards

 

Lol mine has been doing the same thing, but I think I got 3 times lol. I've been dealing with it, I even tried blowing out the canister in the back and a sensor under the hood. I think I got one more to try and I'll give up. Hope you get it figured, or atleast someone else has lol.

 

It may or may not be the gas cap. Your PCM does a routine test of the evap system to see if it will hold a vacuum/pressure when it closes both the vent and solenoid valve. The former is normally open and the latter is normally closed except for testing or vapor purging. If the system indicates a leak the computer sets either a small or large leak codes, depending on the rate of the leak. At that point you can have a leak in any component of the evap circuit: gas cap, canister, hoses, valves, etc. the other possibility is a failed pressure sensor giving a false reading. The gas cap is a common cause for this code but not the only possibility.

George

 

The gas cap from Amazon arrived this morning. It fits and even the tether that came with it fits in the hole. That has been broken since 2004.

See it that works. Will clear the code manually on Monday and take it from there..

Thanks for the comments. May need to look deeper but for now this is the simplest and most common cause


regards again

 

New Gas cap installed. Code and SES light cleared. Monitor to see if the SES light comes back on.

Regards

 

A leaking cap is the most common cause of an evap code. It's a major reason for the advent of capless fillers.