03 Cavalier

[DeanMoriarty]

My girl's car threw an evap emissions control code about a month ago. She took it to the shop and they replaced the purge canister solenoid. Now, it's throwing another code, the shop is telling her it's a different evap code and that she needs a fuel tank pressure sensor.
She's out of state for a few more weeks so I have no way to check it out right now. Is this something that can be let go until she's back here? She'll have to make a 10 hour drive to get here, so I really need to know if this part can effect the cars reliability, or if it's just another bullshit emissions part? What you guys think?

 

[Thumper113]

If it's a P0440, she should probably have it repaired fairly soon as that is the code that detects a large leak. A P0442, is one for a small leak. We keep purge solenoids & fuel tank pressure valves in stock because they leak quite often & cause one of the two codes. Crappy parts IMO.

This code won't affect reliability but if it's a large leak, she could be overwhelmed by gasoline fumes and/or it could leak fuel which isn't a good thing with the exhaust pipe next to the fuel tank on that model.

 

[DeanMoriarty]

Hell... it is a P0440.
Let me ask you this... I've read that evap errors on those things are difficult to diagnose and I've seen some people recommend going to a dealer service dept. to get a smoke test done. Is that pressure sensor fairly easy to diagnose when it fails? It sounds like she should get it fixed, but I'd hate for the shop to just be throwing parts at the problem if they're not positive of what it is. They told her it's nothing to worry about if it isn't causing any problems, to get it fixed when she can. From what you're saying... it sounds like it should have been something to worry about, if that's really the problem. I'm not sure what to have her do...

 

[Thumper113]

The "large leak" may not be large enough to leak fuel out of it but it's large enough to leak vacuum, more so of a vacuum leak than a P0442 is. Personally, if it was my vehicle, I wouldn't worry too much about it unless it leaked fuel or if I could smell gasoline fumes. However, I would get it repaired soon. Given her situation, she might be able to wait until you can fix it for her. Did they even test the fuel cap? That's the most common issue we see at work.

The smoke test works pretty good.

 

[DeanMoriarty]

Ok, understood.

Apparently they mentioned the possibility of doing a smoke test... but they didn't charge her anything for the diagnosis, so I'm guessing they didn't? They told her the tech spent two hours trying to figure out the problem... I'd hope he would have checked the fuel cap first. The whole thing sounds odd to me. If they have the capability to do the smoke test there... I'm not sure why they would have done two hours of troubleshooting instead. I'd have preferred they'd done the test and know for sure what the problem is.
I'm going to call them today and try to talk to the guy who looked at her car.

 

[DeanMoriarty]

Ok...
I talked to the mechanic. He tells me they did the smoke test and there are no leaks. (They didn't charge for it because they'd already replaced the canister solenoid, which didn't fix the problem) He says the pressure sensor is faulty, reading incorrectly, at 6lbs of pressure regardless of how much pressure is actually in the tank. I believe he said this is somehow causing the purge valve to vent into the air, and it shouldn't be anything to really worry about. Does this sound plausible to you?

 

[Thumper113]

It only sounds plausible if he monitered the data on the scan tool & applied different pressures to the FPS. It probably isn't anything to really worry about as far as causing a problem but the pesky check engine light will stay on. It sounds like you'll have time to get it fixed when the time allows you to. It doesn't sound like anything that needs fixed right away.

 

[DeanMoriarty]

Yes I believe he did.

Thanks for the responses and advice. I appreciate it.