MarkInMLB

Hi everyone, new member and (used) 2006 2.2L AT LT owner. I've run into a problem right off the lot and I need some advice.

Got a CEL just as I was pulling off the lot after taking delivery. Returned, and the salesman said 'it was probably a O2 sensor, and they'd take care of it'. Well, not being very trusting of used car salesmen, I took it home and pulled the codes. It was indeed throwing a P0135 (O2 sensor heater) and a C0700 (can't figure that one out). Oh, and the mileage looks like under 20 mpg in a mostly highway cycle.

Returned to the dealer yesterday for something else (lousy job cleaning the interior, and an even lousier job correcting it -- any advice on cleaning "dingy" seats are most welcome! ), but "surprise, surprise", no CEL when I picked it up. Took it home and rechecked with the reader, and the codes are still there, but no light. The light still works, as I can see it temporarily on start.

Anyone know how a code can be thrown, without a CEL? Is the dealer just trying to pull something else by "saying" they fixed it (when they get the part), but in fact didn't even touch it?

Love the car, and it looks great (from the outside), just can't stand the BS with the dealership. Its already proving my own opinion that I have no business buying used cars. Thanks in advance for any/all advice.

ChevyMgr

If they are saying that they fixed it, then they didn't clear the code after the repairs.

MarkInMLB

Thanks for the reply ChevyMgr. I was hoping you'd chime in (yeah, I've been lurking...).

I don't think my OP was exactly clear (too much info). They haven't had the car back yet to supposedly replace the sensor, we're still waiting for another part so they can fix both at the same time (remote mirror switch). I guess you could just say I'm anticipating a problem when it does go back in. My real confusion/concern right now is that the CEL is not on, even though the code is still present when I scan it with my OBD II scanner. I would have thought this impossible, as the code being present should activate the CEL, no?

Thanks again for the response!

843de

With OBDII, vehicles can store a code for up to 100 cycles, a cycle being every time the ignition is turned on to start the vehicle. While the CEL can be extinguished by repairing the fault that caused it, the code will hang around in memory until a set amount of cycles have occurred without the fault returning.

That's why its important for dealers/techs to clear the codes after completing a repair to avoid having a false code set in memory.

firemangeorge

Don't see a C0700 code but there is a P0700.
P0700= Transmission Control Module(TCM)
Requested MIL Illumination

firemangeorge

Almost forgot. Welcome to the site MarkInMLB.

MarkInMLB

Thanks for all the input guys. I'll reset and watch to be sure nothing comes back. As for that C0700 code, I'll have to recheck that one. If it is the P0700, what does that actually mean? I did see that in the lists that ChevyMgr posted elsewhere, but glossed past it since I though I was pretty sure of my notes (but it wouldn't be the first mistake I've ever made :))

Thanks again!

whopper

Leave the code there - the dealer may have left it there for a reason. If you clear it, and it doesn't come back by the time you take it back in, they could refuse to install the new part(s) as it doesn't show any problems.

MarkInMLB

Thanks for everyone's input. It looks like the dealer did indeed correct the O2 sensor problem, as the P0135 code is now gone. I'll probably keep checking it over the next couple of weeks to be sure.

That other code is a puzzle, but I'm starting to think its a "ghost code" caused by an error with my scantool adapter. Everything seems to be running fine anyhow.

Again, thanks for everyone's advice!

firemangeorge

I think having a "ghost code" would be better than having "gremlins".