Contour Enthusiasts Group Archives Forums General Troubleshooting CEL with no codes.

I'm not really sure what to make of this. for the past 5 months I've had this CEL come on at complete random. And when I've had the codes pulled the mech said there were none in the system. I've reset several times and the CEL keeps coming back; sometimes in a month, others in a week, all of which are under normal driving conditions. I have not noticed ANYTHING wrong with my car at all, it runs perfectly fine. I just want to get to the bottom of this random CEL.


any ideas?

Does it ever blink? I think blinking cel is a misfire on cyl no.1 Does it come one while driving and go away while driving, like a short period of time? Just trying to narrow down the behavior.
I think there are things like not completely tightening you gas cap that can throw a cel, probably other minor things too.

no it just stays on until I decide to clear it again (fuses 4 and 11 in the fuse box in engine bay).

no flashing, no on/off after starts. Once it comes on it stays on.

Well I dunno, maybe it's a glitch, not that that helps because I'm sure it's annoying. Kinda wierd.
My uncle had a contour that had the check engine light on, and he said that he had it diagnosed and it was nothing, so maybe your not the only one.

I had the same issue. I checked on another forum (forget which one) and also had the codes read. Here is the input I got (disclaimer - I am NOT a mechanic):

Water or debris in the gas can cause this. As gas prices went up ALL of my family's vehicles' mileage went down so I think the gas companies are using extenders in the gas. I switched to premium and the problem pretty much went away.

Since the CEL came on again a couple of more times, I took it to a mechanic who said there was a "soft" code for the o2 sensor in memory. He said that soft codes don't always show up on the meter, but because they are in the system, they can trigger the CEL light at random until they are cleared even if nothing is currently wrong.

So here is my lame advice: Switch to premium (permanently), run a couple of tanks through, then get the codes cleared.

I always vote for trying the easy things first.

For what it's worth,
Phoebe

If I'm not mistaken, doesn't the CEL have to be on at the time of code scanning?

If your code was not on at the time of scanning and you also reset the PCM, why would it show up?

Either that or your mechanic is due for a new OBD-II scanner.

My CEL was NOT on when the codes were read. It did come up with the code for a problem with the O2 sensor (which I did nothing about). Anyway, the engine always worked great and the light was completely random. Don't know if the switching-gas-and-clearing-codes trick really worked (at least the CEL has not returned)or if it was just one of those magic fixes, like kicking the tire to make the rear door latch unlock.

Phoebe

If the CEL is not on and you get a code when you have the car scanned, that code is called an Intermittent code. The computer detected a problem, than, the CEL come on and then the problem went away and the CEL went off. The code stays in memory until it is cleared. I just got done scanning my minivan as it was idling rough even though the CEL did not come on. Turns out the air filter housing was not closed properly (iffy ube replaced the air filter for me previously). I put in a new filter, closed the housing properly, cleared the CEL and will drive for a few days to see if the idling improves and the CEL (or intermittent code) stays off. The scanner is one of the best investments for me. ($75 for a Actron 9125, $150 for 9135 or $250 for 9145- And auto parts stores occasionally have them on sale for another 20% or so discount).

Things of note:
re: octane
If you aren't experiencing pinging, or the like, switching to premium (with a car not designed to use it) will likely not affect anything in the area of "extenders" Intermittent codes should be addressed by a thorough cleaning/maintenance of the intake tract, fuel filter, and lastly by running cleaner through the injectors, etc (basically, anything that can intermittently stick, leak, or clog)

re: codes
Intermittent codes are NOT stored until you clear them.. they are stored until the predetermined "Drive cycle" is completed. Some are as much as 80 starts, others 40, or 3. Each code is independant.

re: scanners.
If you own a laptop, then look in to Alex Pepper's OBD-II software. You already have the "scanner hardware" per se, you just need the software from the site.

www.obd-ii.com I believe..

much, much, much cheaper than the Autozone scanners, though if you prefer to hold the scanner in your hand, they are a good thing to have.