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2004 CTS - Check Engine Soon Light


newbold1

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Hey Everyone,

A few days ago my check engine soon light came on and I called On-Star to do a remote diagnosis. They said that the problem was that my gas cap was likely loose and that once I tightened it the light would eventually go off on its own. Sure enough the cap was loose so I assumed there was nothing more for me to do.

Well... after 3-4 days and probably 40 or more cycles (on/off) of the engine the light is still on. Does anyone know what its going to take to get that light to go off? Its really starting to worry me.

Thanks,

David

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Can't pull the codes... my OBD-2 scan tool just gets stuck on "READ" when I use it on this car. I tried it on my wife's 2000 Nissan Quest and it works just fine. I called On-Star again and they still say it was the fuel cap and that it will take up to 10 days for the code to clear and for the light to go out.

I do miss the on-board diagnostics that was available on my 1996 SLS.

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Oh, I just realized you have a CTS. Why in the world did they take the onboard diagnostics out of it. It is still supposed to be a Cadillac isn't it? What where they thinking?

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The systems have really gotten too complex to support the on board diagnostics. There are 4-500 codes on a newer Cadillac.

Scan tools are much faster then the onboard stuff. Also much of the onboard data was technically greek.

The GM service manuals do not even show the diagnostic access proceduers anymore. Every chart has you connect the Tech 2.

Cadillac was the only GM brand to support the onboard diagnostics. The rest of GM had to find a scan tool.

OBDII is now going to CAN. 'Controller area network.'

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Cadillac was the only GM brand to support the onboard diagnostics. The rest of GM had to find a scan tool.

And the Corvette. My brother just bought a '99 convert, and all the stuff in there is very familiar. IPC, PCM, RFA, etc. :)

Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

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I went for my oil change this weekend and had the dealership check out the problem with the engine light. It had been on for about 7 days at this point. It turns out that the fuel cap wasn't sealing properly. So they changed out the cap with a new one.

Crest Cadillac in north Nashville, TN was were I went and I thought I would mention them since they really took the time to make sure there was nothing else wrong. After they changed the cap they spent maybe 25-30 minutes checking everywhere to make sure they couldn't find a leak anywhere else. They wanted to make sure that the cap was the only problem they could find. I felt good knowing that they cared to be certain rather than just do the quick fix that might have led me to return with the problem again.

I'm just glad that it was a very simple problem with a very simple solution. :D

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  • 1 month later...
It is an emissions control requirement....gasoline vapors are bad for the environment too.

Charles

Oh ya I guess that would make sence I'm not a big fan of the service engine soon light theres way to many ways for them to come on if myn comes on I always feel like I should go get it checked out but i'm affraid they'll charge me 20 bucks just to say O your gas cap isn't screwed on right. Myn came on once but I think it was caused by my idle sensor cause after I replaced it the light went off.

user posted image

Defending Northstar perf a qtr mile at a time!!!!

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I thought on the newer cars, cts, sts, etc(not eldo, excetara) haha, the on-board dianostics were canned due to the complexity of everything in the new cars as well *smurf* too many codes. Is this true or am I wrong?

Chris

Christopher Petro

94 sts

67 coupe de Ville

user posted image

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I thought on the newer cars, cts, sts, etc(not eldo, excetara) haha, the on-board dianostics were canned due to the complexity of everything in the new cars as well *smurf* too many codes.  Is this true or am I wrong?

Chris

Read the posts above and the new on on the diagnostic codes I entered. The OBD2 system standardized all the diagnostic codes and functions so that ALL cars from ALL manufacturers use the same code numbers, can be accessed by the same universal scan tools and test for the same items as specified by the EPA. GM did not decide to eliminate anything....it had to comply with the ODB2 and later OBD requirements because they are mandated by federal law and enforced by the EPA. The Cadillacs always had a very sophisticated onboard diagnostic system so transitioning to the OBD2 system for 1996 was relatively painless and somewhat transparent. Cadillac actually had to DELETE a lot of the onboard systems to become compliant with the OBD2 regs. Believe it or not, other carlines and manufacturers (specifally European and Oriental vehicles) did not have ANY onboard diagnostics systems at all so the OBD2 regs were a complete new ball game. If you are dismayed at the loss of the onboard diagnostics of the Cadillacs then write your congressman....don't blame GM.

Haha, I guess i should read the whole thread before i comment. Interesting to know. Thanks.

Christopher Petro

94 sts

67 coupe de Ville

user posted image

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A month ago I was backing out of the garage and noticed the fuel door was open I closed it and while driving I noticed the service engine light was on. The next start stop cycle the light was out. I guess it can tell when the fuel door is open.Mike

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