Can not clear CEL Check engine light ?

[jaxgt]

Gents,
Haven't driven my 2005 GT in a while. Had a nice day, went to take her out, and as soon as I start it up, I have a CEL on. While this is not that uncommon when I take it out after a bit of a rest, normally it's a running rich code of sorts that is easily cleard.

However, today, for some reason having an issue. When I hook up either my SCT handheld tuner or another code reading device I have (both of which normally work fine), both devices say no Error Codes and nothing to clear. Even when I hit clear all codes, still have the check engine light lit. Weird. Can't read a code and can't clear it.

Any advice appreciated.

Thanks and happy new year to all my GT friends!

 

[Howard]

Clamshell or frunk closure?

 

[jaxgt]

Would that throw a CEL?

 

[PL510*Jeff]

Frunk and Clamshell show as door ajar.

 

[jaxgt]

Frunk and Clamshell show as door ajar.

Thats what i thought. Its weird

 

[twobjshelbys]

Did you try to show pending codes? The light shouldn't be on if they're pending though.

 

[jaxgt]

Cant see any codes. Even when i clear any codes on either my SCT tuner or another device, stays on. Weird

 

[twobjshelbys]

First, are you sure they're being cleared? With the OBDII reader (not the SCT) can you call up the emissions readiness indicators and see if they are all cleared? If so then the code clear action also happened...

Speaking of which, how old is your battery???

Codes are also cleared if you disconnect the battery so you might try that. Disconnect overnight ...

Are you doing the clear with the engine running? I seem to recall something about just having the ignition in the on but not running state didn't clear.

 

[jaxgt]

When i connect either device I have (sct handheld tuner and another gizmo), as I have many times in past, it says No error codes present, in spite of CEL being on. Even if I hit clear all codes (when still says none), CEL stays on. Tried with car running and not, but ignition turned on). Weird. Never seen this before.

In past when car sat a while might get a CEL light, but always had a simple code that could be cleared.

 

[texas mongrel]

Dumb idea,but have you tried unhooking the battery for ten minutes?

 

[nota4re]

You sure CEL and not Check Gauges light?

 

[jaxgt]

Thanks for chiming in Kendall. I appreciate your expertise.

I didnt even know there is a check gauges light. I am not at car at moment, but am pretty (90+%) sure it was the yellow/orange colored engine icon that is lit. Will dbl check when back at it.

 

[PeteK]

The Check Gauges Light (CGL?) is red and round and in line with the other red warning lights.

 

[jaxgt]

Its def my check engine light that is staying lit

 

[nota4re]

Almost all of the code readers have the capability to check "active" codes, but also pending codes. Is it possible that you can check to see if you have any pending codes?

 

[jaxgt]

Thanks Kendall. Will try that tomorrow (away today). Someone also said (might have been you in old post) that an oldish battery could throw a check engine light that can't be cleared? Not sure how old my battery is. Will check that as well. Car certainly drove fine, and zero issues starting it up a few times. Cranked perfectly. FWIW, it is always kept on a trickle charger. Speedhut gauges all seem to be working fine.

 

[jaxgt]

Update - checked - no pending or current codes. Still shows CEL that I can not clear.
I disconnected positive off battery for 15 minutes, then reconnected. Still shows light.
Ugh,,,,

 

[twobjshelbys]

How old is the battery? I had mine on a trickle charger virtually every minute I wasn't driving it for 7 years. I'd noticed a gauge every now and then wouldn't power up, but if I stopped and restarted they would come back. I finally noticed that the "charging" light never advanced to "charged". Replaced the battery and no more gauge probs. The reason I mention this is because I think the instrument panel lights are "controlled" by the same control unit...

 

[jaxgt]

Instrument lights seem fine. Have speedhuts though.

I think my DieHard battery is only 3-4 yrs old. Cant find a date readily on it. Always always on a trickle charger. Car starts right up every time too.

May try a new battery tomorrow, though not sure if / how an aging battery would throw an unclearable CEL, with no error codes available…. It is weird.

 

[2112]

My 2-1/2 y/o optima works fine if I am driving every day or have it on my smart charger.

If it sits for a week without the smart charger, it can’t start the car. Replacing it this spring.

Moral to my story? These batteries can fool you into thinking they are ok.

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