battery light with brand new dealer battery

OK, so i have been having starting issues and even though my battery was newer it was from a chain store and I figured it didn't have enough amp hours. So I bought a new dealer battery less than an hour ago.

Long and short of it is I have a new dealer battery at 12.5 volts and with the key on but engine not started I have a check engine and battery light lit. as soon as you start the car they both go away. (alternator a ok 14.4 volts running)

there was an intermittent low voltage code but I cleared it and it hasn't returned. Now when I scan with VagCom i get no codes whatsoever.

So now I have a check engine and battery light I can't clear. It is monitoring a system that has been independently tested to be at the proper voltage.

Any ideas?

check your grounds and battery contacts.

There's nothing wrong. They are supposed to be lit when the engine isn't running.

The CEL and battery light come on before you start as part of the lamp test, to let you know the warning lights are working properly.

-Jason

I must have misread, I thought the light was staying on.

puter said:

I must have misread, I thought the light was staying on.

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You read right the check engine and battery CEL are remaining lit after all of the self tests have completed. I/E If you leave the key on 10 minutes they are still on. Battery and check engine. Once you start the car, they go off.

Checking the grounds etc. is a good idea but the problem started all of a sudden when none of those things had been changed.

I might have hooked up jumper cables to a loose battery backwards, is it possible I fried something in the ECU?

EDIT: it is quite possible the behavior is normal and I just never noticed before having these battery problems. if so, sorry for wasting everyones time. I sincerely think this is a new thing but i've been known to drop the ball before.

thanks,

Jester

how healthy is your alternator? Have it checked at autozone, they do it for free.

You installed a new battery. Have you found a way to change out the battery without disturbing the connections to the battery, because I think you could make some serious money on that technology

Well stop and think for a moment. The battery light comes on when the alt isn't working. The CEL light will remain on until the engine is running. With the engine not running the alt isn't spinning, and it's not running so the CEL will be on.

If all the idiot lights go out after the engine has started you have no problems.

puter said:

You installed a new battery. Have you found a way to change out the battery without disturbing the connections to the battery, because I think you could make some serious money on that technology

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Puter, it was doing it with a previous battery too. I thought it started all of a sudden with that battery. Putting in a new battery carefully didn't change anything. I was assuming I didn't bolt two batteries in wrong

Everyone is assuring me this behavior is normal leading me to believe I am not the most observant apple on the tree, hehe.

deadend: it shows 14.4 volts when car is running, so within spec anyway.

compu_85: well explained. That puts my mind at rest that I am just not remembering the way my car works even though i've had it since 2005.

thanks for everyones help with my silly little problem.

Jester

P.S. The battery I took out was on its last leg, would only start the car if the weather was 50+ degrees, so at least I didn't buy a new battery only because of my normal idiot lights, hehe.

jester69 said:

Long and short of it is I have a new dealer battery at 12.5 volts and with the key on but engine not started I have a check engine and battery light lit. as soon as you start the car they both go away. (alternator a ok 14.4 volts running)


So now I have a check engine and battery light I can't clear. It is monitoring a system that has been independently tested to be at the proper voltage.

Any ideas?

Click to expand...

Your battery will read about 13.5 volts after its used a while and charged up.
It lights are acting as they should as others have explained.
You ARE clearing the code when you start the engine and the alternator begins turning.