code 55.....on an 81...

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Dec 19, 2001 | 10:03 AM

ksems

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From: Alpharetta GA

code 55.....on an 81...

Good Day ...

"Check Engine" light came on and went off yesterday.
Checked the code and got the number "55"

which translates to oxygen sensor or faulty ECM.

My oxygen sensor was replaced a year ago...shouldnt be bad, should it?

Ive also noticed a "ping" under light acceleration.

The Haynes manual I have says that code 55 is
a faulty TPS or ECM....hmmm?

Any thoughts?
Thanks
Kevin

Dec 19, 2001 | 10:54 AM

81VETTOM

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From: Near Raleigh NC

Re: code 55.....on an 81... (ksems)

I'd go ahead and try the sensor use a GM one. I have replaced one on my 81. If that doesn't do it, ?? Is the ECM got the stock prom? :smash:

Dec 19, 2001 | 11:20 AM

ksems

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From: Alpharetta GA

Re: code 55.....on an 81... (81VETTOM)

81VETTOM,

Thanks..

I guess Oxygen sensors can go bad that quick? They are a pretty quick and cheap thing to try.

The ECM has the stock PROM...

Dec 19, 2001 | 02:36 PM

81VETTOM

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From: Near Raleigh NC

Re: code 55.....on an 81... (ksems)

I'll check in one of my manuals, I do have a GM 81 ECM manual. A rare bird for sure. I'll see if it is more descriptive. O2 sensor can go bad, especially if gas has additives and some of that reduced emission stuff I am told. It is a cheap try. You can get reman ECM's from Eklers for about $100 or so if it doesn't clear up. Disconnect one side of battery to clear computer and try once more to see if code sets, i assume you tried this already.

Dec 19, 2001 | 07:59 PM

ksems

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From: Alpharetta GA

Re: code 55.....on an 81... (ksems)

Dec 19, 2001 | 08:30 PM

Dalannex

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From: Northeast South Dakota

Re: code 55.....on an 81... (ksems)

When you have your O2 sensor out, look it over carefully. Make sure that the cage part that is the outside of the sensor is not eaten away. Look for signs of running rich. I had to go through a few O2 sensors when I was getting my rich condition taken care of. They either soot up, or completely burn up. You could also check your TPS. If you don't know how post here, I'll scan you some instructions and send them to you.

Dec 20, 2001 | 11:06 AM

ksems

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From: Alpharetta GA

Re: code 55.....on an 81... (Dalannex)

Dalannex,

thanks for the help....The O2 sensor comes out this weekend to take a look...
I would be interested in the procedure for checking the TPS as well....:)

Kevin