PCM Question
 

Hey guys

The "service engine soon" light is on in my 96. It's apparently from "low activity" on the bank 2, 1st O2 sensor. I paid a shop to tell me that. That said it's either a bad O2 sensor, bad wiring or a failing PCM. Car runs fine btw.

I replaced the sensor and the light stays on.

Research I've done does indicate that a bad PCM can throw "bad codes".

I see some PCM's for sale on Ebay and the seller can program the PCM to my car's VIN number.

Thoughts on my doing that? Would save me some $$$ buying a preprogrammed PCM off Ebay for like $90 rather than my having the shop swap it out for around $600.

Thoughts? I'm getting ready to sell the car so any input would be appreciated! :)

Re: PCM Question
 

Do you remember the exact Pxxxx number for the code? You can typically get auto parts stores to pull OBD-2 codes for free.

PCM failures are very rare.

Re: PCM Question
 

Po154

Re: PCM Question
 

How many times have you driven the car since you replaced the O2 sensor?

The PCM will not turn off the SES light until the third consecutive trip in which the diagnostic has been run and passed. The code itself will stay in "history" until 40 consecutive warm-up cycles have occurred without a fault.

Re: PCM Question
 

Really? Wow. Well, the kid at Autozone didn't tell me that. He said if the light comes on after I put the new sensor it in then there's something else wrong. Bad PCM, bad wiring.

I also disconnected the battery and let it sit for about 15 minutes hoping to reset the PCM.

I put the old sensor back in and returned what I bought. So, your recommendation is for me to put a new one back in and keep in there for a while?

Thanks for your input. I really appreciate it! :cool:

Re: PCM Question
 

The kid at Auto Zone probably didn't refer to the 1996 factory service manual :D.

Did you have it scanned again to confirm it was still the same code?

Re: PCM Question
 

I will swap it out again and have it scanned again if it stays on again.

Re: PCM Question
 

Please don't rely on anyone at Autozone for diagnostic advice.

Re: PCM Question
 

One thing I failed to mention because I didn't think it mattered is that the engine in my 96 is a freshly installed engine from a 1998 Camaro. The PCM is the PCM original to my car - it's not the PCM that came with the engine.

Could this be the culprit as to why I'm getting that code about the O2 sensor?

Car runs great otherwise. Really good.