2003 Envoy - Should I Replace Powertrain Control Module

[fwtraveler]

I have a 2003 Envoy that has 87,000 miles on it. I haven't had any problems with it up until now. I have had all scheduled maintenance performed at the same dealership.
The Service Engine Soon Light has come on and gone off at random intervals throughout the four+years.

About a month ago, I left my Ipod plugged in to charge it and it completely drained the battery. We were able to jump it to get it going, but the Service Engine Soon light has been on ever since. I took the car to the same dealer and was told there are 57 error codes, so there must be a problem with the Powertrain Control Module, which will be $900 to replace. The car is running fine.

I never understood that Service Engine Soon meant anything other than take it in to have the scheduled maintenance done as soon as possible (I'm a girl). If the light was on when I took it in, it was off when I picked it up. Apparently, the dealer never scoped it at all, but is now blaming it on me. The warranty on the module is 8 years, 80,000 miles and I'm at 87,000 miles.

My question is, should I spend the money to have this replaced, should I take it somewhere besides a dealer, and will it be OK to just leave the light on now?

Thank you very much for any help.

[brightbay]

No, do not replace the PCM.
there is nothing wrong with the PCM, the reason you have so many codes is because all the modules lost power when the battery went dead, what you have is a whole bunch of ( U codes) loss of communication.
The check engine light is designed to warn you of an emission related problem with your truck,
if the dealer did not clear the codes, take it somewhere and have them clear the codes, you need to know what code comes back and sets the light.
usually you will have 1 code stored.If the dealer cleared the codes and the light is now on again, you need to have it scanned.
And to answer the last part of your question, NO you shouldn't be driving permenantly with the light on because you're not going to know if something else is going wrong because the light is already on.

[fwtraveler]

Thank you very much for your help. I have another question just to try to educate myself. Why would the Service Engine Soon light have come on for a week or two and then gone off with no intervention on my part for all these years? It seems like it happened way to often to be an emissions problem. Could it be defective?

[brightbay]

the PCM constantly runs diagnostic tests on various systems. certain types of tests will set the check eng.light on the first failure, (type A DTC)
other tests, the light will set after two consecative failures ( TYPE B DTC)
and the reverse is true, in that the light will turn off after the diagnostic test has run and passed on some DTC, while others, even if the test passes the light will remain lit.
I'am sorry if my explanation is a bit confusing, but I tried to explain it as best as I could, and in laymans terms.
But I still recommend having the vehicle scanned, when the light comes on so at least you know what's causing the light to set.And this time it'll be just one code stored.

good luck