<>NTX WS6<>

LOng story short, my 02 SS was runnin perfect, never any problems until I washed it about 3 months ago and now it wont idle. After that first wash, the problem gradually went away. I fearfully washed it again last week by hand and now the problem has returned and wont go away. It will start and and instantly die, only runs if I keep my foot on the gas to idle it myself. after it warms up it will barely idle by itself, around 400 to 500 rpms. Its like the AIC is constantly seeking idle.

So after swaping out the IAC, CKP, CMP, TPS and both O2's for known good parts I gave up and took the car to the Chevy house. After a day they said the PCM "forgot" the "idle learn program". So they claimed to have fixed it by reinstalling the said program. I go to pick it up, they bring it around and it coasts into the service lane, dead. the porter gets out, i get in and the same **** is still happening. Now they say I need a new PCM...WTF? $400 extra for parts and labor. For the love of ****, someone help....

82cetuner

iTrader: (9)

shoulda just took it and had it tuned

ULTIMATEORANGESS

iTrader: (4)

when youre at the mercy of a repair shop sometimes this happens.

LS6427

iTrader: (2)

Please tell me you didn't pay the dealership for giving the car back in the same condition.......?????

Only thing I can think of that you got wet is the PCM while hosing the car down. Otherwise, every time in rained you would have this problem. I would open the PCM up...its easy and takes a few minutes. Pop both tops off the top of the PCM...see if there's water sitting in the pin rows.

Or just take it back to the dealer.....have them fix it....go for a test drive and take it home. Then subtract that first $400 from the second bill and send them a check. Thats exactly what I would do. Its their responsibility to diagnose as well as fix.

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pmj341

Did you wash the engine?? or the car? Lt1?

LS6427

iTrader: (2)

02 SS...LSx............

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<>NTX WS6<>

Went to the chevy house this morning get my car back. Obviously declined to have them install a new PCM. Still had to pay $100 diagnostic fee and am in the same boat as when I started. I unpluged the IAC when the idle settled at 800 so it wont be seeking all the time and killing itself. With the IAC stuck in the idle position, it's actually alot more drivable than when it's connected.
Checked the PCM harness connectors for water but they were clean as a whistle and dry as a bone. Seemed sealed up quite well, so don't know how or if any water is gettin in there.
The dealership said the PCM wouldn't hold the programing they were putting in it, so that's why they wanted to throw another one in there. The car only has 55k miles on it, so I'm seriously doubting the PCM is bad. Something to do with the tune??

LS6427

iTrader: (2)

Well, PCM's do fail. Mine went last year, my 1998 original. SCREW getting it at the dealership though. I got it online for $150, then sent it to my tuner to download my (427ci's) tune. Bolted it in and all GOOD.

Dealership will probably cost $500.00 or more to put a new one in.

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My6speedZ

iTrader: (18)

I'm sure you could get one off the classifieds or craigslist. Hell even look on ebay.

Screw GM dealerships, I had to get my theftlock unlocked didn't think anything of it. Then they said it was going to be an $85 diagnostic fee. Diagnostic fee? seriously just to look at my damn headunit? I told them to shove it up their ***. Got online for about an hour and half, called a few of the GM hotlines got the code and did it for free.

This is the same dealership i bought my brand new Cobalt from!

<>NTX WS6<>

To LS6427, what Symptoms were you having when the PCM was going out? Was it a gradual fail, or did it all the sudden crap the bed?

LS6427

iTrader: (2)

I started having weird idle issues back in 2007. At COLD start-up it would idle up and down for about 1-2 minutes till is smoothed out. Then after about 2 minutes it would go away, but then every time I started it that day it would idle like crap, surging up and down again for 1-2 minutes. If I put it right into "D" after engine start to pull away without giving it a little gas it would stall. I ended up unplugging my MAF and driving it around unplugged for about a year and that helped the idling issue. My PCM simply stopped recognizing the MAF and I was told it defaulted to a speed density kind of tune. Fine with me, it ran better. Then I had a problem a couple years later where my PCM was shutting off the entire passenger side of my engine, no spark or fuel was getting to those 4 cylinders. It ended up being a friend PCM...due to a loose PCM-to-Engine block ground wire.
So my PCM died slowly. It happens all the time and people chase all kinds of other issues, when its just a 10-13 year old PCM.

When I put my new PCM in the engine ran like new again, perfect cold start idles and everything else. MAF was recognized again and working normally. Been great ever since.

I did pop the tops of the PCM off to take a look.....and a few pins had burn marks on them....you can clearly see the top left row is burned up the entire length of the row. The other 3 rows looked perfectly clean. IIRC it was mainly #43 pin, which I think is the MAF pin. You can see it in the pictures. When I touched that pin, it fell right over and bent.

PCM's can fry slowly, no question about it, and not just all of a sudden...they can screw with you....

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LeanPocket

iTrader: (6)

this is correct .. if it IS the pcm.. do what he said, its easier than you think ls1tech gots yo back!

<>NTX WS6<>

Well, my symptoms have all cleared up again. It idles just fine on a cold start up and purrs like a cat during daily driving. Now I'm just worried that all this **** is gonna start over again if I wash my car or if it gets rained on, and how LS6427 decribed the way his PCM was acting before it went.
I did pull out my PCM and took a look at the pins, and they didnt look anything like those though. Not a speck of dust was in those pin valleys.
Also checked to make sure the connections from the PCM to the IAC, TPS and O2's were good, only bout 2-4 ohms between all of them. Pcm ground connection was same as well.
Wish I as able to post here with an answer to what the problem was/is cause I'm sure there are others that were, or are dealing with the same crap.

jam01

first, stop washing the engine bay, two, if you decide to try and actually diagnose problem wash one side at a time could be a bad weather pack connection. if turns out to be an ecm, gm parts direct has them for $205.