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Missourian 04-14-2013 03:27 AM

Help im out of ideas... Bad PCM?
Ok so my 06 manual 4banger has been having problems at idol... about a month ago it died but started right back up... then 3 weeks ago it wouldn't start. I got it to the shop they replaced the fuel pump and found that I had to wrong plugs.... (not done by me...) so then after I got it out of the shop the check engine light was on... I had em look at it and the cooling fan is flagging... they didn't help me so I brought to a different shop... they said they tested everything from relays and all that and they said everything is working so it could be the pcm... so I'm in the process of saving for one. But tonight I left the bar and I was in a drive through.... the idol dipped real low and before I could give it a little throttle it died... and now won't start again... does anyone have any idea what's going on with it? Could the bad pcm cause the fuel pump to go bad or stop the car from starting? Thanks for ur help ahead of time!

Jerry Bransford 04-14-2013 10:42 AM

You've been watching too much American Idol, you actually mean idle. :) Your engine dying could be caused by a number of things but my first suspiciion is a bad CPS (crankshaft position sensor). Mounted on the engine, the CPS is what generates the engine's master timing signal and when it starts going bad, the engine will suddenly stall.

I don't know what you mean by the "cooling fan is flagging".

Missourian 04-14-2013 01:51 PM

When the shop is hooking up the scanner to my computer, its saying that my low speed and high speed fans are not working. So when I drive they don't kick on... the shop can remotely turn them on so there isn't a short, and they did all these other tests to rule out whatever could be wrong I guess... and they said since everything else checked out then that means the pcm is bad.

JDT 04-14-2013 10:23 PM

My 05 4cyl was throwing all sorts of codes and was running bad. My fan ran constantly though. It turned out to be the PCM. Chrysler has an 8 year 80,000 mile warranty on their computers and I got mine replaced for free at the dealer. You should go check and see if you are still covered by the warranty, it'll save you a lot of money.

Missourian 04-15-2013 11:51 AM

Oh man that would be awesome lol. The shop that did the fuel pump is replacing it for free I just had to pay for the tow. But I guess what I'm really trying to figure out is if a bad pcm can cause the fuel pump to go bad. Idk how it could but that's why I'm asking cuz idk lol.

Jerry Bransford 04-15-2013 11:54 AM

The PCM controls the ASD (auto shutdown) relay which is in the fuel pump circuit... sot the PCM definitely could cause the fuel pump to be inop. The PCM checks various sensors & if it doesn't like what it sees, it can shut down the fuel system.

Missourian 04-15-2013 05:58 PM

So got the jeep back promptly... apparently the hose came off from pressure... sounds to me like this po dunk shop is worthless and they didn't put it on right.... but NOW lol when ever I push the clutch in at he speeds and coast... the car drops RPMs and dies... I love my jeep to death but she and I are about to have a talk lol

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