Check engine light back on after PCM replacement

The check engine light came on on my 2007 Chrysler Aspen (5.7L hemi gasoline engine). Two transmission shops indicated that the PCM was bad. The dealer where I bought the car said it was ‘shift solenoid A’ malfunction. Anyway, I ordered a replacement PCM and installed it myself. Pretty sure it is remanufactured, but that is to be expected for the age of the car. So the light did go off but then came back on after a few miles. The transmission is still in the second gear mode and does not shift. I am guessing (but really asking) for advice: it could be the transmission solenoids? Those have to be replaced all at once since the part comes with all of them, as I understand it. What should I have the shop look for besides that? I do want to try and keep the car another year if I can, but I realize I may be playing ‘whack-a-mole’ with this. anyway, thanks for any advice


Tell the shop what you are experiencing. Tell them about swapped the PCM yourself and where you bought it. Don’t tell them you did it yourself, although they will likely figure that out themselves. Ask them to diagnose it. Don’t try telling them what is wrong. Expect to pay for the diagnosis.

Tell them you want the shop to do the work, you are not going to do it yourself. Why did I write that? The shop will take more care in the diagnosis because they will have to stand behind it.


Why did you go with a PCM instead of taking care of the solenoid problem? I’d bet actually fixing the problem would have been the best idea!


Two separate transmission shops told me that the PCM was bad. One of the shops tested all of the transmission solenoids and told me they were functioning properly. It was, of course, a gamble, and I knew it was, but yes by process of elimination it may be the solenoids. I’m not an expert on this, so thanks for the advice.

It sounds like you are on the right track, but there’s more stuff wrong that needs some more shop diagnostic time is all. There are more possibilities why a transmission solenoid doesn’t seem to work correctly than either a faulty solenoid or a faulty PCM. Just a forewarning: This could soon become expensive.

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That is usually a performance fault, meaning the computer did not see a mechanical reaction when the solenoid was actuated. Probably not the solenoid at fault but the circuit it supplies fluid to; drum or accumulator seals leaking, clutches slipping.

A clutch volume index test might provide an indication of where the problem is.

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Thank you, that is an interesting point. Sometimes in fact the car does start out in first gear but then quickly goes into the default mode, second gear, engine light on the whole time. I can add that to the list of things they should look at.
Certainly walking a fine line here on wanting to get it fixed and knowing how expensive it might be.

That is definitely the dilemma; how much to sink in to the repair. New and used cars are still so expensive. I still like having the big engine for things I need to tow, but, again, the potential expense! I’m sure we have all been there. Thanks

Hey I got the same problem on my ram 1500 2006, I did replace the PCM, it resolve the problem for 4 days then it get back. I wonder what was your finaly your problem ?!

This is what happened to me with the 2007 Aspen:

I replaced the PCM and the engine light was still on.

Same error code.

I ended up having the transmission valve body replaced. One of the solenoids was bad, but they all come in a pack so you have to replace the whole thing!

That fixed the transmission issue for me. Has worked since then.
As an aside, another error code popped up after all that but was something completely different (emissions component).

All that just to get the car through state emissions! But I still like the car :slightly_smiling_face:

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I expect what happened is the error code got erased from PCM memory as a result of replacing the PCM. But the replacement PCM detected the same transmission problem after 4 days of driving, so it turned the error code back on.

The transmission is instructed to do something, then the PCM verifies it actually does it. If it doesn’t, the error code results. Replacing the PCM isn’t going to solve that sort of problem. Repairing the transmission fault is what fixes it.

Thanks for your opinion ! What i didn’t understand is why the check engine light didn’t appear.

When you said above “[replacing pcm] resolve the problem for 4 days then it get back” did you mean the check engine light re-appeared? If not, suggest to explain what actually happened, in time sequence, after you replaced the pcm.