For the past couple of weeks, my check engine light has been on but the truck drove fine. Put a couple hundred miles on it this way, and the light would come on sporadically sometimes on sometimes off. It was a P0601-Internal PCM Failure. Trucks got 190xxx on it.

Fast forward to the beginning of this week, I get in the truck to drive and the sucker wont shift out of first. So im thinking maybe the truck is just locked down into a safe mode. Well i take it to a tranny shop to get em to look at it, and they get it to shift into 3rd at about 5K rpm's, of course they say they think its internal transmission related, that the bands are loose and tightened to their max. And that I will need a rebuild.

Take it to another tranny shop and he says that everytime hes ever seen that code show up it HAS been the computer. So i can get a re-man'd PCM for ~200 I believe, but if the computer in it is actually fine and it is the tranny then Im out the $ for the PCM.

What do you guys think? I dont quite know where to start...

 

I can't see P0601 coming from any transmission failure. What I'd do: Disconnect negative battery cable, then remove and reinstall all of the plugs on the PCM. Then check all of the body/chassis grounds in the vicinity, maybe go so far as to open them up, clean all of the stuff that's supposed to be metal to metal, and put them back. Check the connections at the battery and in the PDC. Then give 'er a go, see what happens.

Welcome to DF! It'd be helpful if you'd put the vehicle information in your profile and/or your signature, too. Good luck with the problem solving!

 

Got a question, can I just get a PCM from a junkyard as long as it is from a 5.2, 2WD w/ and auto trans? (same specs as mine)

 

Yes........but have to have it flashed to VIN.

Do what UU suggested before you spend money or chasing rabbits....

 

^ i think i disagree that it must be flashed to his VIN. no personal experience but i've heard of people trading PCM's to check whether there's was bad or not...

 

Functionally, no it does not have to be flashed, but if one lives in a place that has the severe inspection requirments, the VIN from OBDII port will not match vehicle and could be a problem at that point.

That is why when you order reconditioned unit, the need VIN and miles from odometer.