Here's the little issue I've been having...

When the truck fully warms up and I'm running around town, the tranny won't downshift to 1st gear when I come to a complete stop. It'll start out in 2nd gear and as soon as I give it a little throttle to get moving from a red light, it'll downshift to 1st and everything would work fine after that. But at every stop it starts out in 2nd until I throttle it.

I took it to a tranny shop. He thought it was a governor transducer or something. But after he checked everything, it was all ok. He said he pulled code p1389, which has to do with the ASD relay or PCM not sending a signal.

Right now I swapped the ASD relay with the starter relay since they're the same and it still does it. So I don't think it's the relay. Could I have a bad PCM? What could cause these tranny issues?

Could a bad ground cause the PCM to act up like this?

Any other suggestions/ideas??

My truck was built Oct. 1995 and has the 47RE tranny. The TC lockup switch does not work for my particular build date. Just some info in case it helps any.

Thanks!

 

Could be a bad ground, could be the PCM. You need to get a power distribution chart from a FSM and see what that particular circut entails. Go to a local auto shop you are familiar with and ask them if they will print you out a flow chart for that code. It will tell you step by step how to pinpoint the problem.