Hello, well, I'm fixing issues on this truck, slowly but surely. So... Truck shifts fine 1 to 2, 2 to 3 but 3 to OD has an issue. It will shift into OD for a short period, then back out and back to third and TC will lock and unlock, not staying in OD for long. It is throwing TPS voltage code, so I started investigating. When I unplug the TPS connector and checked voltage with key on, I get 5v at the purple wire, ground is good, but I'm getting around 4.5v on the orange and white signal wire. I believe this is not correct and believe the signal wire should be reading 0. When I plug the connector back in, and test voltage on signal wire, it read somewhere around .2 to .6v kind of jumpy. When I open throttle, I get reading of around 1.5v. I know this not correct so tried adjusting TPS and sliding bushings out of holes, not getting more than around 1v with throttle closed, more like .8 or .9, again kinda jumpy. Why does the signal wire give me 4.5v when unplugged from tps, and when plugged back in and test I get nowhere near 4.5v but a low reading of .2, .3, .4, or around there???? I've traced wires to the pcm, look fine. Could the pcm actually be bad?? I've read about this same problem before, and a guy plugged in a new pcm and still had 4.5v on the signal wire at tps, but never seeing any true answers on forums. I've seen this exact problem on forums, but seems all discussions on this issue petered out with no update. I really don't suspect a bad tps either, but could be wrong. I've seen a bad tps before and wasn't these exact symptoms. Now, the throttle linkage and cables were replaced by previous owner, might be out of adjustment too. I notice a voltage change while testing signal wire when just simply wiggling the linkage directly above the tps. Not sure if this can be related,, but probably is. Any and all help on this will be greatly appreciated. 4.5v on signal wire when unplugged?? ***? 😥😥😥😥😥😥

 

Same problem. What is the solution? Please?

 

As I recall, when I had the same problem with my '94 12v, changing the TPS resolved the issue.

 

Currently dealing with the same issue. Tranny just rebuilt, and new TPS. I have been tracing all of my ground wires, checking condition and cleaning connections. Including negative terminals on batteries. I have been researching as much as possible and have read possible ground wires and or alternator issues. Some install a noise filter on the TPS line as well. Some guys I guess have decided to install a POT in lieu of the TPS and have had good results. I have improved my shifting and lowered the frequency of it happening, but it is still dropping out of OD.
Hope that's new info to try.