I recently cleaned the TB and replaced the 3 sensors on my 96 Ram 2500 5.9l. I was proud of my efforts until I started her and noticed the Check Engine light was on. It was fine before my tune-up. I pulled the codes and got a 24 indicating the TPS was out of range. I double-checked its' installation and confirmed it was installed correctly. Investigating further, I pulled the the TPS harness and got 12v across the outside terminals which is good but noticed that I was also getting 12v from the center computer lead which is bad - apparently it is suppose to vary from 2.5 to 4.8v. I assume that is what is causing my Check Engine light and code 24.

My manual says this means the PCM is "probably" bad. Does this make sense??? Since the PCM is an expensive, non-returnable part I wanted to check with the experts from the board first. It also seems to be a strange coincidence that this would happen right after I replaced all these sensors. Could it be something else?

On a side note, is it okay to use my Ram for a few short trips with this problem? I have a few errands that are already behind....

Thanks for the help!

 

Try a new TPS sensor. Our trucks are picky. Get a good one or from the dealer.

 

I tried replacing the newly installed TPS with the original (i.e., pre-fault code) one but still had the same problem.

When I unplug the TPS connector from the sensor does it make sense that I am getting 5v on the power feed (violet white) AND the PCM signal feed (orange blue) wires? My understanding is that this center signal feed wire communicates the throttle position to the PCM so why does it show 5v at the connector even when it is disconnected from the TPS??? I would think it should show no voltage until it is connected and feed from the TPS sensor.

 

That shouldn't be happening, you have a short somewhere.

 

I didn't think that should happen. Guess its time for a new PCM. I've heard that these tend to corrode and fail over time.. Guess it was just a coincidence that it failed at the same time....

Thx!