Possible PCM Problems
 

My truck has lost overdrive and the grid heater. Some of the guys suggested disconnecting the PCM and cleaning the connection, which I have done, but to no avail. I disconnected it for over an hour, cleaned up the connections, which were not bad to start with, and reinstalled it.

The original series of events with the truck were: (not sure if all matter or not, but here we go):
1. antilock light came on for several days before #2.
2. Warm, moist weather went to -30 degrees in less than 24 hrs.
3. grid heater out-no wait to start light or grid heater "pop". Overdrive also stopped at the same time. Antilock light now comes on and goes out at start up as normal.

I did not remove the PCM itself. I don't know if it's grounded to the body, or internally grounded. Should I remove it and clean where it is attached?

Has anyone experienced this as well? I am hoping to check everything I can before forking out the bucks for a new PCM. Any help would be greatly appreciated.

The ABS is controlled by a different box (behind the glove compartment).

Do you still get a bulb check on the water in fuel light?

The PCM has several grounds leads, it's not case grounded.

Thanks for the response wanna. I don't get the bulb check on the water in fuel at this point. This went at the same time. Where are the ground leads located? I don't know if that's the problem, but I'll sure try to clean them before spending on the PCM. How often do you come across a blown PCM though? I haven't read about it on the forum to my knowledge.

Does anyone know where the PCM grounds? I have an electrical nightmare of previous owner mods, if you want to call it that, so any guidance where to start would be most welcome.

Check the cummins indcater block in the cab, where the wait to start light and water fuel light is some time's the indcater block burns up. It will make all kinds of lights come an go. Take loose the inter dash panel and three screws hold it on some times u can see blacken places when the block shorts. Good luck.

Hi,

When mine did all of that , I found a broken fusible link. That is a really common problem.
Mike

Did your overdrive malfunction as well? Where did you find the fusable link responsible? Thanks fir the replys guys, I'm hoping I can track this problem down.

fusible links are on the left fenderliner, right in front of the left hood spring. If you search the forums for "fusible link" you will find some threads about them. there is one near the top right now called "fusible link abatement" that has some pictures of the FL block.

I just replaced both fuse block and pcm on my 09 ram 3500 6.7 and i got all my power back except for it to get it to start how do o reflash

Well first thing welcome to DTR. Second thing it's best to not drag up an 11 year old thread to ask a question about your truck. Third thing would be to post your question in the correct forum. This is the 1st Gen forum for 89-93 trucks. You want the 3rd Gen forum for your 09.