Dealer replaces PCM, van goes crazy

LanceBP

Junior Member
Joined
May 22, 2022
Posts
1
Reaction score
0
Location
Arizona
Ram Year
1999
Engine
5.9L
1999 Ram 1500 5.9L Sherrod conversion van with 75,000 original miles.

I was getting "Check Engine" and code P0753, something about Solenoid A that controls the lower gears. After a day of diagnosis, the Dodge dealer said I needed a new PCM (Powertrain Control Module).

Driving home after the PCM replacement, I discovered I no longer had cruise control. Otherwise the van ran extremely well on the 60-mile trip home.

Two days later, I took the van on an 8-mile jaunt to the park. Going there, no problem. Still no cruise control, but it ran great.

Coming home, all hell immediately broke loose. The van would go no faster than 30, then 20, then 15. Depressing the gas pedal seemed to have no effect. After 300-400 yards, it would simply start slowing down to 0. I would pull to the side, turn it off, restart it, and get another 300-400 yards of this fun. Several times it made a bizarre noise resembling a backfire. I limped home with the emergency flashers on, but it was frightening - twice it just stopped in the middle of busy intersections.

It was as though the entire fuel system had gone insane. I assume this must be PCM-related as well. Can someone more mechanically inclined than I am confirm this? I know the PCM must be programmed to the specific VIN; could the fact that this is a Sherrod conversion van be the culprit? Mechanically, it seems like a pretty standard Ram 1500.

Thanks in advance.
 

Gommer

Junior Member
Joined
May 16, 2020
Posts
20
Reaction score
8
Location
Rogers, AR
Ram Year
2020 1500, 2018 2500
Engine
5.7 and 6.7
Man, that's really a tough call. Back in the late 90's these things didn't have the controls on them that they do today. There's no telling how deep in the rabbit hole Sherrod went in customizing the thing.

I think I'd try calling them and seeing if the vehicle has something specific that would prevent you from using a factory PCM replacement. If not, I'd be looking to the person/dealer that did the work to explain the issues you were having.

In the end, though, with a 20+ year old vehicle with computer issues it's real easy to spend more money fixing it than the whole vehicle is worth. You could always give it a shot to buy a new PCM and replace it yourself. Usually the PCM is something you can replace very easily.
 

pacofortacos

Senior Member
Joined
Apr 18, 2017
Posts
2,589
Reaction score
2,877
Ram Year
2016
Engine
5.7
Could be a cam or crank sensor on the way out, bad coil - they were known to fail, bad cap and rotor, wiring issue, etc.
Could even be the PCM, though the original PCM's rarely failed. Could even be a fuel filter or pump.

You need a good scanner and someone that understands the system to accurately troubleshoot it.
Also need to try to determine if it is spark or fuel related, unfortunately, your symptoms can be the result of many things causing them.

The systems are very similar to the hemi system of today at it's core.

I doubt it has anything to do with the conversion, unless you have a bad ground connection that needs repaired - an unfortunately a bad ground can cause what you describe.
 

Daw14

Senior Member
Joined
Nov 29, 2017
Posts
1,198
Reaction score
941
Ram Year
2014
Engine
5.7 hemi
Clogged cat ? Maybe . Could be anything, corrosion on electric,grounds.
 
Top