Cadillac DeVille Problems

Powertrain Control Module Electrical Ground Fault on Cadillac DeVille

Problem Description and Possible Solution

This powertrain control module (PCM) may develop a fault with its electrical ground location at the front of the engine block near the starter motor.

(22 people reported this problem)

Cadillac DeVille Vehicles With This Problem

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Average mileage: 117,623 (54,560–199,999)
Engine affected: 4.9L V8
9 model years affected: 1990, 1991, 1992, 1993, more1994, 1995, 2000, 2001, 2005
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Viewing 1-6 of 6 comments
car missed at idle then shutting down while driving down highway. took car to 2 dealerships plugs,wires,cap and rotor button replaced. 3 cats put on an egr o2 sensor new battery fuel injectors and all this work I still had same problem. solution; I was ready to scrap the car then an old mechanic that knew nothing about computers told me to check all my grounds. I thought he was crazy but I had nothing to loose. ran all grounds down cleaned them and guess what,, car runs like new I ask him how he knew that he just smiled goes to show computers cant beat wisdom made me feel pretty stupid. p.s. don't forget the ground down by the starter that was my problem the whole time
Vehicle at first didn't start up right away then after about 2weeks started fine until maybe a month later the dash displayed various service codes and dash start blinking crazy one day cut car off wouldn't start at all towed to dealer who informed me the PCU had to b replaced $1500
My ground cable broke and shut down the whole vehicke. Took a week to notice the cable then it has to be welded in ordered to fix the problem will causr the speed odmeter to go haywire an sometimes not allow the vehicle to start
I have same problem with code C1298 code reader said powertrain module serial data link malfunction . It also said class 2 .I have not yet investigated this yet . Because my other car is being repaired . I find it strange I have 2 totally different cars both have ABS and Traction control lights on. If anyone can answer this question I would be grateful. I have other things wrong with cadillac and I definitely don't want to over pay again for all the codes and repairs. This just all happened at 59,000 miles.