One problem related to automatic transmission control module has been reported for the 2000 Cadillac Deville. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2000 Cadillac Deville based on all problems reported for the 2000 Deville.
When cold, upon starting engine and shifting into either reverse or drive, the car abruptly jolts and vibrates. Problem originally would occur when car was cold and gas tank was less than half full. As the weeks/miles passed, the jolt problem began to occur more frequently, regardless of the amount of gas in the tank. Initially, jolt problem only occurred when car was cold. However, jolt problem now occurs on all startups, regardless of a cold or warm start. Car was taken to dealership early on, when problem was more prevalent with cold starts only. Dealership contacted Cadillac and reported the problem. Car owner was advised that a "technical fix was in the works" for the pcm module (the apparent culprit was related to emissions), promised available in 60-90 days. After 90 days, car was again taken to dealership for the same jolt problem, only now it occurs all the time. Dealership contends there is no fix, because the jolt is not a problem, but a feature - that one must wait 45-60 seconds after starting engine to put the car in gear, so that the car has a chance to warm up. This is not the solution, as the problem occurs when the car is warm as well. Major concern is that the jolt problem has gradually worsened over time/miles, and owner is unsure of the detrimental effect the jolt has on the engine or transmission. Found a comparable customer complaint at NHTSA website regarding sudden acceleration (jolt) and the need to warm up for at least 30 seconds, which appears to corroborate that a known problem exists.