2000 Grand Prix PCM Communication Issue

[xlarshn]

I'm having an issue (several at the moment) with my 2000 Grand Prix GT (3.8L N/A VIN K). The car has approximately 107,000 miles on it, all of which have been relatively well maintained. I have owned the car since 36,000 miles. Within the last 3,000 miles the car has had both O2 sensors replaced, spark plugs, spark plug wires, and catalytic converter. Example maintance (also within the last 5,000 miles) includes new front control arm bushings, rack and pinion, outer tie rods, tires, brakes and rotors, front sway bar / bushings, sway bar end links, headlight housings, wheel bearings, and MAF.

Here recently the car has started shuttering while going up a hill when the transmission is in overdrive. If the car is given enough gas to kick the transmission down into the next gear it will then subside. I've had suggestions that this maybe the transmission / torque converter going out but have also been told that it may be a motor performance issue (i.e. needing a tune up), which I did.

But most recently (within the last couple of days) the car posted a SES light / DTC Code. I went to hook up my father's Snap-On Solus scanner to see what the code was only to be presented with a communication error. The scan tool says it can't communicate with the PCM module. I checked the DTC connector for power which was good. I then also checked to make sure that the scan tool connector was making good contact with the DTC connector. I also tried using the cheap scan tools available at both Oriellys and Advance Auto Parts, none of which could communicate with the PCM. So is this indicative of a failing PCM, or are there more common failures regarding this communication problem that I can check. Any and all help is much appreciated. It is really frustrating to try to stay on top of vehicle maintenance when you can't even figure out what the computer thinks is wrong. I would be extremely appreciative if there is anyone relatively close to my location (Cedar Rapids, Iowa) with a scan tool that would be willing to give it a try.

Kind Regards
- - Mike

[doctorhrdware]

There might be a grounding issue or may be a wiring problem to the pcm from the scanner port to the pcm?

[BNaylor]

Are you sure you checked the right pin or contact at the ALDL port for power where you connect the scan tool? If it is an issue where the scan tool isn't getting any power then check the cigarette lighter fuse. If thats good then remove and re-tighten the PCM module 80 pin connectors. Also look behind the ALDL port for any broken or damaged wiring.


And welcome to AF.

[tblake]

On the shudder issue in overdrive, did it start immediatly after the tune up?

What brand plugs and wires did you go with?