Thread: 06 Grand Prix GXP - Service Stability System - Reduced Engine Power - P0606 C0240

Hi All,

I'm having a bit of a problem with my 06 GXP. Randomly, upon startup, i got the Service Stability System / Reduce engine power message on the DIC. When the message is up the car drives like a dog. I replaced both front wheel bearings (both had a ton of play) but it did not fix the problem. I get 2 codes on the scanner (see below) but nothing too helpful. Anyone have suggestions? More info is below.

-Only happens on start up. Never while I'm driving.
-It is completely random.
-I get codes P0606 Internal Processor Fault. C0240 PCM Traction Control Not allowed.
-The airbag light flashes 4 times after startup.
-The check engine light is on sometimes, sometimes not. It is on sometimes when the power is reduced, sometimes not.
-The vehicle has 75K miles on it.
-The scanner shows the speed sensors appear to be working (and match each others speed). I did notice they say 2 mph when I'm standing still.

Sounds like the PCM has a internal issue with the P0606 code.

Originally Posted by Fivefingerdeathpunch

Sounds like the PCM has a internal issue with the P0606 code.

Are you thinking a new PCM would be in order, or that this one would need a re-flash or software update?

I know the GM dealer wants $80 to just scan into the car. Not 100% sure what my next step should be. If i get a new (used) PCM, isn't there someone on here who could set it up for me? I remember someone used to do the tuning, but i can't remember who.

In case anyone stumbles across this, i purchased a used (re-flashed) PCM on eBay. It costs $200 and i did not have to send the core back. It fixed the problem 100%

Important: You will have to do a re-learn of the security system. It is extremely easy but takes a lot of waiting (about 30 minutes). ALSO you may have to do a crankcase re-learn. I'm not sure but i did it anyway. It can be done by anyone with a more advanced scanning tool.