My wife's '01 Grand Prix shifts hard every once in a while, and the check engine light comes on for a short period. I checked the codes and found the following: P0420A (catalyst low efficiency) and P1811 (maximum adapt and long shift). The trans fluid is full and looks and smells clean. The cat was just replaced less than a year ago. I talked to a tech at the dealer in town and was told there is sediment in the PCS. They said the trans would have to be pulled to clean the valve body and replace the PCS. Does that sound right, or could there be something more simple with the codes I have found? Any help would be greatly appreciated. If I can get away with not pulling the trans, I would be a little happier.
Apr 9, 2006 at 1:14 AM