srf506

I have 2001 996 TT with 25,000 miles. This weekend we cranked it up and when we shifted the 6-speed into reverse the car wouldn't move backwards and acted like it was still in neutral. Checked to be sure everythiung was as it was supposed to be. Re-engaged reverse and the car acted normally. The car drove normally for the sixty mile trip. As we were idling in the parking lot the CEL came on and has been on ever since, even though the car is running fine. We had washed it the night before, but that shouldn't be an issue. Haven't read codes yet, but any thoughts on what's going on?