It all started with killing the engine at a stop sign; I was in a hurry and let the clutch out too fast. Check engine light immediately came on for a day, thought it was a loose gas cap which I tightened, light went off later that day. Then it came on again the next day.

When starting the engine cold, the cooling fans came on full and stayed on until the engine temperatue was at the quarter mark on the gauge until shutting off. In addition, when starting the engine cold, normally the revs hold at around 1100 for a few minutes, but was now always idling at 850 after a cold start.

Taking the car into Schucks to borrow their OBD2 reader, one code was pulled - p3081 with no description. So hedging my bets, I ordered a G62 engine coolant temperature sensor (ECT).

Followed the DIY on-line ( http://www.audiworld.com/tech/eng66.shtml ), boy was that a PITA. Seemed much more difficult than when I changed the timing belt a month back. It took me about an hour+ to do.

Part of the problem was that the plastic retaining clip holding in the sensor was plugged in from the front of the car with the tines facing rearward. I ended up ripping the plastic handle off a screwdriver so I could get the slim 9 inch metal piece straight down there to pry the retaining clip off. Upon re-installation, I put the clip back on from the firewall side with the tines facing the front of the car so it's an easier removal next time.

As a tip, your left arm can fit above the turbo up into the back of the engine to get to the part easier. You've got to lie on the engine and bury your arm to the tricep to get there.

Replacing the sensor, the fans stopped running full bore upon a cold start and the RPM's were back up. But the check engine light was still on after multiple trips around town. So back to schucks I went to reset the light.

Before the reset, I read the code again. Gone was the P3081, a new P0118 had taken it's place. Resetting the code, the CEL hasn't come back on yet.

Have fun.