Hello, Newbe here and I have my first question here about a problem with my a6. I have a code po118 (ect sensor). So I went to audi dealer today and bought one and the o-ring they said I needed. Well I can't seem to find where it goes? Is it the one in the lower radiator hose? Is there one some where else. The temp gauge in the dash seems to work good (never goes over half way) the coolant is right at the max line on the reservoir. Is there somthing else that would cause this code? Thanks!!!

 

by the way, in 2008 Audi issued a warranty extension 10yrs/100k miles for A6's to replace ECT sensors I think. Look into it.

 

CTS is located behind the motor on top of coolant cross over pipe. The old sensor has black head with 3 or 4 wiring going into it. You need to pull out the clip and replace the o-ring and the sensor. Make sure not to break the plastic clip and seat the sensor correctly.

BTW, replace the sensor when the car is completely cold. Relieve the pressure by opening the coolant reservoir and closing the cap back on.

 

Thanks hxgaser, I got it done so time will tell.