Hi Everyone,

Was looking for some help/insight...I have a 2006 Audi A4 (2.0T-Quattro) with 89,000 miles. I received a check engine light on Saturday, while driving down the highway. I had it checked at Autozone and they stated it was a P-2181 fault code or Cooling system performance issue. I did add Coolant two days prior as I was taking a trip. The car is not overheating at all, I drove over 150 miles with the check engine light on. I replaced the actual Fill Cap yesterday as I was thinking potentially not making a good seal, and once again checked the coolant level, theres max coolant but I still have the Check engine light on. I don't think its the radiator, waterpump or thermostat as i'm sure it would have overheated...so I am thinking it's the CTS Sensor...has anyone else had this issue. Thanks for your help.

 

You either have a bad thermostat (staying open too long) or a bad CTS.

 

Thank You..I changed the CTS last night...and that fixed the problem. Not the easiest item to replace (Mostly done blind or with a mirror) and found out that there are two different CTS's (2 pin connector (Grey) and a 4 pin connector (green). Mine was the 2 pin connector...thanks again.

 

did the code end up coming back? most people dealing with this code end up having to go further than the sensor. I'm asking because I have the same code coming up. The CEL goes away in warm weather (in TX, about 8-9 months out of the year) and comes back up when the weather cools down around freezing.

 

sounds like your problem is the thermostat

 

Hi Ryan,

Does replacing CTS sensor work in long term? I am having the same code on the same model.

Thanks.

 

I just had the check engine light and it had a P2181 code on my 06 A4 2.0L. My temp gauge was reading up to the 12:00 position, so I guessed that it was the coolant temp sensor and not the T-stat. The sensor was a PITA to see unless I used a mirror, but it was super easy to replace. I then disconnected the battery for 5 minutes to reset the check engine light. The traction control light will come on (as part of the battery being disconnected), but goes off after driving it for a few seconds. Thanks to those who started and responded to this thread, I wouldn't have been able to fix this without your help.

 

I have an 08 TT with the same fault code is it the Thermostat or the CTS any help?