All:

I got this code and atemdpted to t=replce the sensors first. My problem was the temperature gauge was not working properly, however the heat is working properly and the car is not overheating.

I replaced one of the sensors the 06A-919-510-A however the tech at the Audi dealership said the one they susually replace is the 059-919-510-A. The problem I have right now is where is it located in my car (2.0T).

The data available at the delaership sucks too, it just from the 2.0T schematic to the 1.8T schematic like if they were the same. The 1.8T shows both sensors but the 2.0T is not clear on that.

The sensor I changed deals with the heat inside the car, but not with the gauge. From what I've read the next step if the sensors don't fix it is the thermostat.

Any help in locating the other temperature sensor is greatly appreciated.

 

Hopefully that helps.

When I had this code come up, I replaced that sensor first. Didn't fix the code.
Then I had my timing belt service done because it includes the water pump, and I was due for the service anyway. Didn't fix the code.
Then I read somewhere that a missing belly pan could cause this because when outside temp is cold and there's no belly pan, then the cold air rushes into the engine bay throwing off the sensors. I had lost my belly pan the previous winter due to it cracking off from ice buildup. Got a new belly pan and installed it. Helped the temp guage a bit, but still the code came back.
Finally I decided to tackle the thermostat myself. Well sure enough it was stuck. New thermostat, car gets up to operating temp quickly and stays there. Haven't gotten the code since.

So, I would certainly start with the coolant temp sensor since it's cheap and relatively easy to replace. But if it doesn't fix it, you see what I had to go through. If you're not due for timing belt service I'd go right for the thermostat. About $100 and a couple hours of your time.

Good luck

 

its the thermostat.

2181 is cooling system malfunction fault, not coolant temp sensor.

I actually did one today

 

Thanks for the responses. I'm planning to replace the thermostat. Any recommendations about what brand to purchase? I've heard about BEHR, dbcperformance, etc.

Any help is greatly appreciated.

 

I finally received teh thermostat from bdctuning. Are there any good instructions for its replacement?

Thanks,

 

Thermostat Diagnosis/Replacement Technical Questions

 

So does the 2181 mean thermostat is not working? I have a 2008 audi TT 65K miles and had the same problem. Changed the sensor, it went away for a while and it came back. Temp gauge is not working again. You reset it and goes away for a while but comes back again.
What should i do? comments would be appreciated.
thx

 

The best thing you can do is to replace the thermostat. You can find it for about $60 and it will take you about 2 hours and a bigvjug of coolant to fix it. There is a link for work instructions for the 2.0T. That will get rid of the issue you have. Hope that helps you.

 

Yup, definitely replace the t-stat. I also tried the temp sensor first and the code went away for a little, but came back. New thermostat fixed it right up.

 

I being having the same issue on my Audi a4 quattro 2008!
light came on and the temp gauge is marking right in the middle!
code p2181..read all the comments and i still dont know what to replace!
cooling sensor or thermostats?
somebody know the part number for both?