P2181 Cooling system performance. Help

Was driving home and my engine light comes on, so I go to Autozone to get the code pulled. P2181 cooling system performance. Either low engine coolant, failed radiator or water pump, or check ECT sensor.

So I check my coolant, which I also did about a week ago cleaning over my engine and it's fine. My temperature gauge on the dash also works fine. I searched up this code here on this site and on vortex, and didn't get too many results. Either that its the sensor, or most likely the thermostat. I just don't want to go digging to replace the thermostat and housing yet.

When driving, the car Seems to warm up normally, but this is only one day. When I leave for work today I will check again to see if it takes longer than normal to heat up to normal operating temp on the gauge. When driving, I did notice my gauged sits here though:

As far I know, it's always been straight up and down while driving, although it's been a lil colder outside now. I hope it's not the thermostat, so I'm going to replace the ECT sensor fist. Does this look about right to you guys?
http://kmdtuning.com/index.php?_a=viewProd&productId=1187
It's the best price I found on the OEM part. ECS has one for 8 bucks, but I don't know of the quality.

One last thing, anyone on here replace a thermostat yet? Around what part of the engine is it? I've heard the rear bottom passenger side, and I've also heard under the alternator. Is it hard? I'm good with working on cars.

Does it take a long time to warm up?

Just got back from work, and headed there and back, the car warms up normally. It takes like 6-8 mins for it to be close to normal. I'm going to clean my connector up well and probably buy a new sensor first. It still might be the thermostat though, just stuck partially open. While driving, it stays in the position like shown above, when normally it would be right in the middle. Anyone have any pics of the thermostat location or a how-to?

that flaut usally means t stat. if the rest of the coolant system pass out a t stat in. you need to remove alt and it in a plastic housing

if the vehicle warms up slowly, it would be thermostat. An ECT sensor runs your temp gauge. I wonder if by "performance" it might measure water flow/pressure/velocity. But I do not believe there is a sensor for that, nor do I see a need for the compiuter to need that value.

could also be your water pump, easiest way to check if the water pump is performing correctly, pull off the small hose going to coolant bottle, check to see for coolant flow when warmed up, have friend hold at 1k and see if flow changes, if no change, needs water pump!

An update, I cleaned the sensor and reset the code by pulling the battery about 100 miles ago, and so far the light has not come back on. However, while driving down the highway my car was already fully warmed up when the temp just dropped from the middle, to about halfway between 1/4 and 1/2. It took a few minutes, then it went back to normal. This is leading me to think it's just sticking sometimes.

Could someone let me know how much torque the thermostat housing bolts need? And the alternator bolts since I have to remove it. Thanks

Deff keeping an eye on this thread since the exact same thing is going on with me right now. I was going to make a pointment at VW but we all know how much they over charge

Mine is doing the sameee thing. I'm going pick up a sensor now really hoping this fixes my problem.

One question OP. Did your fans run longer then normal when turning "off" the car? Mine is running for about 10mins at pull speed after the car is turned off...

This code has popped up twice now on my car and I have about the same amount of miles as the OP. I want to replace the water pump and thermostat when I do the timing belt so I am hoping to be able to hold off for a while.

I had this code pop up about a week ago and then the engine light just turned off on its own. Driving to work today and it turned on again, the code is the same. As far as OP's needle not sitting right in the middle...this happens to mine as well but if i remember correctly mine used to sit perfectly in the middle when i bought it so maybe it shouldn't be leaning towards the left. I have 64,xxx miles. Please let me know how you end up fixing it.

Same code i got. W/ a vag com its easy to figure out what the problem is you need to check the temp that the code came on at

http://wiki.ross-tech.com/wiki/index.php/18613/P2181/008577

Sent from my EVO

I ended up getting just the thermostat replaced, no sensors, and the problem is gone. Was just a bad thermostat not closing all the way. My fans didn't stay on any longer than normal.

same thing is happening to me, CEL turned on two weeks ago, i didnt have my scanner so i disconected the battery, now 320 miles later (mkv is a 07 with 49k) cel is back on. and of course just in time for me to get an inspection sticker smh. is the majority of this problem the thermostat?

i Had the Same Issue. It Was My Thermostat Also. Pain To Change Too.
If You're Going To Diy, remove Intake Manifold And Clean Valves While You're There.