A4 Lemon

Howdy! New member.
I have a P2181 and need to figure this out quick. I need to get smogged for registration and Im already a month late.
If I start up and get straight on the freeway, my engine will never reach operating temp. If I'm stuck in traffic, it will. For a couple weeks, it actually was functioning right and the CEL went off, but it came back. Sounds like a thermostat is stuck open, and/or the high speed fans coming on when they shouldn't. I also heard there are 2 thermostats.
Thoughts?

snagitseven

A 3 second Google search brought up several sites with the code description.
Here's one:
P2181 Cooling System Performance DTC

Kris Hansen

If the engine isn't warming up, the thermostat is likely stuck open, or the spring is weak, allowing it to open early. The fans alone won't cause an engine with a properly functioning thermosat to run cool.

You don't mention which engine you have, but there is only one thermostat on all of them.

A4 Lemon

Thanks guys. I did the thermostat swap 2 weeks ago. Can't believe how they molded an entire structure around a 2 dollar thermostat, but it went by without a hitch using a DIY from Audizine