Coolant Temperature Sensor - 1 or 2 of them?

[irishfan]

Hey guys,

Just arrived here and am so happy to be a part of this forum and an Audi owner. I have a 2006 Audi A4 2.0T FWD. I have talked to a few people and have been getting mixed answers. I have been throwing a P2181 code and so i suspect its either the coolant temp sensor or thermostat. I replaced the grey 2pin sensor in the rear of the engine block and I am still throwing the code so i began researching replacing the thermostat. Its then that i had a few people tell me that there is another sensor that I should replace before i replace the thermostat. I was told its the green 4pin one but i have looked an audi manual i bought and looked on my car but I cannot find anything about a 2nd coolant sensor and where it would be. I was told by a local mechanic that there is on near the bottom coolant line near the front of the engine but again i dont see anything.

Does anyone know for sure if my car has 2 coolant sensors?

Thanks so much!

[Der Konig]

No, those are two different sensors revisions for the same connection, green is the new revision. If the CTS you replaced didn't fix it you need to do the tstat.

[Inked]

How much did the sensor cost you? I need to pick one up to be put in when I get my timing belt done...

[Der Konig]

They are about 20 bucks depending

http://www.europaparts.com/coolant-t...59919501a.html
http://www.europaparts.com/coolant-t...6a919501a.html

[MWP]

Chances are it's your thermostat and not a sensor. The sensor is cheap and easy so you may as well try it though.

[irishfan]

Thanks guys! Yeah i already replaced the sensor and still throwing the p2181 and my temp gauge doesnt get to half way point until i have been driving for like 40 minutes..most of the time its at the 1/4 mark.

I got it as part of a kit from ecstuning for like $80 with shipping...it came with the grey sensor, orings, clip, thermostat, bolts and g12 fluid. I am thinking of putting in the tstat myself but again getting different opiniond. I have two local guys tell me that its a pretty involved job b/c you have to take off the intake but from what I can tell is i just need to take out the alternator and then can get to the tstat...the hardest part looks to be getting the hoses off it...any thoughts?

[kegobeer]

Thanks guys! Yeah i already replaced the sensor and still throwing the p2181 and my temp gauge doesnt get to half way point until i have been driving for like 40 minutes..most of the time its at the 1/4 mark.

I got it as part of a kit from ecstuning for like $80 with shipping...it came with the grey sensor, orings, clip, thermostat, bolts and g12 fluid. I am thinking of putting in the tstat myself but again getting different opiniond. I have two local guys tell me that its a pretty involved job b/c you have to take off the intake but from what I can tell is i just need to take out the alternator and then can get to the tstat...the hardest part looks to be getting the hoses off it...any thoughts?

Sounds like those guys either don't know Audi cars, or they want to make some money off you. It's a few hoses and the alternator and that's it. It only takes about an hour. There's a guide for it - just do a bit of searching.