janserce79

Maybe I should send my gauges for rebuild? Can a faulty water tem gauge trigger the code?

emjayem

This pesky code has come to me today in the form of an 04 audi A8. The car came in with the engine fan on High and the temp gauge full cold. heat from heater was good. cleared the code and everything went back to normal! fan turned down and guage read engine temp, which still read a bit low. I am in the middle of diag right now so I'll post back what I find.

The actual P3081 code means this according to VAGCOM.

"engine temp too low, implausible signal-MIL on

hope this helps

socalclimber

I get the similar info in eBahn repair manual for 2003 A6 2.7 w/ BEL engine:

SAE VAG Description
----- ----- -----------
P3081 19537 Engine temperature too low

Note: Let engine warm up; coolant temperature must be at least 50 C (122 F), advance scan tool to Diagnostic mode 1: Check measured values; PID 5, Coolant temperature.

janserce79

yeah, my temp gauge is cold all the time now. At least I know now it's related to the code. Thanks guys for the info. Now the question is: what's next....Do you have any info on troubleshooting the code? Dealer told me that this engine has 2 temperature sensors. I replaced one with TB job. Maybe I should change the other one? Thanks.

emjayem

the temp sensor on the rear of the engine is the problem one. is that what you replaced? its kind of a pain to get to.

janserce79

No, I replaced the bottom radiator sensor when doing timing belt(lots of posts were pointing to that one). Are you talking about "engine temperature sender for engine control module (G62)"? You may be right. If it is for ecm that explains the check engine light & code. I'll try to find some more info about this sender. I hate changing parts and not knowing why. Do you have more info or experience with this sender? Thanks again!

emjayem

yes (G62) is the one. I can almost guarantee that this is your prob. I have replaced dozens of them on everything from jettas to A8's. It is the sensor that provides an input to the ecm and cluster module. it is a 4 wire connector and is usually green.It sits just below the throttle body on the back of the engine. It is kind of a pain to get at, but it will fix your prob.

HINT: When you pull out the horseshoe clip/retainer for the sensor it is a bit tricky, you'll have to shimmy it between the sensor and the block, a long screwdriver works well for this. When you re-install the clip, you can install it backwards, for much easier install.

HINT#2: When installing new sensor w/ new o-ring apply just a bit of vaseline on the o-ring so it will slide right in. make sure you get it pushed in all the way or you will have a leak.

Hope this helps!

emjayem

PS... I have never had a problem with the sensor on the radiator hose, never seen one fail.

janserce79

Thanks alot! This is the answer I was looking for. And yeah, I'm familiar with those "tricky" clips and O-rings. Tommorrow I'll tackle it and will come back with the results. Thanks alot for your help emjayem! I love this forum!!!!

janserce79

Aaaa one more thing I forgot! Do you know how much coolant will I loose after removing G62? I don't think it will be alot cause the sensor is pretty high...And yes I know to do it on the cold engine! :-)