# Engine temperature gauge, Audi epic fail :(



## i_baked_cookies (Aug 28, 2007)

Okay, so over the past month I've had to take my car to the dealer 3 times for the same issue: a non-working engine temperature gauge, and the corresponding check engine light. The first time I brought it in, they replaced only one of the sensors. The gauge worked for a day afterwards, then failed. The second time, they replaced both sensors. Same business - gauge worked for a day, then failed. Third time they tested both sensors (I'm assuming by taking them off and trying them on another vehicle), and they are both working fine. They cleared the codes, and again, the gauge worked for a day, then failed.
What's interesting is that the gauge fails at nearly the same time after I get it back from the dealer... usually around 50 or 60 miles. Whatever they do (just clearing the engine codes) gets it to work for just a bit... so what on earth is making it fail?


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## tp. (Nov 12, 2009)

lemon law that sucker


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## dmorrow (Jun 9, 2000)

*Re: (tp.)*


_Quote, originally posted by *tp.* »_lemon law that sucker

Good luck with that on a four year old car.








You may want to try to find this issue in the 2.0T forum. Someone there had the same issue and in the end I think they believe they have a short in a harness somewhere. I don't remember the details but it was the same issue and the same pattern of events to try to fix it.


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## SilverSquirrel (Jul 24, 2006)

*Re: (dmorrow)*

what are the codes being thrown? If the the dealer wont tell you, take it to someone with a vag com and post up here.. 12 bucks says its 18613/P2181/008577 "Performance malfunction in Cooling System"
http://wiki.ross-tech.com/inde...08577


_Modified by SilverSquirrel at 7:47 AM 1-18-2010_


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## i_baked_cookies (Aug 28, 2007)

*Re: (dmorrow)*


_Quote, originally posted by *dmorrow* »_
Good luck with that on a four year old car.








You may want to try to find this issue in the 2.0T forum. Someone there had the same issue and in the end I think they believe they have a short in a harness somewhere. I don't remember the details but it was the same issue and the same pattern of events to try to fix it.

If it was a short in the wiring harness, or some kind of electrical problem, wouldn't the gauge cease to work no matter what they did? I find it weird that every time I bring it in, the gauge works for a day... and then fails. At any rate, I'm going to bring it back in and they're going to have to do something more than check the sensors and wipe the codes and just hope for the best... although I don't want to pay out of my ass to do some crazy electrical work...


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## krazyboi (May 19, 2004)

*FV-QR*

I feel like you might've had the most issues w/ a 3.2


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## SilverSquirrel (Jul 24, 2006)

*Re: (i_baked_cookies)*

THE GAUGE IS INTENTIONALLY DISABLED BY THE ENGINE MANAGEMENT COMPUTER DUE TO A FAULT REGISTERED IN COMPUTER. WHEN YOU CLEAR THE CODE, THE GAUGE WORKS, UNTIL YOU GET ANOTHER FAULT, AND THEN IT IS DISABLED AGAIN AND APPEARS TO STOP WORKING. WHEN YOU CLEAR THE CODE AGAIN, THE GAUGE WORKS. ETC ETC. 
THIS WILL NOT STOP HAPPENING UNTIL THE COOLING SYSTEM PERFORMANCE MALFUNCTION PROBLEM IF FIXED, MOST LIKELY A THERMOSTAT, OR UNTIL IT GETS WARM OUTSIDE AGAIN.
THERE IS NO DIRECT WIRE BETWEEN THE COOLANT TEMP SENSOR AND THE COOLANT TEMP GAUGE. IT IS ALL DONE IN SOFTWARE BETWEEN THE COMPUTER AND THE INSTRUMENT CLUSTER VIA THE CAN BUS. THIS APPLIES ONLY TO THE 3.2 A3 WHICH USES A 2 PIN (SINGLE) ECT. NOT THE 2.0T WHICH USES A 4 PIN (DOUBLE) ECT, ONE FOR THE COMPUTER, AND ONE FOR THE GAUGE.
YES I AM USING ALL CAPS.










_Modified by SilverSquirrel at 11:24 AM 1/19/2010_


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## terje_77 (Dec 19, 2005)

*FV-QR*


_Quote, originally posted by *SilverSquirrel* »_THE GAUGE IS INTENTIONALLY DISABLED BY THE ENGINE MANAGEMENT COMPUTER DUE TO A FAULT REGISTERED IN COMPUTER. WHEN YOU CLEAR THE CODE, THE GAUGE WORKS, UNTIL YOU GET ANOTHER FAULT, AND THEN IT IS DISABLED AGAIN AND APPEARS TO STOP WORKING. WHEN YOU CLEAR THE CODE AGAIN, THE GAUGE WORKS. ETC ETC. 
THIS WILL NOT STOP HAPPENING UNTIL THE COOLING SYSTEM PERFORMANCE MALFUNCTION PROBLEM IF FIXED, MOST LIKELY A THERMOSTAT, OR UNTIL IT GETS WARM OUTSIDE AGAIN.
THERE IS NO DIRECT WIRE BETWEEN THE COOLANT TEMP SENSOR AND THE COOLANT TEMP GAUGE. IT IS ALL DONE IN SOFTWARE BETWEEN THE COMPUTER AND THE INSTRUMENT CLUSTER VIA THE CAN BUS. THIS APPLIES ONLY TO THE 3.2 A3 WHICH USES A 2 PIN (SINGLE) ECT. NOT THE 2.0T WHICH USES A 4 PIN (DOUBLE) ECT, ONE FOR THE COMPUTER, AND ONE FOR THE GAUGE.
YES I AM USING ALL CAPS.












Why are you yelling?


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## SilverSquirrel (Jul 24, 2006)

*Re: FV-QR (terje_77)*


_Quote, originally posted by *terje_77* »_

Why are you yelling?

because.
If you READ the original post, and then READ my LINK ABOVE and READ my last all caps post you will find:
A scenario describing a problem that obviously a dealer mechanic was unable to diagnose correctly, let alone repair, and an actual VERY LIKELY CAUSE AND SOLUTION to this problem.
I am yelling to be heard more better. 
OP: print out this thread, and the other one you started on the same topic to which i also have contributed, and present to your dealer mechanic/service writer for comment. 
I have spent $$ chasing this same set of symptoms, and only have not yet replaced my thermostat because of the crappy weather in my driveway and the flu and family commitments. I refuse to pay more 75/hr shop $$ to do what i can do myself. Already blew 3 hours chasing a non-existant wiring fault, and replaced 3 ect senders and brand new G12.... 

THAT IS WHY I AM YELLING: TO SAVE OTHER 3.2 OWNERS THE WASTED $$ ON A PROBLEM THAT IS NOT COMMONLY KNOWN, AT LEAST HERE ON THIS FORUM




































thanks. sorry if my yelling hurt anyones sensitive ears.


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## MisterJJ (Jul 28, 2005)

*Re: FV-QR (terje_77)*


_Quote, originally posted by *terje_77* »_
Why are you yelling?


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## tp. (Nov 12, 2009)

why is that yelling? its just caps.


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## i_baked_cookies (Aug 28, 2007)

Jesus


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## tdotA3mike (Feb 5, 2009)

*FV-QR*

makes sense to me


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## azoceanblue (Aug 13, 2006)

*Re: (SilverSquirrel)*


_Quote, originally posted by *SilverSquirrel* »_THE GAUGE IS INTENTIONALLY DISABLED BY THE ENGINE MANAGEMENT COMPUTER DUE TO A FAULT REGISTERED IN COMPUTER. WHEN YOU CLEAR THE CODE, THE GAUGE WORKS, UNTIL YOU GET ANOTHER FAULT, AND THEN IT IS DISABLED AGAIN AND APPEARS TO STOP WORKING. WHEN YOU CLEAR THE CODE AGAIN, THE GAUGE WORKS. ETC ETC. 
THIS WILL NOT STOP HAPPENING UNTIL THE COOLING SYSTEM PERFORMANCE MALFUNCTION PROBLEM IF FIXED, MOST LIKELY A THERMOSTAT, OR UNTIL IT GETS WARM OUTSIDE AGAIN.
THERE IS NO DIRECT WIRE BETWEEN THE COOLANT TEMP SENSOR AND THE COOLANT TEMP GAUGE. IT IS ALL DONE IN SOFTWARE BETWEEN THE COMPUTER AND THE INSTRUMENT CLUSTER VIA THE CAN BUS. THIS APPLIES ONLY TO THE 3.2 A3 WHICH USES A 2 PIN (SINGLE) ECT. NOT THE 2.0T WHICH USES A 4 PIN (DOUBLE) ECT, ONE FOR THE COMPUTER, AND ONE FOR THE GAUGE.
YES I AM USING ALL CAPS.










http://****************.com/smile/emthup.gif


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## ProjectA3 (Aug 12, 2005)

*Re: Engine temperature gauge, Audi epic fail  (i_baked_cookies)*

i wouldnt really classify this as an "epic fail"
why dont you leave the car with them overnight. Let a technician or the shop foreman drive it home and back so they can see how/when the problem occurs.


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## tdotA3mike (Feb 5, 2009)

*FV-QR*


_Quote, originally posted by *ProjectA3* »_i wouldnt really classify this as an "epic fail"


x2 (when followers nuke themselves and take out HPFP/Cam/Follower) thats epic fail








/thread jack


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## SilverSquirrel (Jul 24, 2006)

*Re: FV-QR (tdotA3mike)*

Still want to know what fault codes on i baked cookies car. Go get a vag com scan or even a free pep boys or other scan, just to see what the fault code is.


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## i_baked_cookies (Aug 28, 2007)

*Re: Engine temperature gauge, Audi epic fail  (ProjectA3)*


_Quote, originally posted by *ProjectA3* »_
why dont you leave the car with them overnight. Let a technician or the shop foreman drive it home and back so they can see how/when the problem occurs.

First time they kept it for 1 night. Second time they kept it for 2. Third time they kept it for 3!


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## Rogerthat (Oct 23, 2005)

*Re: Engine temperature gauge, Audi epic fail  (i_baked_cookies)*

If you had an S40 this wouldn't happen. http://****************.com/smile/emthup.gif


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## 3G3T7I (Sep 30, 2005)

*Re: Engine temperature gauge, Audi epic fail  (i_baked_cookies)*

Don't bother letting the dealer drive your car, they probably still won't find and fix the problem. Save yourself some misery and just replace the thermostat. This is a common problem and should have been resolved by now.


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## tdotA3mike (Feb 5, 2009)

*FV-QR*


_Quote, originally posted by *Rogerthat* »_If you had an S40 this wouldn't happen. http://****************.com/smile/emthup.gif


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## SilverSquirrel (Jul 24, 2006)

*Re: FV-QR (tdotA3mike)*

S40 and other wisecracks belong in another thread.
If anyone has anything useful to contribute to this topic please post.
@I-baked-cookies: pm me with any updates, maybe i can help you get this sorted out. We seem to have the same issue.


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## portishead (Jul 28, 2005)

*Re: FV-QR (SilverSquirrel)*

I am having the same issue. My temperature gauge stopped working one day. It came back on the next day or so. Now it went off again, and it's been off for a couple days. Check Engine light didn't come on the first time, but it is on now, about the same time the gauge failed. I don't have a VAG COM cable to check the codes though. I need to take my car in for 55k maintenance. Any specific thing I can tell them about this problem? Should I just have them replace my thermostat?


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## Rogerthat (Oct 23, 2005)

Friday night domination!








SilverSquirrel, you need to be more serious.


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## SilverSquirrel (Jul 24, 2006)

*Re: FV-QR (portishead)*


_Quote, originally posted by *portishead* »_I am having the same issue. My temperature gauge stopped working one day. It came back on the next day or so. Now it went off again, and it's been off for a couple days. Check Engine light didn't come on the first time, but it is on now, about the same time the gauge failed. I don't have a VAG COM cable to check the codes though. I need to take my car in for 55k maintenance. Any specific thing I can tell them about this problem? Should I just have them replace my thermostat?

print out this thread and bring it to them. see what they say. 
If they give you a printout of the fault codes, post them up here. id be curious to see what they are. I would like to prove my hypothesis that the gauge dies on purpose when there are cooing system faults, on some cars.


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## Digipix (Jun 6, 2006)

*Re: FV-QR (SilverSquirrel)*

i just replaced my temp censer it took a **** on me around 79xxx mile i replaced it with a new one and it has worked right for about a week now, it will go just below the operating temp line (on cold days) anytime it is over 60 it works fine


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## portishead (Jul 28, 2005)

*Re: FV-QR (Digipix)*

FYI, my check engine light went off yesterday, and my gauge is working. I have an appointment Thurs, I'll see what I can find out.


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## portishead (Jul 28, 2005)

*Re: FV-QR (portishead)*

The dealer is keeping my A3 overnight. I don't know the exact code, but the tech said it was a cooling system malfunction. He said it could be related to the thermostat or some other sensor, I forget. I'll update tomorrow.


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## Digipix (Jun 6, 2006)

any up date????


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## portishead (Jul 28, 2005)

*Re: (Digipix)*

They wanted to replace my battery, but I'd rather do it myself. He just told me to tell him if I get the check engine light again after the battery change.


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## Digipix (Jun 6, 2006)

*Re: (portishead)*

i took mine to the shop and they replaced the thermostat all is good now http://****************.com/smile/emthup.gif


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## portishead (Jul 28, 2005)

*Re: (Digipix)*

Aw, my temperature gauge just turned off again! I think I may need to look for a DIY to replace the thermostat. I don't want the runaround with the stealership.


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## crew219 (Oct 18, 2000)

Audi epic fail = where they decided to locate the thermostat . . . 
underneath the intake manifold between the oil separator / cooler and the alternator....
So glad I purchased a replacement thermostat for my timing belt change.
Dave


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## Digipix (Jun 6, 2006)

*Re: (crew219)*

yea changing the thermostat is a pain in the ass like 3 hours


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## portishead (Jul 28, 2005)

*Re: (Digipix)*

My temperature gauge started working again today. This thing is crazy. I need to get that thermostat replaced.


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## SilverSquirrel (Jul 24, 2006)

*Re: (portishead)*


_Quote, originally posted by *portishead* »_My temperature gauge started working again today. This thing is crazy. I need to get that thermostat replaced.

I think after a certain number of "warm" runs the code clears itself and the gauge starts working again. We had a 3 day warm spell here, few days ago, and my cel went out and the gauge started working again. Then the cold canada air blew back in, and gauge went t*ts up.
Too cold here to do my thermostat in the driveway, so i went with plan B.
I bought a vag-com micro can, so now i just clear it out and the gauge comes back till the next fault








By the way, The bentley dvd has a 100 page white paper on the motronic software and all the engine management theory. I found a graph of what the computer expects for warmup temps vs. engine load, and it doesnt take much to make it "unhappy" and trigger a fault. Seems like a thermostat that is opening 10 deg C early is enough to be picked up.


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## portishead (Jul 28, 2005)

*Re: (SilverSquirrel)*

I finally got this taken care of at the dealer. You don't want to know how much I paid. I can post the info that has the parts listed that were replaced if anyones wants to know for future reference.


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## crew219 (Oct 18, 2000)

*Re: (portishead)*


_Quote, originally posted by *portishead* »_I finally got this taken care of at the dealer. You don't want to know how much I paid. I can post the info that has the parts listed that were replaced if anyones wants to know for future reference.

The thermostat is a pain to get to. I did it during my timing belt change and can't really see how mechanics can do it the way that the bentley suggests. Even with the intake manifold off, I had to remove the alternator to best get at the bolts holding it on.
Dave


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## SilverSquirrel (Jul 24, 2006)

*Re: (crew219)*


_Quote, originally posted by *crew219* »_The thermostat is a pain to get to. I did it during my timing belt change and can't really see how mechanics can do it the way that the bentley suggests. Even with the intake manifold off, I had to remove the alternator to best get at the bolts holding it on.
Dave

Just did my tstat today, finally.
Other than my back killing me, not as bad as it looks. The way you work on the VR6 is like any other audi, you need to undo about 50 things to get them out of the way to get to the part you want to replace. Airbox comes out, and you can get at what you need. You have to remove the entire thermostat housing, which means disconnecting all the hoses. 
I had on hand the new thermostat, and replaced all the orings as i went.
about 40 bucks plus new G12+, and a couple hours.
my new favorite tool is a remote cable operated hose clamp pliers for the spring clamps. I would have been swearing a lot more if i didnt have those. 
The audi engineer who spec'd the plastic allen head fastenters that hold the airbox to the bracket should be shot. 
Temp gauge shot right up to 90, even without clearing the code. Still had to use vag come to clear the cel and p2181 code.


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