External temperature sensor

[MarkPRS6]

Hi Guys

Well another question on the lovely RS6.

Can you tell me where the external temperature sensor is on the RS6 avant please? I haven't had a look yet as I'm constantly out of the country so time is an issue. Mine reads funny, like 16.5degC when there is frost all over the car so I'm not 100% sure its right.

I'm trying to gauge how much of a job it will be to change it over so I can order the parts ready for the next time I see the old girl.

I'm hoping its not an engine out job as per every other job on the car.

Cheers

[SuprSi]

It's clipped into the oil/atf cooler duct on the right hand side (looking at the front of the car). You should be able to reach down the front of the car with the bonnet open or through the bottom grille if you pull that off. Usually it falls out and reads high so sounds like what's happened with yours

[Shoppinit]

Even when it's working its readings are still more or less pure fantasy.

[ChrisRS6]

I found it to be relatively accurate if you are moving at a decent speed so you get fresh air flowing over the sensor. Once you hit traffic, it just seems to pick up heat from the engine bay.

Apart from giving a jibberish reading, I didn't notice this ever caused any problems in my old RS 6.
Is the exterior temp linked to anything important like interior climate control or any engine air-flow things?

[bam_bam]

No point to it, ignore it.

[R5XVB]

Mine's utterly F'd too, normal reading -46.5C etc then once in a blue moon it works, swapped for a genuine part, checked most of the wires and came to the same conclusion as Bam. It's pointless anyway...

[MarkPRS6]

Anyone have a diagram or photo showing the location of the sensor. I've had a hunt all around the front of the car and I can't see anything that looks like it could be the ambient air sensor.

It was so obvious in my old 911

[Nobby]

Have a look at this guide. The sensor slots through the plastic duct around the bottom cooler. The photo of the front of the of the car you can see just a circular black dot on one side (its not on the other side) above the bucket of coolant. Its quite low down though, near the bottom.

download/file.php?id=21302

[ahoooga]

From the Bentley manual that's;
2 inches thick,
500 odd pages long,
considered to be the 2nd most important reference for repair ( after VCDS),
costs a fortune
Item Number 5 - Its THAT important, the picture is the only mention of it in Bentley
You'd get more accurate temp info by sticking your head out of the window to see how hot/cold it is.

[live.marc]

Very helpful post.

Not sure if anyone would still see this as this post is old, but will give it a go

Would this temperature sensor failing cause the aircon to not work properly? Also, would the cab air temp sensor failing also cause the aircon to play up?

[Nobby]

I guess if you put it in auto and it thinks the car is cold it might not turn the air con on. There are multiple sensors though and each outlet has its own temperature sensor I believe. There are quite a few flaps which can mess things up too.

You really need VCDS to tell you what the HVAC is seeing and trying to do.

[Bradders911]

I watched mine go from 19c to 15.5c and then to 21c in about 20 seconds today. Something else that's foobared. The list is getting bigger daily.

[Shoppinit]

They all do that. It's the crappest sensor in the world.

[Bradders911]

A balmy 28c in Leeds today

[simonpoulton]

Mine works spot on! I don't have the plastic air flow channel thingy that directs air to the oil cooler so the sensor is just flapping around. Not sure if that makes a difference with the heat of the engine?