I'm not a VCDS expert and am reasonably certain that what you've said is correct for the A2 as it is one of the earlier systems that VCDS can work with - however there is an indication in one of the VCDS forum technical posts that some VAG systems at least can give a reading for both actual *and* an adjusted external temperature value - which makes me wonder if the same is possible if you know exactly which adaptation channel to modify to fine-tune the reading (in the same way that I can adjust the fuel tank needle position or other similar parameters in the dashboard).I'm, (almost), certain there's no provision for ambient temp sensor calibration.
Check the sensor you have is OEM.
Other than that, beg or borrow another sensor, and compare readings, with sensor in something to keep it at a constant temp, such as water. It must be water proof, given where it is located!
Mac.
Yes, just a resistor.I'm not a VCDS expert and am reasonably certain that what you've said is correct for the A2 as it is one of the earlier systems that VCDS can work with - however there is an indication in one of the VCDS forum technical posts that some VAG systems at least can give a reading for both actual *and* an adjusted external temperature value - which makes me wonder if the same is possible if you know exactly which adaptation channel to modify to fine-tune the reading (in the same way that I can adjust the fuel tank needle position or other similar parameters in the dashboard).
However - it is not made clear how one would go about effecting the adjustment.
see link - https://forums.ross-tech.com/index.php?threads/633/
....
2) Check the Measuring Value Blocks(MVBs) for the following (most MVBs will be labeled and you will be able to identify the data in the field):
For the problem in hand it may be that a different sensor (or just cleaning up the connectors on the existing sensor) may give a different reading as isn't it purely a resistance that is being translated into a temp value rather than having to tinker in the software?
- Compressor shut off code
- Refrigerant Pressure from the Sensor G65
- Outside Temperature (filtered and unfiltered) (adjusted vs. not adjusted)
- Evaporator Temperature
- Vent Temperatures
You could, to start with, compare the resistance of the two sensors with a multimeter.Yes, just a resistor.
Mac.
Ill have a butchers at weeekend! good tip, full of hope nowfor what its worth, @CrispyEdd my outside temp was measuring a good 10* over following a thermostat swap.
everything looked ok, no leaks etc so i took the grill off, gave the outside temp probe a little wiggle and its now ok!
could be slight corrosion on the connectors maybe? despite it being well wrapped it is rather exposed to the elements out there in front of the rad.
drew
I have one of these if required Edd, probably easier than messing around with ECU etc.Okay I'll try and for another one..I'll place a wanted
Ill have a butchers at weeekend! good tip, full of hope now
The Ambient Temperature Sensor, (to give it the official title), is connected to the Climatronic, so the conversion from resistance to something digital, probably happens in there. There are quite a few old posts with similar, 2 - 3C offsets, but no fixes that I could find. Sensor replacement, from older posts, doesn't seem to fix it either. So it looks like the "problem" is in the Climatronic, so maybe a clean up of the blue, 32 pin connector, (+, pin 29), and the infamous headlight earth, is worth a try.Hi Drew, I was staring at it yesterday through the grill, I havent yet replaced it though Still annoys me even though its just +2 deg c.
Im not sure the coolant temp sensor will be doing anything with the ambient sensor, as far as I know they are totally separate. The coolant temp sender down side of a tdi is 4 wired, 2 for guage 2 for ecu i believe. THeres a coolant temp after the radiator also. Tis odd
So yours reds like +10 deg over ambient? Even after swapping it out? SO I would say thats either wiring corrosion or the reading comes from something else also...
One for the bigger A2 brains...
insightful as ever, mac. thank youThe Ambient Temperature Sensor, (to give it the official title), is connected to the Climatronic, so the conversion from resistance to something digital, probably happens in there. There are quite a few old posts with similar, 2 - 3C offsets, but no fixes that I could find. Sensor replacement, from older posts, doesn't seem to fix it either. So it looks like the "problem" is in the Climatronic, so maybe a clean up of the blue, 32 pin connector, (+, pin 29), and the infamous headlight earth, is worth a try.
Edit: The + connection from the sensor itself runs through a white T17 pin connector in the left A pillar, on it's way to the Climatronic, according to the schematic. I had a windscreen leak, and that area got pretty damp, so worth a check in there too.
Mac.
Yeah as far as I can see it's the only sensor, shame mine over reads somehow!Sensor & your other parts on their way Edd, its via the sensor that the webasto know when to switch on I believe