Sensor for Evaporator Outlet Temperature (G263)

humps

humps

A2OC Donor
VAG-COM check showed this fault code:

00818 - Sensor for Evaporator Outlet Temperature (G263) *****
30-00 - Open or Short to Plus

This probably explains why my air-con wasn't always pumping out cold cold air in the summer. It only managed some cold-ish air. However, my climate control has always had A/C because I compared it under econ mode and the condenser was replaced in Mar05 as part of a repair, so it could be my sensor is half borken... What do people think? Is the part 6Q0 907 543 D ?

Also, earlier this year, one weired drive, I went through all weather in one day (Sunny, windy, big/small hail storm, fog, rain and big snow). It was when I hit a sudden down pour of thick snow, my car's interior misted up really badly and quickly, I had to slow right down because I couldn't see a thing at 50mph! I had to use the demister for the first time! No doubt the A/C was switched off suddenly, but was it to do with the outside temp change? I've had driven through freezing weather but the climate and always sucked out the moisture and my A2 never misted...
 
Hi humps
As we discussed at ADI, this is what happened to my car.
My interpretation is that the evapourator outlet temp senser continually monitors the cold, dry air entering the cabin and compares this with the output of the other cabin sensors and the temp dialled into the climate control. The air con compressor is then signalled to work harder if more cold air is required. If the G263 sensor fails then my guess is the climate control uses a default setting, allowing the system to continue working at reduced efficiency which cannot cope with very hot or humid condions.
The sensor p/n above is the one I changed on my car. It cost £15.03 + vat a year ago. The bad news is that replacement involves removal of the dashboard. I tried every way possible to avoid this even after removing the dash I could not see an easier way of doing the job.
The attached illustration shows the location of the sensor - this shows a LHD car so the positions are reversed for RHD
The only thing I did not investigate was the possibility of doing more checks on the sensor before removal - tracing the wires back to accessible pin-outs for example for checking with a meter

Cheers Spike
 
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thanks spike, I've done a bit of googling around and found various non english websites talking about the G263 sensor on different models upto the A8. It seems your idea of CC working at some default efficiency make sense. Since the part is so cheap, I'll order the part anyway. I think I have the whole christmas to play with it, while looking out for a double DIN dash ;-)
 
According VAG-COM I've same problem - broken evaporator outlet temperature sensor.
Do you have any photos or something to see / explain location of sensor?

spike said:
Hi humps
As we discussed at ADI, this is what happened to my car.
My interpretation is that the evapourator outlet temp senser continually monitors the cold, dry air entering the cabin and compares this with the output of the other cabin sensors and the temp dialled into the climate control. The air con compressor is then signalled to work harder if more cold air is required. If the G263 sensor fails then my guess is the climate control uses a default setting, allowing the system to continue working at reduced efficiency which cannot cope with very hot or humid condions.
The sensor p/n above is the one I changed on my car. It cost £15.03 + vat a year ago. The bad news is that replacement involves removal of the dashboard. I tried every way possible to avoid this even after removing the dash I could not see an easier way of doing the job.
The attached illustration shows the location of the sensor - this shows a LHD car so the positions are reversed for RHD
The only thing I did not investigate was the possibility of doing more checks on the sensor before removal - tracing the wires back to accessible pin-outs for example for checking with a meter

Cheers Spike
Click to expand...
 
Yes I have, but not sure if you really want to know! In short, if the sensor is really at fault, you need to remove the entire dashboard and get behind the central bulk head, reach down with a small hand to get it out.

As it turned out, my problem is not the sensor, i took it out and measured the resistence according to ElsaWin and against a replacement sensor. In the end, the condenser died and the fault code was wrongly reported by the CCU. I didn't need to replace it at all!
 
Thanks Humps for fast reply.. I'm newbie in this forum and yes I've quite small hands but maybe too short nerves to start playing with dashboard removal :) Anyway I just bought my A2 a week ago and I really do not want to "brake it" :)

When I'm saying that sensor is broken, that is based only what VAG-COM informs.. This same error msg game also with autodata diagnostics. I haven't got possibility to test A/C because climate in Finland is already rather cold, -5 degrees.
Maybe it is better for me to wait for summer and warmer conditions to see if A/C is working or not or do you have any ideas how to investigate if sensor is really broken. F.ex where begins the wiring for sensor. I mean to measure resistance from that point if it is more easily reachable?
Just in case I would like to have link or something where I can see how dashboard is mounted and how it can be demounted. I would also apprechiate info about sensor location. Thanks..
 
Your thinking is exactly what I thought. Unless you get a lot of mist inside the car, leave the a/c out until the summer where it is much easier to check. When the sensor is reported broken, the CCU will only operate the a/c at reduced capacity not completely off. So when the temp is warmer, you can tell the difference between a/c completely dead or working at reduced capacity via the temperature at the air vent.

If I suspect you have a dead condensor, then there will be no difference, which means replace the condenser and clear the fault code, don't need to take the dashboard out! I may have a single diagram of the a/c unit on paper, the dash removal is all from ElsaWin which I suggest you source it via some means (which I'm not going to promopt any illegal downloads ;-) )
 
Hi mclaine
You may be able to test the G263 sensor by checking the termination points of the 2 wires from the sensor. It means removing the climate panel and disconnecting the multi pin plugs but its a lot easier than pulling the dash out. (Which I did on my car and luckily it was the sensor which had failed)

grey / red wire from G263 sensor runs to terminal B15 on the climate control panel.
green wire (earth) from sensor links into terminal B5 on the CC panel.

Cheers Spike
 
spike said:
Hi mclaine
You may be able to test the G263 sensor by checking the termination points of the 2 wires from the sensor. It means removing the climate panel and disconnecting the multi pin plugs but its a lot easier than pulling the dash out. (Which I did on my car and luckily it was the sensor which had failed)

grey / red wire from G263 sensor runs to terminal B15 on the climate control panel.
green wire (earth) from sensor links into terminal B5 on the CC panel.

Cheers Spike
Click to expand...

Thanks!

That's what I'll do! I tried to find ElsaWin to "maybe" dowload some instructions for removal of parts in dashboard - now in this case A/C -panel.
Any links to find Elsawin or any exploded view of dasboard..

Any layout of these different terminals in climate control panel?
 
mclaine said:
Thanks!
Any links to find Elsawin or any exploded view of dasboard..

Any layout of these different terminals in climate control panel?
Click to expand...

The terminal positions in the connector blocks are numbered so you should easily be able to identify the specific wires from this and the wire colours provided. You really need a manual before starting bigger jobs so check out this link or look on e.bay
http://www.a2oc.net/forum/showthread.php?t=8554

Cheers Spike
 
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