2006 E60 A/C problem
 

My car (2006 E60) has one very strange problem with the A/C unit. The problem manifests like this: from time to time (random?) A/C does not work, and instead of cold air, it blows warm air. Outside temperature is very high (~38+C). But again, sometimes it works just fine and blows cold. And when it works, it works well. The only error stored on the computer is A468, but central display and LVDS work fine. Car is equipped with CCC and navi professional, I have the CCC screen. When querying the IHKA module, everything appears to be fine, except for the evaporator temperature, and it is pretty much the same as outside temperature, meaning probably that evaporator is not working. IHKA module reads high pressure on the ac unit, and that one starts rising as soon as AC is turned on, but unfortunately I forgot to write down the values :(

When I press the snowflake button to turn on/off the AC unit, engine RPMs change, so I guess the electronic clutch is engaging(?). When querying the IHKA I can see that the rpm of compressor changes with rpm of the engine, so I guess the compressor is working considering that the high pressure rises when AC is on. Also, IHKA states that refrigerant level is at 92%, so I guess that is OK. I have checked the refrigerant levels with A/C specialist, and he evacuated all gas from the system, and it had 810 g, which is normal. So we returned the same gas back to the unit. I have tried changing the settings on CCC screen, including the middle thing, and that did not help. I left it today with 3 bars on blue.

So the question is: any ideas how to diagnose this issue further? My indy mech told me to take the car to him when it is not working, but the first few times I took the car, A/C was working. Today though it did not work, but my indy was baffled with this problem, so I left the car there, and decided to try to ask on forums while he struggles in removing and testing parts.

Ideas?

I have had similar problems with cars in my life but not the E60
One friends E60 Aircon was not working properly and it was simply the micro filters blocked

The other obvious is the air con gas could be low
This sometimes triggers airconditioner compressors to switch on and off as the correct pressure is not in the line

The other problem can be the sensor that detects the temperature in the line could be faulty

I've had the same thing happen randomly on my '08 535xi. Annoying, and will likely remain so until a hard failure drives me to the shop. Nothing more aggravating than a problem that cannot be repeated.

Sounds exactly like low R134a refrigerant. I just went on vacation home and my father's and brother in law had the same problem.. just the cost of the adapters and refrigerant were so much more expensive than here in the USA! Ie what would have cost me less than $50 for two cars I easily spent $100 for the exact same things!

it is not refrigerant level :(
Checked, re-checked, evacuated all refrigerant, there was 810g there, added exact amount, same problem

Well, my indy suspects it is the compressor or some valve at the compressor, so he is dismantling it now. He will try to repair it (not sure if that is even possible). Will let you know if we figure this out. However, the reason I am not convinced it is the compressor is that the A/C works most of the time, but does not from time to time. At least indy is not expensive, so we can try this route without spending too much money.

Ouch good luck!

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well, it turns out, it is the compressor, and it cannot be fixed. Ordering a new one. I really hope that it will fix the problem. But I will be without the car for a week until new one arrives :( and aside from the A/C issue the car is a pleasure to drive, and now I have to abstain from driving for a week or so :(

how did he confirm the compressor is dead?