Hi.

My IHKA gives alarm 9C 54 64, I bought a new sensor and still I get the error, I then checked wiring and all 3 wires going to sensor is ok.
Also noticed problem with solar sensor(0x3d3) E720
IHKA is from E65 I believe had to upgrade to lci due to NBT retrofit.
Could there be something missing in programming?
BMW 520i E60 2004

 

There could be something wrong with the programming but the AUC is the same no matter what system you have.

To me the AUC is not worth changing out it adds no benefit and you could go down the rabbit hole trying to fix it. What was the part number you used

 

Hi,
I also have the same problem, I tried a couple of used working sensors and no luck, decided to buy a new 1 but still no luck..
Anyone had the same problem?

 

You assumed that code 9C54 is always a broken AUC sensor.

Time to run an exercise.

Clear the fault codes.

Turn off the circulation button on the climate control panel. Leave it off.

Wait a while to see if the code reappears.

 

Well the benefit would be that it automatically changes between outside and inside air.
Part number 64116933052

I tried turning off circulation then clearing the error but it came straight back

 

The sensor is exposed to the outside elements (e.g. water, etc).

When you unplugged the sensor did you look at the 4 pins?

Are they all there? Are any corroded?

Spray CRC electrical cleaner on the harness connector?

 

Wiring is ok, i checked them all the way to the climate pannel using a multimeter

 

Looking over wire diagram for E60 after 2007(facelift) I see that AUC+ gets power from fuse box and not pin 2 on IHKA. Gonna check if there is 12v on pin2 if not I will try to reroute

 

Took out pin2 from ihka and gave it 12v+ and problem is gone

 

Was pin 2 bent?

Was pin 2 corroded?

What was going on with pin 2?