Hi Guys, i'm new to posting. so be gentle.

i have a 06 530I blowing warm air and it just hit 100+ degrees in the car today in Florida. i grew up in Ireland so if i don't fix it soon im going to rent it out as a mobile sauna.
I have a bit of a time crunch thats why i'm bringing in the big guns.

I have previously read all the A/C threads I could find, and 2 trees from the amazon to print them out. But I need an A/C Wizard to help with Diagnostic.

I'm not sure how to check the sensors and the compressor or in what order.

Here is some Specifics

Trouble code: 9c54 IHKA: AUC Sensor
(I will post more codes later but i have to switch to windows to read them from scanner)

System has pressure, high low & high side pressure
the aux fan behind the radiator does not run when the AC is on
Max AC comes on and blows warm air randomly when it feels like it.
It does not get cold even at high speed.
When I press the snowflake button to turn on/off the AC unit, engine RPMs change

All inside settings set for cold
high amp fuse to the compressor & the low amp fuse from the dash are good.

i have Bentley Manual, and probably every document posted on the internet, I'm dizzy reading.
I have INPA, Rheingold and the Schwaben Professional Scan Tool For BMWs.
I have A/C gauges, A big drum of Freon, and all the tools required to turn it into a tank, a-team style.
I even have a 2008 528i to interchange parts if they are compatible.

But what i don't have is a solid answer to what components to start with or the proper procedure to check the a/c compressor.

I've read the HVAC Control Module sends a signal to the AC Clutch when told to do so & the pressure switch is connected in series, this means too low or too high pressure of R134a will not allow the compressor to engage. But i'm not sure how to check the sensors,


I did the rocker cover gasket, but i think it was leaking oil onto the compressor.
it was sitting a while and had a bunch of leaves in and around the filters at the bulk head under the hood.
it also had the water pump replaced, before I got it.
I reconditioned the Valvebody, mechatronics etc so its been up and down like a $5 hookers knickers on New Years Eve.

I would be eternally grateful if someone could help me get a little cold air blowing on this pasty white Irishmans head in the not too distant future, I seen a pitbull licking his lips outside publix today and i'm fairly sure he was thinking just another 5 mins and this ****er will be cooked just how i like em. Thanks in advance.

 

LOL, this is the best thread I have read on this forum in quite a long time.

Based on what I've read I'd bet you have a failed AC compressor. I'd start there. I need one too, mine is lazy and FL summer is fast approaching. Are you getting any high side or low side pressures with your gauges hooked up? Do you know if the compressor from your parts car is good?

 

Hey Kyle, I was actually looking for you on the forum, I remembered a guy from Tampa with a lot of knowledge on 530i. I believe I read some of your posts while doing the transmission.

I'm hooking up the gauges as we speak if I remember correctly I had high-pressure on the high side and high on the low side which I believe does point towards compressor.

Is it possible to test the compress with a multimeter, inpa, scan tool or a big hammer? I don't mind changing a compressor but if I changed it and found out it was a sensor or something silly, I'm like 98% sure I'd have to remove the rocker cover panel and beat it so hard it would be a 3 series by days end!!

 

Pressures Before starting

High side 110
low side 96




After starting the car and turning on air con pressure setting are

High side 110
low side 107




Turned off the car and let it sit for 5 mins.

pressure is climbing
High Side 115
Low Side 109






Aux Fan never engaged.

 

I think your compressor is shot.

Before you replace anything though, try running the car with the AC engaged, and use INPA to turn the cooling fan on. INPA has a test program that will let you turn the fan on.

 

Car running AC Button on and using the BMW scan tool to activate the aux fan. The fan activated and runs but no change to the AC operation.

 

[QUOTE=KyleB;1594029]I think your compressor is shot.

Is there any way to check the compressor before replacing it, like with a multimeter?

I read about sensors that stop the compressor from engaging if things are out of wack.

 

Just process of elimination, which you've already done.

The dead giveaway to me though is that you have high side and low side pressures that are pretty much identical. I'm 99.9999% sure your compressor is shot. I'll leave that .0001 margin of error on the table so you can't get mad at me if I'm wrong.

The compressor on these cars is a known weak point and it's not uncommon for them to fail at 10 years or less. They're a variable vane type and they do wear out.

 

"So your saying theirs a chance"

I found a 04 donor 530i from what I can tell compressor is the same. I'm heading in the morning to get the AC compressor, while I'm there what other parts would be a good idea to get. I want to tear it apart once and make sure it can be fixed in a few days, so I'm not .
I'd prefer to bring home a bag of parts and have them spare then be

 

you shouldn't need anything else, maybe grab a set of AC O-rings from your local Autozone just in case. It's never a bad idea to replace the receiver/drier whenever you open up an AC system, and thats something youd never replace with a used part. however, as long as you tape up the open line ends as soon as you disconnect them you should be fine.

double check to make sure that compressor is compatible, that '04 is going to be M54 powered, your '06 has N52.

good luck.