[everywill]

Just learnt a 600+ pound lesson. If you are a DIYer fiddling with coding, please read; and hope you won't make a mistake as I did.

My car is an Oct 2012 built F30 320d with automatic transmission and climate control. At the beginning of this summer, I found my ac didn't work. Checked by using ISTA-D shows there's a "Valve status unknown“ fault code in the IHKA module. Then booked in to a reputable local BMW specialist who suggested the compressor need to be replaced.

Since the original BMW part costs over 1200 GBP including VAT, I thought its probably better to buy an used one off ebay, which I did. Here's whats disaster happened.

According to BMW ETK and realoem and all other parts resellers' website, there are 2 compressor variants of 2012 F30 320d, one with clutch and one without:

http://www.realoem.com/bmw/enUS/show...diagId=64_1882

Because mine has auto trans and climate control, it clearly should be the one without clutch. It turned out I'm wrong after mechanic disassembling everything on the way showing it did has a clutch. Then, in order to get this done ASAP, I just let them sourced a brand new OE part (430GBP).

However, they informed me this afternoon that the new compressor is still not working and there seems to be something wrong in coding. All of sudden, I realized something that could be the cause. I immediately went to the garage with my laptop and ENET cable and did some tests on my theory and icy cold air came out of vent......

Here's the thing. Last December, I upgraded the head unit to NBT system with DAB tuner by myself. Apart from coding on the HU-H module, I also coded FEM based on suggestions from others. The one thing vital here is the change of build date. As NBT was not available in 2012, I changed build date to 0713 and coded FEM along with other relevant control units.

One related question here is why every catalog says my car should have a compressor without clutch but the fact is opposite. My guess is Oct 2012 was on an edge of changing build spec (with clutch before that date and without after that date). By modifying the value in FEM, the control unit thought it suppose to seek for newer valve control instead of older clutch control; but it just not there. This will also explain why there's a fault code as "Valve status unknown“. Based on my limited knowledge, a traditional clutch based compressor shouldn't transmit valve message to computer. So, at the garage, I use Esys to recoded FEM and IHKA to original build date and; as stated, everything worked.

Since the very beginning, there's nothing wrong with hardware but one digit mistake during coding.....

Although there seems to be some faults of the mechanic who made the initial diagnosis, I still bite the bullet and paid the full bill considering the fact that they are likely never expect customers screw up coding. Anyway, an expensive lesson for me; and hope it can also benefit you guys.


BTW. contact me if anyone in the UK (preferable in Southampton area) needs a compressor for 2012 F30 320d, I have both types of it. Hope I can recoup some costs....haha

Have a good weekend!

[F30ed]

My God, what a story. Sounds that in this modern time we should treat digits same way as real metal parts. Relation between "soft"ware and hardware becomes so tight that changing a number can have same effect as wrenching some time ago. I am glad you did not break anything. And I glad compressor did not fail, or it would be probably the first case reported.

[akru88]

Sorry for my bad English , i have a problem with my car the ac compressor just stop working ac only blow hot air. Manual 2013 model year without Nav , my cic was dead in 2016 so bought an nbt evo unit with id4 from a 2015 car. Ac was working fine till now and no error message from the climate unit what my enginer told me . Compressor dont start when i press the ac , it can bad coding? Or just need to buy a New compressor? I know my nbt unit make some fail message from the bad coding .. but if it working for years can it be cause this kind of problem ?

[Ibo24]

Akru: search for AIC_Kompressor_clutch in FEM and put it on active.

[akru88]

Originally Posted by Ibo24

Akru: search for AIC_Kompressor_clutch in FEM and put it on active.

Big Thanks its save me a lot of money after coding ac working as it new

[Ibo24]

Originally Posted by akru88

Big Thanks its save me a lot of money after coding ac working as it new