[def1nity]

Hello!

I hope someone here can shed some light on what's happening with my IHKA and A/C compressor as I have been dealing with this problem for quite a while now and I'm almost ready to throw in the towel and start changing parts left and right, almost at random

Short summary:

- e90 pre-lci 2006 330d (converted to 335d in terms of order and positions in the engine compartment)

- The 335d conversion included compressor and A/C lines straight off a 335d

- Also replaced my IHKA module with the exact same one as the Driver Temperature knob was acting up on the original.

- Last year it mostly worked (the only annoyance was that there was no A/C in the first 10-15min of starting it up.

- This year however it looks to have developed a mind of its own which mostly decides to torture me because f*** me, that's why

It rarely turns on, if at all and soon after it turns off by itself dumping all of the moisture it extracted right back in the cabin...

Pressing the A/C button on the IHKA used to generate an error in the module - E72D (basically a message time-out condition)

What I've done so far:

1. Updated the IHKA and JBF modules with WinKfp to the latest available patch (My datens is v69 if memory serves me right)

2. Coded both modules with NCSExpert back to factory settings

3. Overwrote their UIFs + replaced their VIN field values with the original one from my car

4. Dissasembled the IHKA module completely and literally soaked it in contact cleaner. The connectors on the back of it were also contact cleaned. Additionally I unplugged the pressure sensor on the A/C high pressure side and thoroughly cleaned the connector, wires and the sensor itself (didn't take it out as system was under pressure). Left things to dry-up well and put all of it back together.


5. My last move was to go to an A/C shop where I asked for the system to be fully evacuated and then filled up with the required amount of oil and refrigerant as I read somewhere that most places only add refrigerant when you go for a "check and top-up", thus diluting the mix. Without oil the compressor's protection kicks in as there is risk of overheating.

The shop removed around 450g of refrigerant and mentioned there was barely any oil in it...

They added both required fluids according to BMW's spec to a total of 590g

After all of this, the results:

- There are no more errors getting logged by IHKA!

- The A/C works more often and for longer than before!

- Huge improvement, but I would like for it to work 100% of the time as before, rather than 50-75%...

- All the sensors (temp, humid, solar) report back correct data.

- The refrigerant pressure reaches between 15-18 bars from INPA/ISTA, WHEN it actually starts working.

- A/C still trying to give me a heat stroke as it just stops randomly while on the road and has no clear condition about when it will start again.

- I've noticed that turning off the snowflake button for a while and then trying it again after lets say at least 15min, has proven the superior tactic than just pressing the button on/off until it starts blowing cold...

The garages I've discussed this with would like to change the compressor directly but don't guarantee that the problem will get solved... Professional guesswork looks embarassing to me considering the simplicity of the A/C system in these cars.

Appreciate any pointers and troubleshooting tips, that can help me figure out this mystery before the heat gets me...


p.s. I only updated and coded the IHKA and JBBF modules as mentioned in the start. All the other modules are on their original SW level.