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+---- Thread: Solved ✔ BMW F82 M4 "AC Compressor Clutch Short to Ground" [Solved] (/showthread.php?tid=81679)
BMW F82 M4 "AC Compressor Clutch Short to Ground" [Solved] - moreply - 30-07-2023
Hey Guys,
got a problem with my personal car. Due to some Sound from the drive belt, i changed the Clutch Coil, Pulley and Clutch Plate. Everything worked fine for two Weeks then my AC keept Shutting off.
Fault Code: "AC Compressor Clutch Short Circuit to ground"
So i did the whole testing procedure Resistance and so on. Ista cant detect any error after the procedure.
I already could figure out it only fails in higher RPMs wheres more force needed to Pull the Clutch on the pulley. In idle everything is fine. I suspect that the new Clutch does pull more current then the old one. I looked for currenct limits in FEM but cant find any.
I already disassembled the whole Clutch again to check for broken wires > nothing. It must be an Software issue.
Maybe someone knows the right Coding Strings. Thanks!
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" - liviu2004 - 30-07-2023
If the current exceeds the design max limit, how can be a software issue but rather a physical one?
You need to measure cold resistance from your coil and compare with genuine using the same tool and same ambient temperature.
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" - moreply - 30-07-2023
Problem is every value is the same. I exchanged the Clutch two times. My m2 Competition has the same Clutch no issues every value is the same. I meassured 4,5 Ohm at the two exchanged clutches and also at the M2. At 31 Degress Outside Temp.
The Clutch was working without issue before i changed the pulley. I also works for certain time in idle. It always stops at about 45min Runtime. Tought it might be an Temp issue, but with FAN directly on the Clutch same issue in idle.
I did run an Wire from Pin 4 on A173*2B directly from FEM to the Clutch and also used a different Ground same issue. Either Compressor is bad but then the Thermal Fuse would blow, or it just needs a bit more power that triggers the FEM Error
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" - weinerbarn - 30-07-2023
Did the old coil test bad or did you just replace due to the error and noise? Are you certain it's not compressor related? Has the system ever been opened or serviced?
"I already could figure out it only fails in higher RPMs wheres more force needed to Pull the Clutch on the pulley"
Compressor health, refrigerant charge, oil etc could also contribute to this.
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" - moreply - 30-07-2023
No Error and Noise were a different issue. Yes compressor cant be the issue it worked perfectly fine, before i changed the coild and so on.
Checked Charged and Oil. Whole systems was Vacumized and then refiled.
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" - bmchicago - 30-07-2023
sounds like you already made up your mind that it cannot be the compressor. If it were me i'd swap the compressor out with a known good one and retest versus any other probability.
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" - Beard - 30-07-2023
No Error and Noise were a different issue. Yes compressor cant be the issue it worked perfectly fine, before i changed the coild and so on.
Checked Charged and Oil. Whole systems was Vacumized and then refiled.
****************************************************************
Hello.
Pay attention to the gap between the clutch pulley and the magnetizing plate of the compressor shaft. Reduce the gap between them by selecting a spacer between the clutch pulley and magnetizing plate.
The washers have different thicknesses when assembling the air conditioning compressor, and are selected individually when assembling the compressor.
I've had this happen a few times when overhauling the A/C clutch.
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" - that4chanhacker - 31-07-2023
replace the whole unit, these AC compressors use a vicous coupler and operate on PWM so its not like on or off with 12v but im sure 100% PWM with 12v would turn it on but I digress. issues seems to be the unit its self. Make sure to replace the drier and expansion valve and condensor if you find any FM in there.
RE: BMW F82 M4 "AC Compressor Clutch Short to Ground" [Solved] - moreply - 03-09-2023
To let everybody know that the Acutal issue was. I didnt change the AC Compressor.
FEM Somehow had an Software Error. Updated the I Level no more issues
Thanks to everyone who tried to help!