[MarcoZandrini]

2018 M240i with the 6 speed. Parked the car, put it in first, and shut the engine off. Heard a lot bang from the rear. Thought, "Crap, I lost a spring." Checked the car out, pushing down on each fender. With a flashlight I crawled under the car. All looked good, the springs and shocks looked fine. No leaks. Checked the serpentine belt; it was fine. Scanned the car with bimmerlink. Bunch of electrical codes, and found 2 codes: 213A2D ("dual mass flywheel, protection; harmful operating point detected") and CDA505 (ignore as the car doesn't have EGS). See the attached pic. I tried to clear all of the codes but these two codes would not clear! I took the car for a short spin. It shifted fine, no noise, no jerking, nada.

I contacted a friend of mine who is a BMW master mechanic. He's in NC and noted that the clutch may need to be replaced. The car has ~36k miles on the odo. Tracked 3x. Original battery.

Did some research on the net, and some pointed to the battery. I don't think it's the battery.

Any ideas?

Thanks!

[TrboMike]

Ok I'm not familiar with the code or the sensor behind it. But a dual mass flywheel that was bent or had spring damage would make a lot of noise. Especially at idle or during starting.

Two things you said:

"had a bunch of electrical codes and found two codes" Was there other codes besides these two? A "bunch" of codes at once can be a electrical problem like low voltage or spike, or bad ground caused a pulse of codes at once.

"put in 1st, shut off car. heard loud bang" that sounds like the motor was still turning and you dropped the clutch right as it was shutting down. Did the car lurch? A jolt thru the trans/flywheel/clutch/driveshaft/axles and all the sensors involved right as the ECU is shutting down could flag some codes. I would expect them to go away tho with a clear. Did you try a battery disconnect reset?

[MarcoZandrini]

Originally Posted by TrboMike

Ok I'm not familiar with the code or the sensor behind it. But a dual mass flywheel that was bent or had spring damage would make a lot of noise. Especially at idle or during starting.

Two things you said:

"had a bunch of electrical codes and found two codes" Was there other codes besides these two? A "bunch" of codes at once can be a electrical problem like low voltage or spike, or bad ground caused a pulse of codes at once.

"put in 1st, shut off car. heard loud bang" that sounds like the motor was still turning and you dropped the clutch right as it was shutting down. Did the car lurch? A jolt thru the trans/flywheel/clutch/driveshaft/axles and all the sensors involved right as the ECU is shutting down could flag some codes. I would expect them to go away tho with a clear. Did you try a battery disconnect reset?

I put the transmission in first and then shut the engine off. That's when I heard the bang. It's my SOP.

[MarcoZandrini]

Update: the code (213A2D) cleared. Again, the car drives normally.

[MarcoZandrini]

So far everything still works perfectly. I'm starting to believe that the loud noise was the clutch throw out bearing releasing from the clutch pressure plate. I'll keep you up to date.

Btw, my indie (J&F Motors in Shirlington) sez a new clutch+flywheel will cost me $4k!!

[MarcoZandrini]

Still driving fine.