2008 E92 M3 "Electrical System Malfunction"

[yardbro]

I know there are a lot of these posts on here which I have tried to follow as much as possible, but I figured I would throw up my own thread. I have an 08 E92 M3 that just hit 100k miles. Car has been relatively rock-solid and not given me any real issues in the past year of ownership however I have some electrical gremlins I am trying my best to track down.

When driving the car for a prolonged period of time, I will all of the sudden get the "Electrical System Malfunction" and the dash will go absolutely crazy for about 10 seconds. This is incredibly perplexing as this issue only shows up when using the car for just about an hour, then disappears again. I have never had this issue show up anywhere else i.e under heavy load, turns, idle, etc as long as its a drive that doesn't last over an hour.

My first suspicious was that the battery was weak, so i ordered a battery from the BMW dealership, replaced it, then coded and registered. The issue still remains. The next thing I did was go ahead and disconnect and code out my RDC module (TPMS was malfunctioning anyway). The issue still remains. I did some further looking around and found that both my headlight assembles had incredibly cracked insulation on all the internal wiring that I figured could not have been good electrically. I replaced both assemblies about a week ago. No success.

I have attached the codes from INPA that are stored after the malfunction happens, it's the same ones every time and almost all the modules pertain to having lost some sort of CAN communication. If I pull codes after driving and the malfunction hasn't happened there are none stored.

Any help or direction in what I should be checking next would be super awesome as I would really like to solve this mystery and don't feel like I could faithfully sell this car knowing that this happens.

JBBF:
A6CF
C907
C908

MRS:
C944
C947
940D

DME/DDE:
CDA8
CDB6
CDAA

EGS:
CF11
CF1A
CF26
CF22

PGS:
D2C4
D2C7

DSC:
D358
D35A

CAS:
D904

FZD:
DE84
DE85
DE87

GWS:
E099
E097

KOMBI:
A3B6
A3BC
A3B1
A3B3
E107
E104

MOSTGW:
E187
E184

PDC:
E207
E204

ZBE:
E2C4
E2C7

FAS:
E444
E447

BFS:
E484
E487

FRM:
E587
9CCD

CID:
E5C4
E5C7

[Adrian g.]

Given the year and mileage, I would check all the grounding straps.

[spammysammich]

Have all the recalls been done?

[yardbro]

The grounding straps are definitely something I will inspect the next time it is on the lift. Is there anything I should be looking for other than them clearly looking like crap?

Originally Posted by spammysammich

Have all the recalls been done?

I have documentation from a BMW dealership in 2020 stating that the positive batter cable recall was performed. Are there any others that pertain to the electrical system?

[spammysammich]

Yes. There are a total of 3 recalls. Two of which are electrical system fire hazards.

[spammysammich]

Also the FRM is notorious for bricking or having intermittent problems. Research that. A master tech buddy of mine had one take a shit as he was buttoning up the car to give back to the customer. There is an extended warranty on the frm.

[yardbro]

Originally Posted by spammysammich

Also the FRM is notorious for bricking or having intermittent problems. Research that. A master tech buddy of mine had one take a shit as he was buttoning up the car to give back to the customer. There is an extended warranty on the frm.

This is definitely interesting. I have looked a bit into this thinking that the FRM would be a suspicious part for this issue. I will do a bit of digging and possibly inspect/reseat the module and see where it takes me. It’s a huge pain trying to replicate the issue since it takes an hour to get it to act up. Thanks.

[spammysammich]

Good luck, anything CAN bus related is tough for me to understand and troubleshoot.

[BPMSport]

Originally Posted by spammysammich

Also the FRM is notorious for bricking or having intermittent problems. Research that. A master tech buddy of mine had one take a shit as he was buttoning up the car to give back to the customer. There is an extended warranty on the frm.

Not on the FRM2 which his car will have. This is a known issue on the later 10-13 cars with FRM3.

This sounds like an issue with the junction box to me. We have them in stock and can diagnose remotely. CAN usually won't cause this error to appear on the dash. OP If you include the fault descriptions it would likely be more helpful.

[yardbro]

Update on this:

I went ahead and took a look at the TPMS antenna which is located behind the underbelly paneling near where the driver's feet would be on the 08' E92. Everything looked fairly normal with the antenna, but I decided to go ahead and replace this part with an OEM replacement.

So far the electrical malfunction has yet to resurface after about a month. Seems strange, but the symptoms were definitely in line with what a lot of users had posted stating that the antenna was bringing down the CAN bus. Interestingly enough my TPMS system was malfunctioning since I bought the car, but I had coded that out pretty quickly since I don't really require it for my use-case. Makes sense as I guess this antenna is still connected to the CAN network even with the module disconnected and coded out.