[F90Finn]

Parked up after a spirited drive to grab a drink, came back out and started the car to go home and I got a drivetrain malfunction message and a CEL. Car had a rough idle and just sounded horrible and a bit of vibration when I drove even at low speeds. Got come and called the dealership to set up an appointment. I go back out to start the car to take it to the dealer and the rough idle is gone, car seems 95% normal, the other 5% might just be me mentally scaring myself lol. But the CEL is still showing without the drivetrain icon and message. Does this sound familiar to anyone? 2021 m5c 33k miles

Update: it ended up being the expansion tank leaking into the injectors etc, so luckily they’ll be covered by warranty now

[AHall]

Originally Posted by F90Finn

Parked up after a spirited drive to grab a drink, came back out and started the car to go home and I got a drivetrain malfunction message and a CEL. Car had a rough idle and just sounded horrible and a bit of vibration when I drove even at low speeds. Got come and called the dealership to set up an appointment. I go back out to start the car to take it to the dealer and the rough idle is gone, car seems 95% normal, the other 5% might just be me mentally scaring myself lol. But the CEL is still showing without the drivetrain icon and message. Does this sound familiar to anyone? 2021 m5c 33k miles

Have looked under the hood around the antifreeze tank for leaks?

[M5_508]

Originally Posted by F90Finn

Parked up after a spirited drive to grab a drink, came back out and started the car to go home and I got a drivetrain malfunction message and a CEL. Car had a rough idle and just sounded horrible and a bit of vibration when I drove even at low speeds. Got come and called the dealership to set up an appointment. I go back out to start the car to take it to the dealer and the rough idle is gone, car seems 95% normal, the other 5% might just be me mentally scaring myself lol. But the CEL is still showing without the drivetrain icon and message. Does this sound familiar to anyone? 2021 m5c 33k miles

Possible coolant tank issue. Maybe coolant leaking into the fuel injecters or cylinders ?

[F90Finn]

Originally Posted by M5_508

Possible coolant tank issue. Maybe coolant leaking into the fuel injecters or cylinders ?

That’s what I suggested to the dealer, I’m hoping that is the case because then they should cover the injectors through warranty I’d assume

[F90Finn]

Originally Posted by AHall

Have looked under the hood around the antifreeze tank for leaks?

Yeah I didn’t notice anything but maybe the dealer will find something, let’s hope they don’t lie about it. I have no trust in dealers.. had no issues with this car then I go to the dealer for an oil and brake fluid change a week ago now this happens 🤔

[M5KEITH]

Drive train malfunction and running rough is because you need new injectors. While they are in there replace all 8 coils.

I had this happen to my wifes X5 with 4.4 M5 motor at 37,000 miles and it just happened to my 2018 M5 at 40,000 miles.

I’m am replacing plugs and coils at an Indy Shop for $1300 includes parts and labor.

Dealership will want north of $1800 to do it or higher.

[F90Finn]

Originally Posted by M5KEITH

Drive train malfunction and running rough is because you need new injectors. While they are in there replace all 8 coils.

I had this happen to my wifes X5 with 4.4 M5 motor at 37,000 miles and it just happened to my 2018 M5 at 40,000 miles.

I’m am replacing plugs and coils at an Indy Shop for $1300 includes parts and labor.

Dealership will want north of $1800 to do it or higher.

That’s what I’m expecting the issue to be. However, would the fact that it went back to driving like normal and the drivetrain malfunction message going away possibly mean something else is the issue?

[jnotrom711]

had this happen 2x. Both times was vanos sensor needing to be replaced. At about 35K miles then 40K miles on the other one.

[F90Finn]

Originally Posted by jnotrom711

had this happen 2x. Both times was vanos sensor needing to be replaced. At about 35K miles then 40K miles on the other one.

Interesting, I feel like a sensor being the issue would make more sense considering my symptoms went away before taking the car in. Hopefully it is this

[M5KEITH]

Originally Posted by F90Finn

That’s what I’m expecting the issue to be. However, would the fact that it went back to driving like normal and the drivetrain malfunction message going away possibly mean something else is the issue?

Possibly you could run a scanner tool for code(s)

[jnotrom711]

Originally Posted by F90Finn

Interesting, I feel like a sensor being the issue would make more sense considering my symptoms went away before taking the car in. Hopefully it is this

when it happened to me, similar situation. CEL, limp mode, redline (maybe yellow?) went to like 4000 RPM I think on the guage, and drove very rough. I was able to drive it home or to a dealer, and same thing it would go away after restarting the car, but would come back, and eventually I believe it stayed on.

It wasn't a major repair on mine, and was under warranty.

The irritating thing was there is 2 of these (I think) and one went out, then the other a couple months later, so that was irritating they didnt just change them both.

So I would try to get them to do both if possible (if this is your issue) so you dont have to bring it in a little bit later for the other.

I dont believe its a very costly repair or part if its not warranty.

but I could be the coolant tank also, and leaked down on the fuel injectors.

[jnotrom711]

Originally Posted by F90Finn

Interesting, I feel like a sensor being the issue would make more sense considering my symptoms went away before taking the car in. Hopefully it is this

when it happened to me, similar situation. CEL, limp mode, redline (maybe yellow?) went to like 4000 RPM I think on the guage, and drove very rough. I was able to drive it home or to a dealer, and same thing it would go away after restarting the car, but would come back, and eventually I believe it stayed on.

It wasn't a major repair on mine, and was under warranty.

The irritating thing was there is 2 of these (I think) and one went out, then the other a couple months later, so that was irritating they didnt just change them both.

So I would try to get them to do both if possible (if this is your issue) so you dont have to bring it in a little bit later for the other.

I dont believe its a very costly repair or part if its not warranty.

but I could be the coolant tank also, and leaked down on the fuel injectors.