F11 520D, Banging noises from drivetrain, screen warning... Solved it in 20mins!

[Pallox]

Greetings,

I've got an advice here regarding a horrific problem i struggled with...

Had such an awful issue with my F11 520D 2011 that i fixed myself, after paying aprox. 2000dollars to a workshop for fixing nothing...

So, driving along and suddenly a repetetive banging noice from the drive train, as if a tiny gremlin sat in there with a small hammer, wanting me to let go of the accelerator. The hammering did not change pace with the rpm, he held a constant rhytm there and stopped when pressing the clutch.. After a couple of minutes, warnings started pinging up on the screen! -Head for a BMW handyman as soon as possible!

Eventually i did, they said it was the clutch and flywheel that had broken and needed to be changed. Expensive stuff.. no issues at all with the clutch though, all felt like new but ok. Lets get it fixed. Although, it remained. Popped up instantly and i went back. -Nah, you are lying, no problems now. No fault codes trough their obd reader.

So, had my friend plug in his newly bought BMW specific OBD2 reader and yes, 8 odd codes were present. Exhaust temp below freezing point and stuff.

Including strange readings from some sensors.

Drivetrain? Nah, no codes related to what i concidered to be drivetrain so i believed these problems was irrelevant since the issue SURELY seemed mechanical.

But anyway lets order all the sensors available and replace them all. Obviously some issues according to the fault codes anyway.

Opened the hood, removed the filter cover and started searching for sensors. Oh, i located one on the upper front right side of the engine, an exhaust pressure sensor near some silver cooling pipes. Tough one to get out, but wait... when disconnecting it, the cable for it seems... worn. In detail, it is actually worn through the cable isolation and one of the cables has rusted... completely off!

It has been rubbing against one of the aluminium pipes in its original cable routing.

So i cut both off. Soldered with shrinking tube and... yeah the entire drive train issue was forever gone aswell as the rest of the fault codes. This dead sensor had methastatic effects throughout the drivetrain even affecting the exhaust temp readings....

So banging nooces from the drive train? Check your sensors and the cables first. Took me 20minutes to fix and i would have saved ab. 2000dollars in local currency.

If finding any info anywhere about sensors having such odd effect that is...

[MauiM3Mania]

Moved to model specific discussion area.