Z3M MSS50 DTC 155

[isma_s54]

Hi everyone,

After several low battery voltage / weak start issues, I’m now getting the following fault on my BMW with MSS50:

DTC 155 – MSS50 Control Module Fault Memory Master

The car still runs, but the fault keeps coming back.

I’m thinking about trying a WinKFP ECU update in case the software got corrupted because of the voltage drops.

Has anyone here already had this issue?
Did a software update fix it, or did it end up being a hardware/power supply/DME issue?

Thanks in advance for any feedback.

[MpowerE36]

Hi,

I've already had this problem and it is a hardware issue (cpu issue from my point of view).

[isma_s54]

Thanks for your feedback.
So from your experience, do you think the DME/ECU needs to be completely replaced, or is there still a chance to repair it (CPU repair/rework)?




I’m trying to understand if it’s usually recoverable before looking for another MSS50 unit.

[MpowerE36]

I would try to replace the master cpu then if it doesn't work I would buy another one. Be careful with companies which "repair" this issue. They only disable dtc in the software which not solves the root cause of the problem.