E61 525d electrical issues

[cherr]

Hello everyone. first post here for an issue i cant seem to find a solution for.

Long story short - when starting the car, DBC, FTM, DSC and start assistant appears, as well as fault in drive.

Previously this was intermittent, and the codes would appear only after the car sat overnight - after driving for 15-20mins, restarting the car would fix it.

Lately there were more symptoms: one day the idrive went completely haywire - Control systems fault, servotronics, leveling system fault. the speedo would read zero + no powersteering, aswell as wipers would stay on. restart would fix these faults

After reading numerous posts here and having 3 independent mechanics check the issue the following stuff was done:

• New voltage regulator
• 95ah agm battery (correctly coded and registered)
• Tried different dsc unit, the same issue persisted and switched back

now the fun part: for the last few days, everytime I start the car the dbc,dsc errors always appear, as well as fault in drive. restarting the car has no effect whatsoever. If i keep the rpms above 1k? (eg. the car is not idling), the fault in drive dissapears. when idling, the headlights are twitching, aswell as interior lights get dimmer when returning to idle. Not very noticable but its there

From ista I see that when Idling, the dsc sometimes doesnt communicate - reading steering angle sensors, it sometimes freezes and shows no data available, but if i give the car gas an keep rpms a bit higher, there are no problems reading the sensor data.

hidden menu 9 voltage: 14.7 when idling (seems pretty high for a fresh battery?), this keeps steady whilst i rev the engine. after i let of the gas and RPMs go down to idle, the voltage drops to 13.5 shoots to 15.1, and then stabilizes at 14.7, (now the trans fault appears in idrive and dsc module readings start to freeze/become unavailabe)

one more fact is that after the car is shut off, the voltage after 5 minutes is already 12.1v - it was the same as with the previous battery, which I thought just wasnt holding charge/had internal resistance. seems like its not the case

Car always starts normally and cranks pretty fast

no water was in the battery compartment/trunk


could these symptoms be caused by a bad ground somewhere? which spots should I check besides the main engine ground? could it be something else?

attached errors from ista