Hello all.

I have a 2008 535i which was experiencing an overvoltage due to a faulty voltage regulator. Before replacing the regulator, the car would shut down all electronics to prevent anything from being fried. As expected, the car would display every warning light possible since everything was shut down.

I have since replaced the voltage regulator, and the car is now back to normal (and within proper voltage) with a few exceptions. All of the electronics are working properly except the active body control (suspension feels horrible and rough), brakes (feel super squishy), active handling (steering wheel feels horrible), transmission, (shifting feels horrible and is difficult to get into gear). Engine is running normally.

The car is displaying no error messages, so it isn’t detecting that something is wrong with the car. There is also no check engine light.

I have checked all fuses in the trunk and under the dash and have replaced the charging relay. I also had the battery health checked.

Is there something I’m missing? Are there fuses associated with the ECU that could have been blown during overvoltage? And if there are, wouldn’t the computer displaying that active body control, transmission etc aren’t working properly?

Regards,

Van

 

hello did you ever fix the problems? please let me know my car did everything you explained last night i have a spare alternator but did you figure out the transmission problems and everything else?thank you

 

The OP probably will not respond because they haven't been on here since that post. What are you using to troubleshoot the issue. If you do not have BMW software tools I would advise you to get it so you can see what's going on. The circuit counter may be exceeded and need to be reset but that can not be done without the software. If a battery disconnect for 1hr does not fix the problem I'm pretty the the counter needs to reset or module reinitialized.

 

i used a scan tool not sure what kind exactly but jus about a code for every module when the car had no check engine light before dtc, steering rack,shifter ect had a code for overvoltage the transmission malfunctions pops up on dash and i drive i turned the car on in park to live read the data off the scanner the the battery was charging at 12 volts with the car on so i’m not sure could you point me in a direction to the software you speak of?im sure the car needs an alternator jus wondering what the problem might be mainly for the transmission thank you

 

First resolve the over-voltage issue.