[adamosak]

Hello, i have a 2005 e90 and i’m running into issues with voltage. While driving, the speedo werirdly fluctuates and sometimes just drops to 0 and back, with DSC and brake warnings appearing along with flat tyre, abs logo etc. In the dashboard “secret menu” the voltage jumps to 17v right before the warning lights appear. This sometimes happens 5 times in 30s and then doesn’t appear for another hour. ISTA shows a bunch of codes, everything caused by overvoltage.

Battery is low, idle is 12.1V and running 13.8V.

Don’t know if it’s the battery or the alternator, or whatever.

Thanks

[jbash87]

Voltage regulator, most likely. Similar issue w/ my E60 and swapping that out has solved it.

[adamosak]

Originally Posted by jbash87

Voltage regulator, most likely. Similar issue w/ my E60 and swapping that out has solved it.

Thanks, is it hard to DIY for someone with pretty basic knowledge? And does it come alone or is it the whole alternator to be replaced

[jbash87]

Originally Posted by adamosak

Thanks, is it hard to DIY for someone with pretty basic knowledge? And does it come alone or is it the whole alternator to be replaced

No idea on the e90s honestly. What's the last 7 of your VIN? I can check the maintenance manual and post screen shots.

[adamosak]

Originally Posted by jbash87

No idea on the e90s honestly. What's the last 7 of your VIN? I can check the maintenance manual and post screen shots.

VB22023
Appreciate it a lot

[jbash87]

Looks like the alternator is on top for your motor, correct? Should be a VERY easy replacement.

Here is the part number reference with a exploded view of the parts.
https://www.realoem.com/bmw/enUS/sho...diagId=12_1245

Make sure to remove the negative battery terminal before you start any work. Then just remove and replace.

[adamosak]

Originally Posted by jbash87

Looks like the alternator is on top for your motor, correct? Should be a VERY easy replacement.

Here is the part number reference with a exploded view of the parts.
https://www.realoem.com/bmw/enUS/sho...diagId=12_1245

Make sure to remove the negative battery terminal before you start any work. Then just remove and replace.

Thanks a lot.
https://youtu.be/nif18xR-Fpk?si=7e_QG595TnHt1ewd
Just found this video, exactly what my car does, only that the speedo doesn’t stay at 0 for so long.
Author says it fixed the issue, so I’ll look where i can order one in my country

[jbash87]

Originally Posted by adamosak

Thanks a lot.
https://youtu.be/nif18xR-Fpk?si=7e_QG595TnHt1ewd
Just found this video, exactly what my car does, only that the speedo doesn’t stay at 0 for so long.
Author says it fixed the issue, so I’ll look where i can order one in my country

Be sure to post back with the results. Good luck!

[adamosak]

Originally Posted by jbash87

Be sure to post back with the results. Good luck!

Voltage regulator seems to have fixed the issue, haven’t had a problem for 3 days right now, so i’m pretty sure you were right.
Thanks a lot!