Bad alternator can cause this as well.

Access the voltage readout in your OBC, check voltage with engine at idle. Also check voltage when holding the engine at around 2000 rpm for a minute or so. If you see voltage dipping down low your voltage reg or alternator are probably on their way out.

I had the same issue and replacing the alternator solved it for me.

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Current Bimmer
2004 X5 4.4i Sterling Grey Sport/Premium

Past Bimmers
1991 318I Alpine White
1995 740I Alpine White
1991 525I Schwartz
1998 323IS Scwartz
2004 330CI Cabrio Titanium Silver Metallic
1995 540I Schwartz
2000 Z4 3.0 Titanium Silver
2000 330ci Coupe Titanium Silver