hello friends, I have a problem with my BMW 330xi E46 that burns my brain. I need your help.

I did a cylinder head job on the car, it was perfect, later the front differential broke and it was changed without problem, but then I began to notice that I was running out of battery. even while it is working it holds up well. it cannot generate more than 12.3 volts. returning from the alignment service, park the car and it turns out that the starter is blocked. everything else seems to have no problems but when trying to start the vehicle the engine does not turn.

I tried changing the battery, but nothing. I removed the starter motor and it's ok. the starter exciter does not receive power, but from the contact plate it works correctly. Something is blocking the starter motor from turning but I can't figure out what it could be.

something that I have noticed is that next to the letter S of SPORT of the transmission. It doesn't tell me which gear is selected. P, R, N or D.

the codes I have on the scanner are:
000080: electrónica digital de motores (DME), EWS (sistema electrónico de inmovilización de vehículos). Transmisión/paridad

000080: Digital Engine Electronics (DME), EWS (Electronic Vehicle Immobilization System). transmission/parity.
000011: I don't remember the exact text. but it has to do with the engine oil level and temperature sensor.

please. Any information will be of great help to me.