Instrument cluster
 

Today when I start the engine the dashboard did not work.
Diesel manometer, manometer temperature, rpm, speedometer, on board computer and has kilometers. I turned the engine off and then on, it was all the same and I diceded continued the trip.
30 minutes later I stopped the car, when I returned and started again the everything was normal.
What can be the symptom?:dunno:

BMWs are very sensitive to abnormal voltage.

If the battery is low, the alternator is malfunctioning or the battery is going bad symptoms as you describe can happen. I would check the battery first by having it load tested. If the battery is good have the alternator checked. If the battery is good it could have been low and as such a one time thing, just a low battery. If battery was low but checks good, it is important to know why the battery was low as there could be a problem elsewhere that is core cause.

Sorry to respond so today, but yesterday is that I was able to complete the tests.
I do not know what to think, I performed a test battery and alternator, and it was not bad.
I have 12.3 and 14.3 volts running.

If it dips below 13 volts running I would think that might be an alternator problem.

12.3 can happen. If you tach it up and it fall back to an idle the charge will fall to lower than 13 but should recover very quickly to an acceptable range.

Did you test the battery with a load test?

When you tested the alternator was the air and lights and some other stuff on that draws juice, with X at idle for a time to see what it reads and see if the voltage bounces around?

Not implying your tests were not conclusive, just want to understand what you did.