I am replacing the MAF sensors (P2553-001 Monitoring of mean quantity adaption Plausibility of Learning value too large and P2633-001 MAF sensor drift offset drift under engine load) and what know if a reset is necessary or will the car learn on its own?
How to reset it without a STAR scanner?

Also where is the transmission thermostat. Scanner has short to positive P2520-001

Dave
2009 e320 bluetec.

 

Regarding an ECU reset, pulling the negative battery cable off its terminal for ~10 minutes will reset all adaptations.
That would be my advice.

 

Replacing the mass airflow sensor on this engine will require access to Xentry/DAS. First you need to clear the fault memory and then go into engine module>adaptations>teach in. Removing the battery power will not do any of this.