As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WASTEGATE ACTUATOR FAILS CAUSING ECU OVERBOOST FAIL CODES. WHEN THE ACTUATOR IS PRESSURE TESTED IT IS FOUND TO LEAK AIR DUE TO A LEAKING DIAPHRAGM. ACROSS A FLEET OF NINE DA40NGS AND DA42NGS ABOUT 25 OF THESE ACTUATORS HAVE NEEDED TO BE REPLACED OVER THE PAST 2 YEARS. THEY ONLY SEEM TO LAST 100-300HRS ROUGHLY.