Description: Mercedes benz dtc p029921May 18, 2021 · Hooked up and ODB scanner and got an errorcode P029921 while the car was in limp mode. "The boost pressure of turbocharger 1 is too low. The signal amplitude is less than the minimum amplitude". So a little troubleshooting. I can recreate the error. It usually happens at 80+ km/h/50+ mph, at low revs, 7. gear, constant speed, uphill.
Mercedes benz dtc p029921