Check EGR cooler visually eg with an endoscope . If you find a fault with the EGR cooler , investigate the cause of the failure eg caused by too much soot from the engine or leaking coolant in the cooler Make sure the EGR valve can move freely and closes properly Check the boost pressure sensor ( T122 ) with ignition on and engine off To check if the MAF adaptation may be incorrect : - Check for leaks between the mass air flow sensor ( T126 ) and the compressor - Check the mass air flow sensor T126 , exhaust pressure sensor T125 , boost pressure sensor T122 and boost temperature sensor T121 . Check the turbocharger and its motor - use SDP3 's condition test for variable turbochargers Check the exhaust system for leaks between the turbine and muffler Check for error codes related to the injectors Check the engine oil consumption, for example, if there are leaks in the turbocharger. Gas engine: Check throttle M34 Check the dump valves V189, V190, and the control for these works Check wastegate valve V109 and boost pressure sensor T47. Note Always perform a reset of adaptation values ​​of the mass air flow sensor , if the mass air flow sensor is replaced, or if a leak in the air intake system have been fixed To verify that the error is fixed requires driving with a full load for a few minutes

Diagnostic depth