9E0004 Mercedes Fault Code :
Read the description of 9E0004 in ACM02T and the engine lights up for ACM02T - Exhaust aftertreatment (17A03) code, there are some possible causes for it.
The signal line (circuit 15) to control unit '17A03 (Exhaust aftertreatment control unit (ACM))' has an open circuit or short circuit to ground.