Fault code generation: Notes

Fuel level, reasonability diagnosis:  Because fuel level is used as an enable criterion in certain diagnoses, the control module must know that the fuel level value is reasonable. This occurs in the following manner; Trionic receives the bus message "Fuel level XX liters" from the MIU. Trionic monitors the value and knows that the fuel level value should sink while the car is being driven. There are several value filters in Trionic which help to avoid discrepancies such as sloshing in the tank or starting on a hill. The fuel level diagnosis can be seen as a support diagnosis; it reports no diagnostic trouble code but P0455 is normally set if the tank seal diagnosis reports a large leak for example. If, however, the tank seal diagnosis has reported the same fault at the same time as the fuel level diagnosis has reported a fault, P1455 is set instead.

P0455, P1455 are set if faults are reported during Phase B

P0442, P0456, P1442 or P1456 are set if faults are reported during Phase C.