The diagnostic trouble codes (DTCs) are grouped into several types. Each type has a unique set of characteristics for the malfunction indicator lamp (MIL) operation, the DTC storage, and the DTC clearing. The following contains a brief summary of the type and the associated properties of each:

Type C is non-emissions related, does not turn on the MIL, but may turn ON an auxiliary service lamp if the vehicle is so equipped. The DTC stores at the time of the first fail.