Diagnostic Trouble Codes (DTCs)

Diagnostic Trouble Codes (DTCs) when set, indicate that the IPC has detected a malfunction in a particular circuit or other system. The IPC is programmed with routines for internal checks that it follows only under prescribed conditions (Test Conditions). When these conditions exist, the IPC checks certain circuits or systems for a malfunction (Failure Conditions). When the failure conditions are true, a DTC is set current. Some DTCs command that the IPC illuminate the Service Vehicle Soon indicator.

Diagnostic Trouble Codes are not stored in the IPC's EEPROM and therefore, are not retained after a battery disconnect.