Permanent Diagnostic Trouble Code (Permanent DTC)

Permanent DTC is defined in SAE J1979/ISO 15031-5 Service $0A. ECM stores a DTC issuing a command of turning on MIL as a permanent DTC and keeps storing the DTC as a permanent DTC until ECM judges that there is no presence of malfunction. Permanent DTCs cannot be erased by using the Erase function of SDT or Generic Scan Tool (GST) and by disconnecting the battery to shut off power to ECM. This prevents a vehicle from passing the state emission inspection without repairing a malfunctioning part. When not passing the state emission inspection due to more than one permanent DTC, permanent DTCs should be erased, referring to this manual.

NOTE:

The important items in state emission inspection are that MIL is not ON, SRT test items are set, and permanent DTCs are not included.
Permanent DTCs do not apply for regions that permanent DTCs are not regulated by law.