Permanent Diagnostic Trouble Code (DTC)

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2010 Mercury Milan, 2010 Mercury Mariner, 2010 Mercury Grand Marquis, 2010 Lincoln Town Car, and 2010 Lincoln Navigator L. However, it is still accessible from the selected car via links, so may be relevant.

The software stores a permanent DTC in non-volatile random access memory (NVRAM) whenever a DTC is set and the MIL has been illuminated. Permanent DTCs can only be cleared by the module strategy itself. After a permanent DTC is stored, 3 consecutive test passed monitoring cycles must complete before the permanent DTC can be erased. The PCM clears the permanent DTCs after one monitoring cycle if a request to clear DTCs is sent by the scan tool and the test subsequently runs and passes. A permanent DTC cannot be erased by clearing the KAM. The intended use of the permanent DTC is to prevent vehicles from passing an in-use inspection simply by disconnecting the battery or clearing the DTCs with a scan tool prior to the inspection. The presence of the permanent DTCs at an inspection without the MIL illuminated is an indication that a correct repair was not verified by the on-board monitoring system.