History DTC

After a DTC has been set, IPC continues to monitor for test and failure conditions. For most DTCs, if test conditions are true and failure conditions are false, DTC is changed to HISTORY. Some DTCs require test conditions to be true and failure false several times or require an ignition cycle to change from CURRENT to HISTORY. If there are no CURRENT DTCs for 50 ignition cycles, all HISTORY DTCs will be cleared.