History Diagnostic Trouble Codes (DTCs)

When a DTC reports a failure and the failure was not in the current ignition cycle the DTC will be stored as a History code. The IPC performs internal diagnostic tests in order to acknowledge that the related systems have reported a pass or fail condition. Each diagnostic test that fails is recorded in the IPC memory. The IPC memory can be accessed with a scan tool to determine which DTC circuit was at fault. A history DTC can be cleared (for any diagnostic test) as follows:
- Completing 100 subsequent ignition cycles with no diagnostic test reporting a fail.
- Using a scan tool.
- Disconnecting the battery.
- Disconnecting the IPC connector.