OBD II Memory Functions

The J220 Engine Control Module (ECM) for the Fuel injection and Ignition Systems is equipped with a Diagnostic Trouble Code (DTC) memory.

If malfunctions occur in monitored sensors and components, the malfunction will be stored in the DTC memory together with a text message describing the type of malfunction.

Malfunctions which only occur sporadically will have the additional description: "sporadic malfunction" shown on the print out. This type of malfunction is identified in the displays by /SP. The cause of /SP malfunctions for example, could be a loose terminal or intermittent open circuit. If the /SP malfunction does not occur again within 40 engine starts, it will be erased from DTC memory.

Stored malfunctions (DTC's) can be displayed once DTC memory has been checked. See 'Testing and Inspection, Procedures.' Testing and Inspection

DTC memory must be erased once malfunctions have been eliminated. See 'Testing and Inspection, Procedures.' Testing and Inspection

The Readiness code must be created again each time DTC memory is erased or when the Engine Control Module (ECM) voltage supply is interrupted. See 'Testing and Inspection, Procedures, Address word 01.' Testing and Inspection