Computers and Control Systems: Description and Operation

The Multiport Fuel Injection (MFI) system is equipped with an Engine Control Module (ECM) -J220- with On Board Diagnostic (OBD) capability.

When malfunctions occur in sensors or components monitored by OBD, Diagnostic Trouble Codes (DTC) are stored in DTC memory.

Stored DTCs are identified using the VAG1551 Scan Tool (ST).

After the necessary repairs are completed, DTC memory must be erased.

OBD II legal regulations require a display (readiness code) that shows inspection readiness for the annual exhaust emissions test. The readiness code shows that every component and/or system that affects exhaust emissions, which can lead to the Malfunction Indicator Lamp (MIL) being switched on, has been operated at least once with positive results.

The readiness code is reset and/or erased and must be regenerated every time DTC memory is erased, the power supply to the ECM -J220- is interrupted (example: when connecting test box VAG1598/19), or the battery has been disconnected. Readiness Code, Generating