Fuel injection system programming (Audi A4 B6)

When the battery or the plug of the control unit is disconnected, all parameters that are determined during the self-learning of the system are erased. These parameters include the parameters of idle speed, partial or full load, deceleration. As a result, when the battery is reconnected, interruptions and misfires during acceleration, as well as uneven engine operation in idle mode, may occur. Therefore, before starting the engine, turn on the ignition for ten seconds! Even during a short test drive, the control unit is re-learned and adapts to the engine parameters.

However, if a permanent fault code is recorded in the recorder, the learning process may be blocked. In this case, it is necessary to first read and erase the fault recorder data (in the workshop). A sporadic, i.e. non-permanent fault is, by the way, erased. Automatic erasure occurs if the fault does not reoccur within 40 engine warm-up phases (engine start at coolant temperature below 50°C, shutdown at temperature above 72°C). If after troubleshooting, repair or checking individual parts the engine starts but stalls after a while, the reason may be that the control device is blocked by the anti-theft device. In this case, the control device may also need to be matched.

The text is based on materials from the website: AUDImanual