General notes on ignition system
WARNING: This page is about a different car, the 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
- The battery must only be disconnected and connected with the ignition switched off since the Engine Control Module (ECM) can otherwise be damaged.
- For the electrical components to work properly, a voltage of at least 12.7 V is required.
- It is possible that the control module will recognize a malfunction and store a DTC during some tests. After completing all tests and repairs, DTC memory should therefore be checked and erased if necessary.
- If the engine only starts briefly and then turns off again after troubleshooting, repair or checking of the components, it may be that the immobilizer is blocking the Engine Control Module (ECM). DTC memory must then be checked and if necessary, control module must be adapted.
CAUTION:
- Safety precautions before disconnecting battery:
- The battery must only be disconnected and connected with the ignition switched off since the Engine Control Module (ECM) can otherwise be damaged.