Note: Special devices are required for systematic troubleshooting and troubleshooting. Such devices are very expensive and are usually only available at service stations. Therefore, only general checks are described below.
1. Check the condition of the battery (see Chapters Routine care and maintenance and Engine electrical systems).
2. Check the condition of all fuses (see Chapter On-board electrical equipment).
3. Disconnect and reconnect all connectors of the relevant electronic systems. Check that the connectors and cables are securely fastened in the engine compartment.
4. Check the reliability of all ground connections.
5. Check the tightness of hoses and pipelines, paying special attention to detecting cracks. Replace defective components, tighten loose nipple connectors.