General Repair Information

When performing work where there is a danger of an electrical short circuit, disconnect the earth cable from the battery. The following procedure must be observed to avoid injury to persons and damage to sensitive electrical components:
- The battery terminals must be covered so that accidental contact does not occur because the battery cable has gradually moved backwards. This also prevents accidental contact during assembly, e.g. with bright metal components or tools.
- If individual connection cables forming part of the battery connection have to be dismantled, always remove the earth clip on the battery terminal first so that all the power circuits on the vehicle are free from voltage. Non-adherence to this ruling can lead to electronic components being damaged. Reconnection takes place in reverse order, the earth clip is the last to be connected to the battery.
Never connect/disconnect control unit or miscellaneous electronic component wiring harness plugs with the ignition switched on to avoid damaging the control units.
Never pull on cable when disconnecting wiring harness plugs. Carefully release locking mechanism at wiring harness plug.
When cleaning and contact sprays are being used, the manufacturer's recommendations must be followed. Improper use can damage sensitive electrical and electronic components.
When returning a unit containing a CD unit (e.g. navigation control unit, CD changer), remove all CD's to avoid damage to the laser head or CD.
Disconnect the battery from the on-board power supply before charging or rapid charging. Never start the vehicle using a rapid charger. Overvoltage in the electrical system can damage control units.
When programming the control unit memory system, ensure that no persons are present in the interior - risk of injury!
After completing repair operations, ensure that wiring harness connections and battery connections are correctly seated and that ground connections have been made correctly. Defective electrical connections cause functional problems and destroy control units.
Wiring harnesses and wiring troughs which are released or removed during repair work must be refastened in their original positions using genuine Aftersales parts (cable ties, clips, wiring trough brackets, etc.).
Disconnecting the ground cable from the battery automatically erases the contents of certain electronic system memories (e.g. electric window winder, time and date). After reconnecting the ground cable to the battery, these volatile memories must be reprogrammed and audio equipment decoded.