Action in service

There are two different types of cases:

1. The fault is recognized by only one single control unit:

   Unplug the control unit and check the plug connection for dirt contamination, corrosion and mechanical damage.

   Check bus connections for short circuits and open circuits (loose contact).

   If the fault is a permanent fault and has appeared multiple times, and no problem with the bus connection can be found, replace the control unit.

2. A physical bus fault or a communications fault has been detected by multiple control units:

   Disconnect the plugs from all of the control units on the affected bus system, then inspect the plug connections for the individual control units (visual inspection for dirt contamination, corrosion, mechanical damage).

   Check bus connections for short circuits and open circuits (loose contact).

Then repair the plug connections and wiring as required and reconnect the plugs to the control units.

Examples:

corroded ground points.

Check rear area for water ingress (corroded plug connections).

Chafe marks on cables routed over sharp edges (e, g, below the seat or on the transmission tunnel).

Bus connection when retrofitting.