When operating a control point to open the trunk lid or the tailgate, the trunk lock unlocks, but there is no actuation of
the trunk control/tailgate control drive unit (M51/3).
Faulty microswitch signal of trunk lock.
In the event of a problem, the status of the trunk lock (picture 1) does not change during opening/closing of the trunk
lid or tailgate.
The function of the interior trunk release is not affected.
Replace trunk lock (A85/5).