A friend has an old Astra wagon, and the central locking stopped working. I just got a cheap Chinesium scantool that happens to cover this model, so got a code readout, and it returned U0009 For Opel cars, this means:
High Speed CAN Communication Bus (-) shorted to Bus (+)
If that is so, shouldn't it cause a lot more problems? Nothing else seems to be wrong with the old clunker. So I guess it only affects communication between 2 modules either side of the shorted cable.