Open load on door motor brake 1 output
Check the faulty component, cable harness and connectors for mechanical damage. If the resistance measured over the coil of the brake component (when disconnected from the DCU) is higher than approximately 200 kohm the DCU will not detect that it is connected, thus there is open load.
What you'll see
The door leaf cannot be run by the DCU since the brake stays applied. If the emergency opening system is activated, the door can be moved by hand or slide open by itself.
System reaction
The DCU signals 'Major fault' over CAN to MBS, which then requests 'Door malfunction' notification and an exclamation mark indication in the related door in Bus stop page in ICL.
Diagnostic depth
A current below normal operating level has been detected on the high-side output for the brake.
- Open circuit due to damaged or broken wires. - The connected component is out of order.