Open circuit on closed position limit switch 1
Check the microswitch, cable harness and connectors for damage. The voltage on the DCU input pin shall be approximately 24V (system supply voltage) when the door is completely closed and 0V (ground) otherwise. When the door is completely closed the microswitch shall be actuated by the door mechanism.
What you'll see
The door leaf cannot be run by the DCU as it has lost closed position of door. 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
The voltage measured on the tri-state input pin indicates open load. This happens when the input voltage is between approximately 8 V and 16 V with a supply voltage of 24 V to the DCU.
- Open circuit due to damaged or broken wires. - A connector is unplugged. - The component is out of order. - DCU output Peripheral supply is out of order.