>start DCS !
Door Check Sequence Not Operational Yet
Otis · GAA21750AK3 Service Tool
What does >start DCS ! mean?
This blinking event message indicates that the Door Check Sequence (DCS) for the OTIS 2000 Controllers MCS120/MCS220 has not yet been performed or is not fully operational, consequently blocking elevator movement. The DCS is a critical safety verification for hoistway door contacts.
Common Causes
- The Door Check Sequence has not been initiated since the last power cycle or system setup.
- The DCS was interrupted or failed to complete successfully.
- Incorrect configuration settings preventing the DCS from running.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Initiate the Door Check Sequence (DCS) through the GAA21750AK3 service tool menu (SETUP > DCS Run).
- 2
Monitor the DCS progress and address any specific door errors displayed during the sequence.
- 3
Ensure all door safety contacts are correctly installed and wired before starting the DCS.
Verified technical data. Last updated: March 2026
Related Faults
Source: Otis GAA21750AK3 Service Tool