99
REVERSED TACH FAULT
Otis · DSD 412 Elevator System
What does 99 mean?
The digital encoder signals and motor voltage signals do not agree in their detected direction of rotation.
Common Causes
- Encoder leads are reversed.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Reverse the connections for encoder phases A and A/NOT.
Verified technical data. Last updated: March 2026
Related Faults
Source: Otis DSD 412 Elevator System