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ErrorLib — Industrial Fault Code Library

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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. 1

    Reverse the connections for encoder phases A and A/NOT.

Browse all codes in this manual (57)
Verified technical data. Last updated: April 2026

Related Faults

117/118SERIAL COMMUNICATION FAULT400MOTOR OVERLOAD FAULT401EXCESSIVE FIELD CURRENT
Source: Otis DSD 412 Elevator System
Open Manual (Page 87)Search more codes in this manual