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ErrorLib — Industrial Fault Code Library

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Critical Mech

Critical Vend Mechanism Error

Otis · 400 Elevator

What does Critical Mech mean?

Indicates a critical vend mechanism error has occurred, specifically that the DMC home sensor has malfunctioned. This sensor is crucial for the proper positioning and operation of the dispenser mechanism, and its failure will prevent vending.

Common Causes

  • Malfunction of the DMC home sensor.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Inspect the DMC home sensor for physical damage, misalignment, or obstructions.

  2. 2

    Inspect all wiring and connectors associated with the DMC home sensor for loose connections, damage, or corrosion.

  3. 3

    Measure the supply voltage at the DMC home sensor terminals against the manufacturer's specifications.

  4. 4

    Check the elevator's control system diagnostics for the current status of the DMC home sensor input.

Browse all codes in this manual (41)
Verified technical data. Last updated: April 2026

Related Faults

Bill JamBill JamBill MotorBill Validator Motor DefectiveBill SensorBill Sensor Error
Source: Otis 400 Elevator
Open Manual (Page 43)Search more codes in this manual