Code H66 - Yaskawa Error

Ensure any installed option cards are seated firmly in their connectors. Loose cards due to vibration are a frequent cause of communication faults.

A common point of confusion is that H66 appears even when the motor is running. If the cable is partially damaged, the motor might physically spin, but the drive sees "noise" or "no signal" and trips, leaving the motor coasting to a stop. Operators often claim, "The motor was running fine, then it just quit!" This confirms the issue is likely signal degradation, not a total mechanical seizure. yaskawa error code h66