Cause: Tuning error comes when auto-tuning failed. This fault specifically occurs when the drive's motor autotuning (also known as auto-tuning or auto-setting) process fails or encounters an issue. 

er7 fault in fuji FRENIC MEGA drive indicates Tuning error. This means the drive failed during auto-tuning of the motor, typically when attempting to identify motor parameters or perform vector control tuning.

• Verify Motor Nameplate Data in Drive Parameters.
• Check Motor Wiring.
• Ensure Motor is Uncoupled/Freely Rotating (if required).
• Select the Correct Autotuning Mode.
• Re-attempt Autotuning.