Miller Millermatic 355 Owner's Manual page 64

CAN Data Version Incompatible
OM-288360 Page 60
Depressed trigger on spool gun.
The UI and the Control are not compatible, per-
haps due to a partial firmware upgrade.
Do not pull trigger on spool gun. Depress trigger
on MIG gun to clear error.
Disable Locks and Limits.
Contact Miller Electric authorized service
location
Restart the Firmware upgrade process.
Contact Miller Electric Mfg. authorized service
location.