Nest thermostat: M6 or N412: your system needs maintenance
There is a problem with your heating and cooling system itself, not the thermostat.
Applies to: Nest Learning Thermostat, Nest Thermostat E and Nest Thermostat. What you see: a code.
Codes this page covers: M6 N412.
What Google says to do
- Google says to contact a pro to service your system and fix the issue.
Source
Google’s own help page, read on the date shown.
- Google Nest Help: Troubleshoot Nest thermostat help codes — Nest Learning Thermostat (1st to 4th gen), Nest Thermostat E and Nest Thermostat; H codes only where a Heat Link is installed. support.google.com Checked 2026-09-29.