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GENERATORCODES

Home / Generac / 1205

Evolution 1.0 / 2.0

1205

Overspeed, instantaneous

Engine · Alarm

Alarm 1205 is instantaneous overspeed: over the limit for 0.1 second (100 milliseconds). The table's 60 Hz figure is 75 Hz, and the 50 Hz figure is 62 Hz. It names the same stepper motor and mixer body causes as 1200.

Seen on: Air-cooled home standby generators with an Evolution 1.0 or 2.0 controller.

Likely causes

  • Stepper or mixer fault that lets engine speed spike, even briefly.
  • A throttle that is stuck open.

Checks an owner can do

  1. Do not restart the set to 'see if it does it again.'
  2. Record whether it happened at start or after it accepted load.

When to call a pro

Have a technician test the stepper and mixer. Instantaneous overspeed is an equipment-protection shutdown.

Source

Generac Diagnostic Repair Manual 10000041488 (Evolution 1.0/2.0 air-cooled). E-code rows below match that manual's alarm table as published by Home Generators for Sale and the manual text extracted from document 10000041488.

Wording follows that document. Firmware can change a threshold. If this page and the manual shipped with your unit disagree, follow the manual.

What fixed mine

No approved reports for this code yet. Send one. It stays in the review queue until it is approved.

Related Generac codes

https://generatorcodes.com/brand/generac/1205