Generac generator code 1100
High severity — The controller tried to crank the engine through its full attempt sequence (typically up to 10 tries) and never detected a run signal, so it locked out with an Overcrank alarm.
Applies to: Guardian/Protector series air-cooled and liquid-cooled standby generators with an Evolution or Nexus controller (roughly 2004–present)
What it means
Picture the scene: the automatic transfer switch calls for power, the engine turns over on the starter, and it keeps turning over — attempt after attempt — without ever catching and settling into a run. After the last attempt in that sequence fails, the Evolution or Nexus display stops cycling and parks on "1100," usually with a red alert light and an audible alarm if one's wired in. The unit won't try again on its own; it's waiting for a person to clear the fault.
The controller tried to crank the engine through its full attempt sequence (typically up to 10 tries) and never detected a run signal, so it locked out with an Overcrank alarm.
Overcrank is a symptom code, not a diagnosis — it just confirms the engine never fired. The actual cause sits somewhere in the fuel, spark, or compression chain, and which one it is often comes down to whether the engine cranked strongly the whole time or seemed to labor.
Most common causes
Roughly in order of how often each one turns out to be the culprit:
- Empty or shut-off fuel supply (closed LP/NG valve, empty LP tank, or stale gasoline)
- Clogged fuel filter or fuel line
- Weak, sulfated, or dead 12V starting battery
- Fouled, worn, or incorrectly gapped spark plug(s)
- Faulty ignition coil, fuel-pressure regulator, or carburetor/stepper-motor assembly
- Low compression from an overdue valve adjustment
What you can check yourself
Work through these before assuming the worst — most 1100 calls trace back to the first two items:
- Confirm the fuel valve is fully open and the LP tank or natural gas supply is actually on
- Check battery voltage at rest with a multimeter (a healthy 12V battery reads about 12.4–12.7V) and clean any corroded terminals
- Press the controller's OFF button, wait a few seconds, then AUTO to clear the alarm before trying a manual start
- For gasoline units, pull the spark plug(s) and check for fouling or a wet/flooded cylinder
- Note whether the unit cranks strongly (points to fuel/ignition) or cranks weakly (points to battery)
- If you smell raw gasoline or LP/natural gas while the engine cranks, stop immediately — do not attempt another manual start.
- Never crank a generator repeatedly in a closed garage or shed; exhaust carbon monoxide builds up fast and has no smell of its own.
All codes for this brand
Every Generac generator fault code — full list with what differs between models.
Related codes and symptoms
- Generac 1501/1505/1511/1515 — RPM sensor loss, the code that shows up when 1100's usual suspects are ruled out but the engine still won't confirm it's turning
- Generac Low Battery warning, worth checking first since a marginal battery is a frequent overcrank contributor
- Generac code 1300 — Low oil pressure, another Evolution/Nexus shutdown that gets triggered during or right after a start attempt
- Symptom: Generator Won't Start — broader troubleshooting if you're not sure the code on your display is really 1100