Generac Error Codes: The Full List, What Each One Means, and How to Clear It

What the lights mean, and how to clear an alarm or a maintenance reminder on each controller: Generac lights and alarms. Next Generation (Power Zone 200) owners: these generators show alarms in Mobile Link and use a different code list, 502 to 7000. See Generac Next Gen error codes.

How to read the display and the lights

Evolution and Evolution 2.0 controllers (2013 and newer Guardians) show a four-digit code and a text message (on Evolution 2.0 the alarm log alternates them every five seconds), plus status LEDs. From Generac's own definitions:

• Alarm — solid red. Requires immediate attention; the unit shuts down or refuses to start. Clear it from the panel or press MANUAL to attempt a restart; if it returns, contact a dealer.
• Warning — yellow. Something needs attention but the unit still operates (charger warnings 2770/2780, for example).
• Maintenance reminder — yellow. Change oil, inspect battery, service due. It clears only after the maintenance is logged.

Nexus controllers (pre-2013) show text only, with no numbers — the numeric codes arrived with the Evolution controller in 2013. The functions map onto the numeric families below, but the exact wording and which alarms an owner can clear come from your own unit's manual: Generac's published code list covers the Evolution generations, not Nexus.

If the unit is enrolled in Mobile Link, the app's status history shows the code number and a one-line message; the messages are quoted in the table where Generac publishes them.

Portable generator? Generac portables use different lights and blink codes — see Generac portable generator fault codes.

The complete code table

Rows with links have a full page (meaning, reset, diagnosis, parts). Unlinked rows are on Generac's official list and will get their own page as we verify the manual text for each. Rows marked Next Generation come from Generac's Next Generation (Power Zone 200) code list and show in Mobile Link, not on a display; rows marked EcoGen 15 kW come from that unit's owner's manual and apply to it alone.

Severity: stop = unit will not run; warn = runs, needs attention. DIY: yes = owner can resolve with the manual; partial = owner-level checks first, then dealer; pro = dealer diagnosis from the start.

How to clear an alarm

Clearing an alarm is the same short key sequence for every code on a given controller, and it changes between controller generations rather than between codes. On Evolution and Sync controllers it is OFF, then ENTER, then AUTO; on Next Generation units, a three-second hold on OFF; Nexus and PowerPact have their own. Each code page says what must be true before its alarm will clear.

The full sequences, quoted from Generac's clearing article and the owner's manuals for each controller, together with the maintenance-reminder clear and what to do when an alarm will not clear or keeps coming back, are on one page: Generac lights and alarms. During an outage, Generac's restart article notes that a fault shows as a red status light and an error code on the control panel or in Mobile Link; if the unit runs in MANUAL but the house stays dark, the problem is on the transfer-switch side and a dealer is the next call.

A code and a symptom are not the same thing

A code is the controller's own account of why it stopped, and it is worth more than anything you can observe from outside: it names a condition Generac has defined, and the manual attaches an owner instruction to it. A symptom is what you saw, and on this equipment the same symptom covers several unrelated conditions. "It will not start" is a flat battery, a blown control-panel fuse, an open shutdown switch and an overcrank, and those four have nothing in common except the thing you noticed. So read the display first: if there is a number, use the table above and go to that code's page. Use the list below only when the display gives you nothing.

Symptoms without a code

Not every problem posts a number, and a unit with a dark display posts nothing at all. These are the cases where there is no code to look up, and the starting point is the symptom instead.

• Runs, but the house has no power. The generator is producing voltage (no 1900-series alarm) but the transfer switch didn't transfer, or its breaker is off. Check the generator's main breaker (on the unit) and the transfer switch — full walkthrough: Generac runs but no power. Never bridge this with a cord into a wall outlet — Generac's own page on backfeeding calls it illegal under the NEC and a lethal hazard to line workers.
• Starts, runs a few seconds, dies, no alarm. Watch the display on the next attempt — the alarm may post after the third or fourth try (RPM sense or low oil pressure).
• Didn't exercise this week. Check the exercise schedule in the menu, the yellow LED, and the battery.
• Yellow light with "Inspect Battery" / "Change Oil" text. That's a maintenance reminder. Do the service, then clear the reminder from the controller's maintenance menu (it will not clear from the alarm reset).
• Dead display, or nothing happens when the power goes out. Battery disconnected or dead; control panel fuse (0D7178T on 10–24 kW units); or the charger lost its T1 feed. Step by step: Generac won't start.

Maintenance that prevents most codes

From the 10–26 kW owner's manual: oil and filter at 25 hours, then every 2 years or 200 hours; air filter, spark plugs, and valve clearance every 4 years or 400 hours; battery inspection at every service. Most of the pages linked above end with "it was the battery" or "it was fuel supply." The details are on their own pages: oil type and capacity, maintenance kit by model, and battery replacement.

Sizing matters too. Underspeed (1600) and overload (2100) are not repairs, they're a generator that was never big enough for a well pump plus the AC. The wattage calculator shows what your essential loads add up to.