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

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 — overcrank, low oil pressure, RPM sensor failure, under-voltage, under-frequency — with no numbers. The functions map onto the numeric families below. If your Nexus manual says an alarm "cannot be cleared, call service dealer" (under-frequency is one), believe it.

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.

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.

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

Generac's general procedure for Guardian units with Evolution / Sync controllers, from its support article:

1. Confirm the external shutdown switch on the back panel is at I (closed). On 13 kW and larger units, check the internal switch too.
2. Press the red OFF button.
3. Press ENTER as prompted on the display. (The 1300 article says twice; some units prompt once.)
4. Press the green AUTO button.
5. To test, press the blue MANUAL button.

Variants:

• PowerPact 7.5 kW: press OFF twice to reach an active alarm; three times if a maintenance reminder is also showing.
• Next Generation (Power Zone 200): hold OFF for 3 seconds, then AUTO.
• Nexus: rocker switch to OFF, ENTER twice, rocker to AUTO. Units without a rocker: OFF button, ENTER twice.
• Liquid-cooled (Power Zone 410): STOP + ENTER, per Generac's article — the code table above is for air-cooled units only.

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; clear it with the sequence above and return the unit to AUTO. If it runs in MANUAL but the house stays dark, the problem is on the transfer-switch side and a dealer is the next call.

Symptoms without a code

Not every problem posts a number.

• 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. 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. Battery disconnected or dead; control panel fuse (0D7178T on 10–24 kW units); or the charger's house breaker tripped.

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 yearly. Most of the pages linked above end with "it was the battery" or "it was fuel supply," and both are on the yearly checklist.

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.