Generac Error Codes: Full List with Meanings and Fixes

This guide covers the Generac error codes that Generac publishes for its air-cooled home standby generators (made by Generac Power Systems). Codes and exact sub-codes can differ by controller generation, so always compare the number on your screen with your owner’s manual. For deeper help on a single code, follow the “Full guide” links below.

Generac error codes list

Here is the master list of Generac error codes and warnings that Generac documents on its US support site. Ranges such as 1900–1906 mean every number in that range has the same name and the same owner checks.

Code	Meaning	Quick fix	Full guide
1000–1006	Controller fault (Next Generation series)	Clear alarm once; call a dealer if it returns	—
1100, 1101	Overcrank: engine cranks but will not start	Open fuel valve, check fuel setting and LP level	Generac 1100 guide
1200–1208	Overspeed: engine ran too fast	Clear alarm; call a dealer	—
1300	Low oil pressure	Check oil level and top off	Generac 1300 guide
1400, 1401	High temperature	Clear blocked intake and exhaust, let cool	—
1501	RPM sensor loss	Check battery and cables, fuel valve, loads	Generac 1501 guide
1505	RPM sensor loss	Check battery and cables, fuel valve, fuel setting	Generac 1505 guide
Other 1500–1522	RPM sensor loss	Same checks as 1501 and 1505	—
1600–1603	Underspeed: engine running too slow	Remove loads, check fuel and air filter	Generac 1600 guide
1800, 1801	Overvoltage	Clear alarm; call a dealer	—
1902	Undervoltage	Check fuel setting, LP level, air filter, loads	Generac 1902 guide
Other 1900–1907	Undervoltage	Same checks as 1902	—
2098, 2099	Wiring error / transfer wire warning	Call a dealer	—
2100–2103	Overload, remove load	Turn off non-essential loads, clear, restart	—
2750	Low battery	Check battery voltage, let it charge, replace	—
2751	Very low battery	Same as 2750	—
2760	Battery problem	Inspect or replace battery	—
2770	Charger warning	Replace weak battery; dealer for fuse or circuit	—
2780	Charger missing AC	Call a dealer (charger power circuit)	—
2800, 2801	Auxiliary shutdown or E-stop switch open	Set shutdown switches to ON (I), clear alarm	Generac 2800 guide
3217	Low fuel pressure (yellow)	Check fuel valve and LP level; dealer for pressure test	—
5415–5417	Engine oil level (Next Generation)	Check and add or drain oil, restart	—
7000	Overload cooldown (Next Generation)	Reduce loads; dealer if it persists	—
Schedule A/B/C	Maintenance reminder (yellow)	Do the scheduled service	—
Inspect Battery	Maintenance reminder (yellow)	Inspect battery and terminals	—

Generac’s own dealer list says most of these codes go beyond typical DIY repair. The owner’s job is to do the safe outside checks, clear the alarm once, and try a manual start.

What do the red and yellow lights on a Generac generator mean?

A red light means an alarm, and the generator has shut down or will not run. A yellow light means a warning or a maintenance reminder, and the generator may still run. Green means the unit is ready in AUTO.

• Red (alarm): Overcrank, low oil pressure, high temperature, RPM sensor loss, underspeed, undervoltage, overload, low battery and auxiliary shutdown.
• Yellow (warning): Charger warning, charger missing AC, low fuel pressure, inspect battery and scheduled maintenance.

Generac notes that warnings must be fixed before the message goes away. Maintenance reminders can be dismissed after the service is done.

What do Generac starting and cranking codes mean?

Starting codes mean the engine either did not turn over correctly or turned over and never ran. On Generac units, these are mainly the 1100 and 1500-series codes. Fuel and battery problems cause most of them.

1100 and 1101: Overcrank

Overcrank means the engine cranked but would not start, so the controller stopped trying. Generac lists these causes:

• Fuel shutoff valve closed
• Not enough fuel pressure, often from a low LP tank
• Wrong fuel type (NG or LP) selected in the controller
• Air filter problems, including ice in freezing weather
• Low battery or installation issues

Start with the fuel valve and fuel setting. See the full Generac error code 1100 guide for each step.

1500 to 1522: RPM sensor loss (including 1501 and 1505)

RPM sensor loss means the controller is not getting a valid engine speed signal. Generac says the owner checks are the same for every code in this range, including 1501, 1505, 1511 and 1515. It can happen during a start attempt or while the engine is running.

• If it fails during a start: A weak battery or loose, corroded battery cables are the most likely cause. Generac also lists a closed fuel valve, the wrong fuel setting and an LP tank under about 30 percent.
• If it shuts down while running: A battery problem is less likely. Look for an overload or a big load starting suddenly, such as several large appliances at once.

Generac says batteries typically last 3 to 5 years. Our guides on Generac error code 1501 and Generac error code 1505 troubleshooting walk through each check.

What do Generac engine protection codes mean?

Engine protection codes shut the generator down to prevent engine damage. They cover oil pressure, temperature and engine speed. Some have simple owner fixes, and others need a dealer.

1300: Low oil pressure

The low oil pressure sensor stops the engine when oil pressure is not adequate. Generac says the usual cause is a low oil level from oil use, a leak or missed maintenance.

1. Let the engine cool and check the dipstick.
2. Top off with the oil your owner’s manual lists. Do not overfill.
3. Clear the alarm and restart.

If the oil level is correct and the alarm returns, call a dealer. The Generac 1300 low oil pressure guide has more detail.

1400 and 1401: High temperature

High temperature means the engine overheated. Generac points to blocked intake or exhaust airflow, or low fuel pressure.

• Clear leaves, snow, plants and debris from the intake, exhaust and back of the unit.
• Keep a clear area of about 3 feet around the generator, as Generac advises.
• Make sure nobody has built an enclosure around the unit.
• Let it cool fully, then clear the alarm and start it manually.

1600 to 1603: Underspeed

Underspeed means engine speed dropped below the required level. Generac says the unit is usually overloaded or has a fuel supply issue. Large appliances can draw 3 to 4 times their running wattage when they start.

Generac’s suggested checks are:

• Run the generator with no loads. If it runs normally, the problem is likely overload.
• Make sure the fuel valve is fully open and the fuel setting matches your fuel.
• Check the LP tank level or ask your gas utility about an outage.
• Inspect and defrost the air filter, and clear snow or debris.

Read the full Generac error code 1600 guide for staggered load testing.

1200 to 1208: Overspeed

Overspeed means the engine ran faster than it should. Generac lists this code among those that need an authorized dealer. Clear the alarm once; if it returns, leave the code on the screen and call for service.

What do Generac electrical output codes mean?

Electrical output codes mean the generator is not making the right voltage or is being asked for too much power. Undervoltage and overload are the two you will see most. Overvoltage and wiring errors need a dealer.

1900 to 1907: Undervoltage (including 1902)

Undervoltage means the generator is not producing proper voltage, either over a long period or after a sudden drop. Generac lists these causes:

• Fuel setting that does not match the actual fuel
• Low fuel supply, including an LP tank below 30 percent
• Wrong fuel jet position on Guardian models, mostly after a new install
• Ice in the air filter or snow blocking airflow
• Circuit, firmware or voltage production problems

Generac specifically notes that heavy load during extreme weather can cause error 1902. See our Generac 1902 undervoltage guide for the full checklist.

2100 to 2103: Overload, remove load

Overload means your home is asking for more power than the generator can supply. Generac lists these common causes: a newly added large appliance, a faulty load manager, several big loads starting at once, or an undersized generator.

1. Turn off non-essential circuits at the breaker panel.
2. Check that any Generac load managers have the right lockout settings.
3. Clear the alarm and restart with loads off.
4. Add circuits back one at a time.

If removing load does not fix it, Generac says a service call is needed.

1800 and 1801: Overvoltage, and 2098 or 2099: Wiring error

Overvoltage means output voltage went too high. Wiring error means the sensing wires to the transfer switch may be wired wrong. Both are on Generac’s dealer-required list, so do not open the transfer switch to look for the problem.

What do Generac battery and charger codes mean?

Battery and charger codes mean the starting battery is weak or is not being charged correctly. A weak battery is also a top cause of start failures and RPM sensor alarms. These are some of the easiest Generac error codes to fix yourself.

2750, 2751 and 2760: Low battery, very low battery, battery problem

Low battery means the battery needs charging. Generac’s steps are:

1. Compare the battery voltage with the DC voltage shown on the controller.
2. If the battery reads under 12.5 volts DC, give it 24 hours to charge.
3. If that does not fix it, replace the battery.

Clean and tighten corroded or loose terminals at the same time.

2770: Charger warning

Charger warning means the battery is not charging properly. Generac says it triggers when battery voltage stays under 12.5 volts at the end of an 18-hour charge cycle. It can also point to a blown T1 fuse or a charging circuit problem. A worn-out battery is the easy fix; fuse and circuit work belongs to a dealer.

2780: Charger missing AC

Charger missing AC means the battery charger is not getting its 120-volt supply. Generac says this happens when the T1 circuit is not connected or its fuse is blown. That circuit runs through the transfer switch, so call a dealer.

What do Generac shutdown and maintenance codes mean?

These codes usually mean a switch is off or a service interval has arrived, not that something is broken. They are often the quickest Generac error codes to clear. Always find out why a switch was turned off before you turn it back on.

2800 and 2801: Auxiliary shutdown

Code 2800 means an emergency stop or auxiliary shutdown switch is open, so the generator will not run. Code 2801 usually points to a secondary shutdown switch. Generac says the switch is often left off after service or bumped by accident.

• Guardian (Evolution): Look for an external switch on the back of the generator. Some two-cylinder models also have one inside near the control panel. Press the “I” side for ON.
• Next Generation (Power Zone 200): Check the factory switch and any secondary switch that may be mounted near the transfer switch.

Generac warns that some service providers turn these switches off on purpose while a unit waits for repair. Check with your dealer first. Full steps are in our Generac error code 2800 guide.

Yellow maintenance reminders

“Schedule A,” “Schedule B” and “Schedule C” maintenance reminders mean a service interval has been reached. “Inspect Battery” asks you to check the battery and terminals. Do the service listed in your owner’s manual, then dismiss the reminder.

3217: Low fuel pressure

Generac lists 3217 as an engine low fuel pressure warning. Check that the fuel valve is open and that your LP tank is not low. Fuel pressure testing needs a manometer and should be done by a pro.

How do you reset a Generac generator?

To reset a Generac generator after an alarm, clear the code at the controller, fix the cause, then start it with the house loads off. On an Evolution controller, Generac’s steps are OFF, then ENTER twice, then AUTO. On a Power Zone 200 controller, hold OFF for about 3 seconds, then press AUTO.

Generac warns that starting a generator with all loads applied can damage it. Use this sequence from Generac’s support site when an alarm happens during an outage.

When should you do a hard reset?

A hard reset removes all power from the controller. Generac says error codes usually do not need a hard reset to clear, but it may help with temporary controller glitches. The steps involve pulling the 7.5-amp controller fuse, disconnecting the battery (black negative first), switching off the service disconnect, then reconnecting in reverse (red positive first). Generac notes this may cut power to your whole home and says to call a technician if you are not comfortable doing it.

Is it safe to work on a Generac generator yourself?

You can safely do the outside checks, such as the fuel valve, oil, battery terminals, air filter and shutdown switches. Anything inside the transfer switch, controller or fuel system is a job for a licensed pro. A standby generator can start on its own at any time when it is in AUTO.

When should you call a pro?

Call a Generac authorized service dealer when a red alarm comes back after one clear and restart, or when the fix involves fuel pressure, wiring or the transfer switch. Generac notes that only an authorized dealer can do warranty repairs. You can reach Generac customer support at 1-888-436-3722 to find one.

Call a dealer if:

• The same alarm returns after you clear it once
• You see overspeed (1200s), overvoltage (1800s), wiring error (2098, 2099) or controller fault (1000s) codes
• You see 2780 (charger missing AC) or a charger fuse problem
• The oil level is correct but 1300 keeps coming back
• You suspect low fuel pressure or the unit was installed in the last year
• The generator runs but your home does not switch over to generator power
• You smell gas or exhaust, or see fuel or oil leaking

How can you prevent Generac error codes?

Most Generac error codes are prevented by steady maintenance, a healthy battery and a clear area around the unit. Small checks between outages catch problems before a storm.

• Follow the A, B and C maintenance schedules in your owner’s manual.
• Replace the battery every few years. Generac says batteries typically last 3 to 5 years.
• Keep a 3-foot clear zone around the generator, and clear snow from the intake and exhaust in winter.
• Keep your LP tank above about 30 percent.
• Use a load manager so large appliances do not start at the same time.
• Glance at the status light each week to make sure it is green and in AUTO.

Frequently asked questions

Related Generac error code guides

• Generac error code 1100: overcrank fixes
• Generac error code 1300: low oil pressure
• Generac error code 1501: RPM sensor loss
• Generac error code 1505 fixes
• Generac error code 1600: underspeed
• Generac error code 1902: undervoltage
• Generac error code 2800: auxiliary shutdown
• All generator error code guides