What Generac Generator Error Codes Mean And How to Fix Them

Generac error codes mean your generator may not be available when you need it most. When they appear on your controller screen, usually accompanied by a red light, it means the controller that monitors engine vitals has triggered a shutdown to prevent damage.

At Best Care Home Services, we specialize in diagnosing and repairing Generac generator issues across the Memphis area. In this blog, we’ve broken down the most common Generac generator error codes, what they mean, and when you should call in a pro.

Understanding Generac Fault Codes

Generac Generator Error Codes are typically numeric (such as 1505, 2800, or 1902) and appear on the control panel. There are two types of codes: warning codes, which alert you but keep the unit running, and shutdown codes, which stop the unit entirely. The generator will not run while a shutdown error code is active.

Some faults can be cleared by the homeowner, while others require certified service. Our team includes factory-trained Generac professionals, who can inspect, repair, and maintain Generac generators. But before you call in the pros, here’s what you, as a homeowner, need to know.

Generac Generator Error Codes: What Each One Means

CODE	FAULT NAME	MOST COMMON CAUSE	TYPE	DIY OR CALL A PRO?
1505	RPM loss during start	Weak battery, failed starter relay, faulty RPM sensor	Shutdown	Try DIY first
2800	Auxiliary shutdown	E-stop switch left off after maintenance	Shutdown	Try DIY first
1902	Low oil pressure	Low oil level or failed oil pressure sensor	Shutdown	Check oil first
1200	Undervoltage	Heavy load at startup, failed voltage regulator	Shutdown	Try DIY first
1100	Overvoltage	Failing automatic voltage regulator (AVR)	Shutdown	Call a pro
1603	Engine failed to start	Fuel supply issue, spark plug wear, dead battery	Shutdown	Try DIY first
1300	Low battery	Dead battery or failed trickle charger	Warning	DIY-friendly

Error Code 1505 – RPM Loss During Start

Generac error code 1505 means the generator tried to crank, but the controller didn’t detect the engine reaching operating speed. It typically points to a weak battery, a failed starter relay, or a faulty RPM sensor.

What to do:
Check and load-test the battery. Inspect the starter relay and wiring. Try to manually start the generator. If the code reappears after attempting these steps, it’s not a DIY fix. It’s time to call for service.

Error Code 2800 – Auxiliary Shutdown

The Generac 2800 code indicates that one of the generator’s emergency stop switches has been triggered or a safety shutdown circuit is open. This is common after recent maintenance, because a technician may have left an E-stop switch in the off position.

What to do:
Locate the two E-stop switches and ensure both are in the ON position. Check the wiring around the shutdown switch. Reset the controller and try restarting. If the 2800 code doesn’t clear after checking the switches, it may need a dealer-level reset.

Error Code 1902 – Low Oil Pressure

Code 1902 indicates a critical shutdown. It occurs when the generator detects that oil pressure has dropped below a safe threshold during operation or startup.

What to do:
Check oil levels and add oil if low. If the level is correct, the oil pressure sensor may be faulty and require replacement. Do not keep trying to run the unit with this error.

Error Code 1200 – Undervoltage

The controller has detected that the generator is producing voltage below the acceptable range. This can result from overload, a failed voltage regulator, or internal alternator problems. Heavy load demand at startup (such as with large HVAC systems or well pumps) is a common culprit that homeowners often overlook.

What to do:
Disconnect high-wattage appliances and restart the generator. If the problem continues, the voltage regulator is likely the failure point, and professional testing is required.

Error Code 1100 – Overvoltage

The Generac generator error code 1100 occurs when the generator output exceeds safe limits. It may be caused by a faulty automatic voltage regulator, incorrect wiring, or an internal control issue — all of which require a professional to repair.

What to do:
Shut the unit down and contact a certified technician. Overvoltage can damage sensitive electronics and appliances connected to the generator.

Error Code 1603 – Engine Failed to Start

After multiple crank cycles, the engine didn’t start. This fault may result from fuel supply problems, spark failure, or sensor malfunctions.

What to do:
Check the gas line, fuel valve, and battery. If your generator is on propane, check that the tank isn’t empty. Natural gas generators, though, rarely have a fuel supply issue unless there’s a shutoff valve problem. If the fuel level is fine, check the spark plugs. Spark plugs are often overlooked, but they can wear out over time. If your generator still won’t start, call for professional service.

Error Code 1300 – Low Battery

The controller has detected a battery voltage below the recommended level. This may prevent the generator from starting automatically during an outage.

What to do:
The generator’s built-in trickle charger can fail, causing repeat 1300 codes even after you’ve installed a new battery. Check the battery voltage with a multimeter. Clean terminals, tighten connections, or replace the battery if needed. This is one of the easiest faults to resolve.

How to Reset a Generac Generator After a Fault Code

Clearing a fault code and resetting the controller are two separate steps. Before you reset, perform the maintenance steps we outlined for each code above. Then, reset the generator to determine whether further repair is needed.

To perform a basic reset: Navigate to the fault on the control panel, press Enter to acknowledge, then use the controller menu to reset. If the fault condition is gone, the generator should return to auto mode. If the code reappears, though, the underlying issue hasn’t been fixed, and resetting it won’t work.

Certain codes can’t be reset by the homeowner because they require a dealer-level login to clear. In that case, you’ll need to call a technician to return the generator to service.

When to Call Best Care Home Services

While some basic Generac generator errors can be reset at home, many fault codes signal deeper issues that require diagnostics and repair. At Best Care Home Services, our factory-certified technicians can:

• Read and interpret all Generac fault codes
• Clear dealer-level fault codes
• Repair or replace failed sensors, relays, and batteries
• Diagnose fuel, electrical, or mechanical faults
• Perform full safety testing after clearing the fault
• Provide regular maintenance through our ComfortGuard Plan

We service Generac generators throughout Memphis to ensure your system is ready for any power outage. Call us to schedule your Generator service!

Preventing Future Error Codes

Regular maintenance is the best way to avoid fault codes and keep your generator running smoothly. Most maintenance issues show up on the generator control panel before they become a real failure, so it’s crucial to stay on top of them.

We recommend performing these preventative maintenance tasks:

• Run your generator under load once a month
• Keep oil levels topped off and filters clean
• Replace the battery every 2 to 3 years
• Have a certified technician inspect your system annually
• Enroll in a maintenance plan to catch issues early

Frequently Asked Questions

What does a red light on a Generac generator mean?

The red light on the Generac generator’s control panel means the system has entered fault mode, meaning it won’t run until it’s fixed. It’s the most serious of the generator’s status indicators. Common causes include improper oil levels, overheating, electrical issues, and failed sensors.

Can I reset a Generac error code myself?

Yes, some codes can be reset without a trained technician, but if they persist after you’ve tried troubleshooting, it’s time to call a professional. Some codes, like 1100, can’t be solved without a certified technician.

What causes a Generac generator to shut down?

Generators usually shut down to protect their engine and electrical components. The causes include low oil levels, electrical overloads, fuel supply issues, and sensor malfunctions.

Generac Generator Showing an Error Code?

Don’t ignore it. If your Generac generator is flashing a code or won’t start, call Best Care Home Services to schedule expert diagnostics and fast repairs. We’ll get your home backup power running safely and reliably.