Top 7 Generac Generator Error Codes and What They Mean

If you own a Generac home standby generator, you may eventually see a fault code on the controller screen—often accompanied by a red light. These codes are designed to help identify system issues quickly and protect your generator from damage. At Best Care Home Services, we specialize in diagnosing and repairing Generac generator issues across the Memphis area. Below, 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. Some faults can be cleared by the homeowner, while others require certified service. In most cases, the generator will not run while the error code is active.

Top Generac Generator Error Codes and What They Mean

Error Code 1505 – RPM Loss During Start

This code means the generator tried to crank, but the controller didn’t detect the engine reaching operating speed. It typically points to a weak battery, failed starter relay, or 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, call for service.

Error Code 2800 – Auxiliary Shutdown

This 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.

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.

Error Code 1902 – Low Oil Pressure

This is 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, failed voltage regulator, or internal alternator problems.

What to do
Disconnect high-wattage appliances and restart the generator. If the problem continues, professional testing is required.

Error Code 1100 – Overvoltage

This occurs when the generator output exceeds safe limits. It may be caused by a faulty voltage regulator, incorrect wiring, or an internal control issue.

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

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, make sure the tank isn’t empty. If it 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
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.

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
• 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 and ensure your system is ready for any power outage.

Preventing Future Error Codes

Regular maintenance is the best way to reduce fault codes and keep your generator running smoothly. Here’s what we recommend:

• 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

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 at 901-624-1401 to schedule expert diagnostics and fast repairs. We’ll get your home backup power running safely and reliably.