Generac Error Codes: Meanings, Common Alarms & What to Do

Common Generac Error Codes at a Glance

This is not a complete universal code table.

Generac alarm descriptions differ by controller generation, so the exact displayed text matters.

What Is a Generac Error Code?

Generac uses several terms for controller messages, including:

• Error code
• Alarm code
• Fault code
• Fault alarm
• Warning
• Maintenance reminder

These do not all mean the same thing.

Alarm

An alarm can stop the generator or prevent automatic operation.

Warning

A warning alerts you to a condition that requires attention but may not immediately shut the generator down.

Maintenance Reminder

A maintenance reminder tells you scheduled service is due.

Do not treat a maintenance reminder like an engine-protection alarm.

Why Is My Generac Showing a Red Light?

A red status light generally indicates an active alarm or shutdown condition.

During an outage, if a Generac was running and then stops because of an alarm, the red status indicator will illuminate and the controller or Mobile Link can display the fault.

The correct sequence is:

1. Read the controller.
2. Write down the code.
3. Identify the cause.
4. Correct the cause where appropriate.
5. Clear the alarm.
6. Return the generator to AUTO.
7. If the alarm returns, call a service dealer.

Do not skip straight to step 5.

Generac Code 1100 / 1101: Overcrank

An overcrank alarm means the controller attempted to start the engine but the engine did not establish normal operation within the permitted starting attempts.

Common areas to check include:

• Fuel availability
• Fuel shutoff valve
• Natural-gas or propane supply
• Spark plugs
• Fuel-system condition

If the engine cranks normally but never fires, this is different from a dead-battery no-crank condition.

Read the Generac won't-start guide →

What to Check for Overcrank

Start with the simple external checks:

Fuel Supply

For natural gas:

• Confirm service is available
• Check whether other gas appliances are working
• Confirm the generator fuel valve is open

For propane:

• Check tank level
• Confirm supply valve is open

Spark Plugs

Worn or fouled plugs can contribute to a crank/no-start condition.

Read the Generac spark plug guide →

Fuel-System Setup

A newly installed unit that repeatedly overcranks may have:

• Fuel pressure issue
• Incorrect fuel configuration
• Installation issue

That belongs back with the installer or an authorized service dealer.

Generac Code 1300: Low Oil Pressure

Code 1300 means LOW OIL PRESSURE.

The first thing Generac tells owners to check is the engine oil level.

What to Do

1. Safely shut the generator down.
2. Allow oil to settle.
3. Check the dipstick.
4. Add the correct oil if needed.
5. Do not overfill.
6. Inspect for obvious oil leakage.

If the oil level is correct but Code 1300 remains or returns:

contact a Generac service dealer.

Read the Generac oil-change guide →

Generac Code 1400 / 1401: High Temperature

High-temperature alarms indicate the generator has detected excessive operating temperature.

Basic external checks include:

• Blocked intake area
• Leaves or debris around enclosure
• Vegetation restricting airflow
• Heavy continuous operation

Let the generator cool before inspection.

Do not remove safety panels and operate the generator in an unsafe configuration.

If the alarm returns after obvious airflow problems are corrected, use a service dealer.

Generac 1500-Series Codes: RPM Sense Loss and Speed Faults

Generac uses 1500-series codes for certain RPM and speed-related faults.

These can involve:

• Engine speed signal
• Engine stall
• Fuel interruption
• Ignition issue
• Sensor problem
• Controller issue

The exact 1500-series number matters.

Do not reduce every 1500-series alarm to one generic diagnosis.

Record the complete code displayed on the controller.

If the fault immediately returns after reset, professional diagnosis is the sensible next step.

Generac Code 2400: Fuse Problem

Code 2400 means the 7.5 amp controller fuse is missing, improperly seated or blown.

Generac's current guidance applies this code to current next-generation and recent Guardian air-cooled standby systems.

What to Check

With the generator safely disabled:

1. Locate the 7.5A controller fuse.
2. Confirm it is installed correctly.
3. Check whether it has blown.
4. Check battery condition.
5. Check battery cables and connections.

If the fuse is blown, it can be replaced with the correct 7.5A fuse.

But if it blows again:

stop replacing fuses and call a service dealer.

A repeatedly blown fuse points to an unresolved electrical or starter-circuit problem.

Generac Battery and Charger Warnings

Battery-related warnings can appear when:

• Battery voltage is low
• Battery condition is poor
• Charging system is not operating correctly
• Installation wiring is incomplete or incorrect

A weak battery can create:

• No-crank condition
• Slow cranking
• Failed startup

But if a brand-new battery repeatedly goes flat, investigate the charger circuit rather than buying another battery.

Read the Generac battery guide →

Generac Overspeed Alarm

An overspeed alarm means the controller detected engine speed above its permitted operating range.

This can involve:

• Engine-speed control
• Governor system
• Speed sensing
• Controller fault

This is not a fault I would repeatedly reset and ignore.

If the alarm returns, use an authorized service dealer.

Generac Underspeed Alarm

An underspeed condition means engine speed fell below the expected operating range.

Possible contributors include:

• Fuel delivery
• Excessive electrical load
• Engine problem
• Speed-sensing fault

If the generator runs unloaded but shuts down after the house transfers onto it, both:

load + fuel supply

deserve attention.

Read Generac starts then shuts off →

Generac Overload Alarm

An overload means the generator is being asked to provide more electrical power than the system can safely support.

Potential causes include:

• Too many heavy loads
• Multiple HVAC compressors
• Electric heating
• Well pumps
• Pool equipment
• Electric water heater
• Undersized generator

Do not restart with the exact same heavy loads still applied.

Remove loads, restart safely and restore circuits gradually.

Calculate your generator size →

Why the Exact Generac Controller Matters

Generac has used multiple home standby controller generations.

Common examples include:

• Nexus
• Evolution 1
• Evolution 2
• Sync
• Power Zone 200
• Power Zone 410 on selected liquid-cooled systems

The method used to clear an alarm can differ.

Current Power Zone 200

On current next-generation air-cooled units, Generac's current procedure is generally:

1. Hold OFF for at least 3 seconds.
2. Confirm the alarm clears.
3. Press AUTO to return the unit to service.

If the alarm immediately returns:

contact a Generac authorized service dealer.

Evolution / Sync Controllers

The clearing procedure differs from Power Zone 200 and should be followed using the correct Generac instructions for that controller.

Nexus Controllers

Nexus controllers use their own clearing procedure.

Do not use a Power Zone reset sequence on a Nexus generator simply because both are Generac.

How to Clear a Generac Error Code

Only clear the alarm after the underlying cause has been addressed.

For current Power Zone 200 controllers:

1. Hold the OFF button for at least 3 seconds.
2. The alarm should clear.
3. Press AUTO.
4. Verify the generator returns to ready status.

Generac specifically says that if the alarm returns after AUTO is selected, contact an authorized service dealer.

That is the kill rule.

Should You Hard Reset a Generac?

Usually not as the first move.

Generac says error codes generally do not require a hard reset simply to clear them.

A hard reset removes power from the controller and is used for certain persistent control-panel problems.

Do not use a hard reset as a substitute for diagnosing:

• Low oil pressure
• Overcrank
• High temperature
• Fuse problems
• Engine-protection faults

Fix the cause first.

How to Restart a Generac After an Error During an Outage

If the generator faulted while it was actively powering the home, the restart process needs additional care.

Generac's current guidance includes:

1. Turn the generator OFF.
2. Turn the generator disconnect / main line circuit breaker OFF.
3. Remove household loads at the electrical panel.
4. Clear the alarm after correcting its cause.
5. Return the generator to AUTO.
6. Confirm it starts successfully.
7. Turn the generator disconnect back ON.
8. Restore household circuits one at a time.

Starting the generator with the full household load still applied can damage the system.

If you are not comfortable safely controlling the generator disconnect and household breakers, call a qualified technician.

Generac Error Code Comes Back After Reset

This is important.

If you:

• Correct the obvious condition
• Clear the alarm
• Return the generator to AUTO

and the same alarm immediately returns:

stop resetting it.

Generac's current support guidance says to contact an authorized service dealer.

Repeated resets can:

• Hide useful fault history
• Delay proper diagnosis
• Potentially risk equipment damage

The code is there for a reason.

Error Code vs Hours of Protection

Some owners mistake the controller's hours of protection reading for an alarm code.

A value followed by:

(H)

may represent generator hours/protection history rather than an error code.

Read the complete display before assuming a large number is a fault.

Error Code Shows in Mobile Link

Compatible Generac systems can send alerts to Mobile Link.

Mobile Link can be useful for:

• Recording the exact alert
• Seeing generator status remotely
• Reviewing event timing

But Generac's current guidance notes that premium Mobile Link users can dismiss some maintenance reminders, while warnings and alarms still need to be handled through the generator/control process.

Do not assume clearing something in an app repairs the generator.

Red, Yellow and Green Generac Lights

Generac status lights provide a quick indication of system state.

Green

Generally indicates ready/normal automatic standby condition.

Yellow

Generally indicates a warning or maintenance condition that needs attention.

Red

Generally indicates an alarm or shutdown requiring diagnosis.

Read the controller message for the actual reason.

The light color tells you the category.

The code tells you the problem.

What Error Codes Can You Fix Yourself?

Some simple problems may be owner-checkable.

Examples include:

• Low oil level
• Blown/missing controller fuse
• Discharged battery
• Closed fuel valve
• Generator accidentally left in OFF

But even these have limits.

If:

• Fuse keeps blowing
• Low oil alarm returns with correct oil level
• Battery repeatedly dies
• Alarm immediately returns
• Fuel pressure needs adjustment

move to professional diagnosis.

What Codes Need a Generac Dealer?

Use a service dealer when:

• Alarm immediately returns
• Overspeed/underspeed persists
• RPM-sense fault persists
• Low oil pressure remains with correct oil level
• High-temperature fault returns
• Fuse keeps blowing
• Controller/electrical fault is suspected
• Fuel-system pressure needs diagnosis
• You are not comfortable safely isolating the generator

Find Generac service dealers →

What to Tell the Generac Service Dealer

Before calling, collect:

• Exact error code
• Exact message
• Generator model
• Serial number
• Operating hours
• Whether outage was active
• How long generator ran before fault
• Recent maintenance
• Fuel type
• What you already checked

This can reduce diagnostic time and stops the call beginning with:

"It just doesn't work."

Preventing Generac Error Codes

Not every alarm is preventable, but basic maintenance reduces avoidable faults.

Before severe-weather season:

• Check oil
• Check battery condition
• Confirm fuel supply
• Review scheduled maintenance
• Keep enclosure airflow clear
• Confirm generator is in AUTO
• Make sure exercise cycles complete normally

Read the Generac maintenance guide →