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How to Solve Generac Generator Fault Codes [Quick & Easy]

Are you the owner of a Standby generator user who is always fighting with the Generac generator fault codes? If you are facing errors like 1200+,1300+,1400+, etc. you may wonder how to find the reason and fix it.

These are frustrating codes, especially when you relying just on your generator. You don’t need to worry about we will discuss most of them in this article and help you to resolve the error codes by yourself.

Is it necessary to know the Generac Generator fault codes?

If you are a Generac standby generator user it is essential for you to learn the basic information about the error codes of your generator. In an emergency situation, you may be unable to find a generator mechanic to clear the error code and start the generator for you. There are multiple error codes that you can fix yourself. Instead of staying in the dark, you need to learn the basic error codes and try to fix them yourself.

How to Find Generac Generator Fault Codes

Finding the error code in Generac Generators is very easy. If your Generac generator shows a red light it means that your generator has some kind of fault. You need to uncover the top of your generator and check the display to identify the error code.

Warning: won’t try to do anything in your generator if it is under warranty, contact an authorized dealer for repair.

Note: Before discussing error codes I want to suggest resetting your Generac generator, and try to start in manual and then try in auto mode. In most common error situations, it solves the problem.

To do that press [off] on the control panel, Press [Auto], and then Press the Manual button to start [Manual].

How to Start Generac Generator Manual

Error Code 1100 and 1101 [Generator Overcrank]

The error code 1100 shows that your generator is not getting the required RPMS or there is no fuel supply to the generator.  The error code 1101 is shown only in 8kW and 9 kW generators.


  1. To solve 1100’s error code you have to reset your Generac generator and then switch to auto.
  2. If still exists check the fuel supply connection of your Generac generator.
  3. Check the battery connection and ground connection.
  4. If you try all the above three steps and still not working try to contact a professional expert.

Error Code 1200, 1205 and 1207 [Generator Overspeed]

Generac generators usually display these codes. In this case, your generator starts a few seconds or minutes and then shuts off, it happens when the controller of your generator detects high Revolutions Per Minute (RPM).

According to Generac’s official Website (https://www.generac.com/), the main cause of this problem is defective ignition coils, and you can’t fix it yourself. You must contact an expert mechanic to check the problem and fix it.

We also recommend that you should call a mechanic for this problem.

Error Code 1300 [Low Oil Pressure]

This is a common error code, especially in 10KW Generac generators. This happens due to the supply of low oil pressure to the engine than required. There are multiple easy-to-fix reasons for this issue. Let’s try them step by step.


  1. Check the oil level of your generator, if it is lower than the required level try to refill it with the recommended engine oil.
  2. You also need to check for loose or faulty [Pressure Switch] if it is connected loose try to fix it or replace it if faulty.
  3. This can be also caused by an outdated Firmware version of your Generac generator, check for the latest version and update it if required.
  4. If the above problems are not found in your generator, this indicates that your generator’s fuel pump is faulty, for this problem, you need to call a mechanic.

Note: If you try any above solutions, you must restart your generator in [Manual Mode]

Error Code 1400 [High Temperature]

This problem occurs when the control panel detects that your generator is too hot. This is possible when the airflow of the generator is blocked. Wiring and “Temp Switch” can also be the cause of this problem.


  1. Check the air filter and vent for blockage, clear the blockage and you are good to go.
  2. Check the wiring of your Generac generator for loose or faulty connections.
  3. You must check the temp switch if the above solution doesn’t work for you.

Note: if the problem still exists you need to contact the professional generator mechanic.

Error Code 1500, 1501, 1505, 1511, 1515 [RPM Sense Loss]

These errors occur when the controller of the Generac generator does not sense the RPM of the engine. In simple the controller is unable to know whether the engine is running or cranking.

In this case, your generator will be unable to perform weekly tests or manual start. Instead of starting it will sound buzz in the control panel. This problem can occur for multiple reasons some of which are listed below.

  1. First, you need to Reset the generator, start it manually, and then switch to Auto Mod.
  2. Your fuel supply is disconnected and blocked. Check the fuel supply and try to start it in [Manual Mod].
  3. A faulty or low battery can also cause this error. Try to check your battery and recharge/replace it if required.
  4. Magnetic Pickup Unit (MPU) is also a cause of this error code “RPM Sense Loss” You need to replace the MPU cable.
  5. You need to check the spark plug and replace it if you find it faulty.

Note: If your generator still shows “RPM Sense Loss” try to call an authorized expert mechanic.

Error Code 1600 and 1603 [Low Speed/ Underspeed]

The “Underspeed” error code indicates that the controller of your Generac generator is not detecting the correct RPM of the engine. If the generator runs 5-10 Hz lower than the generator required Hz it shows the underspeed error code.

This problem can happen due to Overload, Fuel-related issues, a bad Stepper, or a faulty regulator.


  1. If your generator is overloaded, reduce the load, and the problem is solved.
  2. Check your spark plug if it is connected properly and in the best condition if not cleaning and replacement are recommended.
  3. Check the fuel supply and condition of fuel, sometime supply of less fuel can also cause this when the engine requires more fuel.
  4. The Stepper can also cause an Underspeed error, you need to check the stepper carefully and replace it if required.
How to Change Stepper in Generac Generator.

 If the problems are not found in your generator, you need to check the regulator’s fault. This regulator’s fault can be only fixed by an expert.

Note: If you aren’t familiar with the generator repair you need to call an expert for repair.

Error Code 1900, 1901, 1902, and 1906 [Low Voltage output/ Undervoltage]

The error code shows that the output power of your Generac generator is lower than 80% of your generator-rated voltage. There are multiple reasons that may accrue, let’s discuss them one by one.


  1. First, you need to check the current firmware of your generator, if it is not up to date try to update it with the latest Firmware of your generator model.
  2. Faulty and loose electric wiring connection is another cause of this Undervoltage error, you need to check the wiring of your generator and tight it where it senses loose or replace it if found faulty.
  3. Control Panel: disconnect the battery and T1 cable from the controller, wait a few minutes (about 5), and reconnect the battery and control panel try starting it manually and then switching to auto mode.
  4. A faulty Starter motor is another cause of this error code; in this case, you need an expert to replace a starter motor for you.
  5. The Brush of your generator’s electrical motor can also cause this problem, you need an expert generator mechanic to repair and replace this for you.

Error Code 2100, 2102, and 2103 [Generator Overload]

This error code shows that your generator is overloaded, you can just remove the extra load from your generator and restart it, and it works fine in most cases.

If it still not working, you need to check the fuel supply of your generator, sometimes a low fuel supply can also cause this problem.

Check the stepper motor, a faulty stepper can be also a reason for this error code.

Error Code 2299 [Generator Undervoltage]

This error code is also part of Overloading; in this case, your generator may be connected to a high load while it tries to start. First, you need to remove the load from your generator or simply switch off the main load breaker and restart your generator.

Low Battery

The battery error is a simple error that occurs when your generator’s battery is low or faulty, so to solve this error you need to check the connection of your battery cables and check the battery charge.

If you find a loose connection try to tighten it and if it is low in charge try to charge it. You may also replace the battery if it is faulty. Keep in mind you must use only the battery which is recommended in your manual.


Above listed are some common error codes that are commonly shown in Generac generators. Some of them can be fixed with a little knowledge of electricity and some needs expert to fix. We once again recommend that if your generator is in full warranty or parts warranty, You must not attempt to repair it. The best way to make your generator run is to call the authorized mechanic from the Generac dealer.

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