Generac Generator Weekly Test Not Working (Why It Fails & How To Troubleshoot)

Every Generac home backup generator is programmed to run a diagnostic test. It can be weekly, bi-weekly or monthly to ensure the unit works. Thanks to their patented Quiet-Test technology that allows users to pre-set and run self-diagnostic tests on home backup generators.

But why does the Generac generator weekly test fail to run? What can you do to fix the issue?

The generator might fail to do weekly exercises for multiple reasons. These include, low battery voltage, contaminated fuel or fuel supply issues, clogged air filter, faulty spark plug, dirty fuel filter, faulty control board and sensor. These issues can be resolved by resetting the generator or troubleshooting the parameters one by one.

If you own a Generac generator, this guide will help you rectify the issues step by step. Here we’ve covered everything related to the Generac generator weekly test and how to troubleshoot the critical issues.

Let’s begin!

Why Your Generac Generator Weekly Test Is Not Working?

The generator might fail to do weekly exercises for the following reasons:

If your Generac generator is not running its weekly test, the issue is usually linked to low battery voltage, fuel problems, or a faulty control board. Regular maintenance helps prevent these errors before they stop the test from running altogether.

Low Battery Voltage (weekly test not running)

One common reason your generator might skip its weekly test is simply an aging battery. Open the lid and check the display on the control panel — if it’s a voltage issue, the screen will usually prompt you to inspect the battery. Check the voltage, verify if the connections are tight, clean off any corrosion on the terminals, and try running the test manually.

To keep this from happening again, many Generac owners use a small trickle charger. A simple option is the Generac OEM charger cord, which keeps the battery topped up automatically.

Sometimes the Generac weekly exercise not working issue appears even when the generator starts fine. In many cases, the control board or the exercise timer setting becomes corrupted, and resetting the system usually fixes it quickly.

If your generator still fails the test even after checking the battery and charger cord, it might be related to a missing or faulty AC charger, which can stop the battery from charging properly.

If you own a Guardian standby unit and your battery is more than three years old or no longer holds a charge, replacing it is often the easiest fix. A reliable choice is the 12V 26R Generac-compatible battery, which gives your generator enough power to run its weekly test without issues.

To help you choose the right replacement, here’s the official Generac battery compatibility chart.

Fuel Supply Issues (weekly exercise not working)

All home backup Generac generators run on natural gas or liquid propane (LP) fuel. If the fuel is contaminated or the fuel supply is restricted, the unit may not run the weekly test and not start. 

That said, the generator will display error code 1100 if it’s low on gas. In that case, you must ensure that the gas is turned on. If the unit doesn’t perform the weekly test even though you’ve turned on the gas, you must contact an authorized service dealer.

Engine / Spark Problems (self-test not working)

An overheated or overloaded engine can prevent the generator from running the weekly test. It can be due to problems related to engine components or the spark plug. We’ve given step-by-step instructions on troubleshooting these critical issues in the next segment.

Control Board or Schedule Fault (exercise timer)

The generator’s control board may be damaged, preventing it from running the weekly test. For example, 7.5 AMP is fused to the control module of the Propane 20KW Guardian series Generac generator, and you might notice the LCD screen will not display anything. In that case, the generator will not run the test automatically or manually, and you’ll need to install a new control module.

Sensor Faults (oil pressure, RPM sense)

Malfunctioning or faulty sensors can falsely trigger several conditions, such as high engine temperature or low oil pressure. This, in turn, can prevent the engine from running the weekly test.

Generac Generator Weekly Test Not Working: Quick Fixes

Your Generac generator might not run the weekly test cycle even after pre-programming it and running the test manually. In that case, consider resetting and restarting the generator.

Reset the generator:

Step 1: Open the lid.

Step 2: Turn off the electricity/shut down the power of the unit by switching the circuit breaker switch to OFF.

Step 3: Press the red OFF button on the control panel.

Step 4: Press the Enter key.

Step 5: Wait 30 seconds.

Step 6: Press the blue Manual button on the control panel once. This will let the generator start running the test for 5 minutes.

Step 7: Allow it to run the test, and if it doesn’t, put it into the OFF position by pressing the red button.

Step 8: Wait 30 seconds or more until the system cools down completely. 

Step 9: Press the Auto button on the controller

Now you have reset the generator, and it will make three attempts to start. If it doesn’t start, consider following steps 2 – 9 one more time. 

After resetting the generator, manually perform the weekly test cycle by pressing the Manual key from the control panel. If it doesn’t run the test, diagnose the following seven parameters as explained in the next segment and ensure each is functioning properly.

If your generator still refuses to start or shows a warning indicator, it might be linked to the red light alert on your Generac control panel. That guide explains what each warning means and how to clear it safely.

What To Do If Generac Generator Won’t Start After The Weekly Test?

If your Generac generator fails to start after a weekly test, there are seven diagnostics you can do to troubleshoot. I have explained them in detail below:

Diagnosis 1: Check the fuel level

You must ensure that there is enough fuel in the tank. You can check the fuel level of the Guardian/home standby generators by integrating Generac’s Tank Utility propane monitor with the Mobile Link app. 

The utility monitor will notify you when to refuel the unit. Refuel the unit from the fuel port, which is located on the curbside of the unit, and start the generator again.

Diagnosis 2: Check the battery

The issue might be related to the battery, and in that case, you will see green and yellow LED lights turned on the side of the control board. The LCD screen of the control panel will also read “Inspect Battery.” If it does, then perform the following diagnostics:

• Wear safety gloves, open the side cover, and find out if it’s leaking acid. Disclaimer: If your skin comes in contact with the battery acid, it can cause chemical burns. Clean the battery terminals and the compartment if it’s leaking acid with a rug.

• Ensure that the battery is well-hydrated by taking off the lid and measuring the water level with the help of a hydrometer.
• Also, check the battery voltage. It shouldn’t read less than 12.5 V and more than 13.5 V.
• Finally, look at the date code on the top of the battery cover. Consider changing the battery if it’s older than 3-4 years.

Diagnosis 3: Check the oil level

Add oil if the oil level is low, and replace it if it’s dirty. You can check the condition of the oil and its level by opening the lid and using the dipstick inside the unit.

Here is a step-by-step instruction on how to check, replace and add oil to the Generac generator (Guardian or standby series):

Step 1: Disconnect the generator from the home’s main utility

Turn off the main circuit breaker in your house by switching it from the ON position to the OFF position.

Step 2: Shut down the unit’s power

Locate the Main Circuit Breaker, which is outside or at the top of the control panel, and flip the switch from the ON position to the OFF position. Now place the generator from the Auto mode to the OFF position, and this you can do by pressing the red button from the control pane

Step 3: Let it cool down

 Allow the unit to cool down for 5 – 10 minutes.

Step 4: Remove the dipstick

Gently pull out the orange head of the dipstick from the left side of the engine and wipe it with a clean rag.

Step 5: Read the dipstick

Put the dipstick back in and pull it out to read the level and identify the condition. The oil level should be between the “ADD” and “FULL” marks. Add oil if the level goes down to the “add oil” mark.

Step 6: Add oil

• First, you have to remove the front door. Lift up, tilt back, and pull over the front door out of the way to remove it.
• Twist the orange cap of the oil fill and remove.
• Add a Generac branded oil or a synthetic 5W30 oil inside the tube. 
• Recheck with the dipstick to ensure that the oil reaches the “FULL” mark and doesn’t over-exceed.

Step 7: Replace the oil cap

Take the orange cap and put it back on by rotating it.

Step 8: Close the front door

Close the door by sliding the two pins on the bottom into the two holes at the unit’s base. Lean forward, tilt up, and push down the door.

Step 9: Restart the generator

Press the green key from the control panel to place the generator into the auto position, and generator will start and run in about ten seconds. Allow the generator to come up to speed by waiting a few minutes, and then place the mainline circuit breaker from the off position back to the on position. Doing so will restore the power and restart the unit.

Step 10: Reconnect to the grid

Pull down the lid to close it and turn the latches on both sides of the unit to lock the door. Turn your home’s main circuit breaker back to ON by flipping it from the OFF position to the ON position.

If you want to know more about oil, here I compared some oils.

Diagnosis 4: Check the air filter

This is the least probable reason, but a clogged air filter can also prevent a Generac generator from starting. If you suspect the air filter is clogged, then you should check it. You can check the air filter’s condition by opening the unit’s lid and as shown in the following image.

After removing or replacing the air filter, you will notice a code on the control panel’s display screen, and you’ll need to hit the OFF button once and then the Enter key. Doing so will clear the code, and then press the Auto button.

The above image shows the air filter of the Guardian series and standby Generac generators. If you have a portable Generac generator, the air filter is located outside the unit.

In the case of a portable Generac generator, unscrew the air filter cover, remove the air filter by opening the cover, and clean the filter with soapy water.

Diagnosis 5: Check the spark plug

A faulty spark plug is another reason why the generator might fail to start after a weekly test. Most OEM technicians recommend changing the spark plug at least once a year. You can test the spark by using a spark tester. If the spark tester flashes red when the generator is running, it would indicate that there is no issue with the spark.

You can also understand whether it is necessary to replace the spark plug by checking the condition of the electrode. You don’t need to replace it if the electrode of the spark plug doesn’t look worn out. If you see surface rust on the electrode or if it looks worn out, you should change it.

Here is how to inspect the electrode and replace the spark plug:

Step 1: Follow steps 1 to 4 from the segment on checking the oil level.

Step 2: Remove the spark plug’s boot by gently pulling it.

Step 3: Remove the spark plug by using a socket wrench.

Step 4: Read the spark plug’s part number.

Step 5: Inspect the electrode.

If the electrode seems worn out and rusty, you either need to clean it or replace it with a new one.

Step 6: Take a new spark plug and thread it back into the spark plug housing.

Step 7: Tighten the spark plug by using the socket wrench.

Step 8: Reconnect the spark plug boot.

Step 9: Restart the generator with the same procedures as explained in step number 9 to 11 from the segment on checking the oil level.

Diagnosis 6: Drain the fuel tank

If the fuel has been sitting idle inside the generator for over a year, then you must drain it. 

Here is how to drain the fuel tank:

• Shut down the generator by following the steps mentioned in the above segments. 
• Next, locate the fuel tank, as shown in the image. 
• Make sure the fuel is turned off. 
• Loosen up the spring clamp by gently putting pressure on it with your hand or with pliers. 
• With the help of pliers, twist the hose and wiggle it to remove the fuel filter. 
• Attach an old hose and turn the fuel ON, and this should start draining the old gas.

Diagnosis 7: Clean or replace the dirty fuel filter and carburetor

After draining old gas, it is important to either replace the fuel filter as well as the carburetor with a new one every year or give them a thorough clean by following the above steps:

• Remove the air filter and the carburetor and soak them in a commercial solvent overnight.
• Clean off the solvent from the units by using a spray carb cleaner. Make sure to wear safety gloves and goggles when using spray carburetor cleaner.
• Get the cleaner into every passage and hole of the filter and the carburetor.
• Use low-pressure compressed air in order to dry the units.
• Reassemble them.

Conclusion

Finally, you must agree that it’s pretty easy to program your Generac generator for weekly tests. But one of the most popular complaints is that sometimes the generator might fail to restart after the test. If that’s the case, we have already discussed all the ways to troubleshoot it. If that doesn’t work, it is high time to contact the dealer or take support from a Generac-certified technician.

Frequently Asked Questions (FAQs):