Discover what Kohler Generator Code 28 means, its common causes, and effective solutions. Quickly troubleshoot and fix this error with our straightforward guide.
Head of Content, D. Gorenko
Updated June, 5
If you see a Code 28 error on your generator's control panel or screen, it generally means the generator is not sensing a signal from the magnetic pickup (MPU) or engine speed sensor. In simple terms, your generator uses a special sensor to detect how fast the engine is running. This information is essential for the generator to operate safely and efficiently. When there’s a Code 28, the generator can’t “see” the engine speed, so it often won’t run or will shut down to prevent damage. This issue is commonly labeled as “Loss of Engine Speed Signal” or “No MPU Signal.”
Generators use a component known as a magnetic pickup, or MPU, to track engine speed. This sensor reads the spinning of the engine’s crankshaft and sends this information to the controller. The controller uses that data to make important decisions, like adjusting fuel delivery, voltage adjustment, and keeping your generator running safely. When the controller loses this signal, it throws up the Code 28 to alert you something is wrong.
There are several reasons why you might see a Code 28 error in generators in places like St Louis or Nashville, whether it’s in a basement, outside a local business, or on a large commercial property. Main causes include:
When your generator in St Louis or Nashville shows a Code 28, it’s a protective measure. If the generator can’t tell how fast its engine is spinning, running it could cause severe engine damage, cause it to run dangerously fast (overspeed), or not generate power properly. Therefore, most generators will shut down or refuse to start if this error appears.
If you’re unsure about handling electrical equipment, it’s always safest to contact a professional technician familiar with generators in both St Louis and Nashville.
However, many people can perform a few basic troubleshooting steps:
For most customers in St Louis and Nashville, if basic steps don’t work, calling a qualified generator technician is the best and safest option.
To avoid encountering Code 28 errors in the future, it’s helpful to have your generator professionally maintained, especially in areas like St Louis and Nashville where weather and air quality can influence equipment longevity. Professional technicians will check sensor alignment, wiring health, and clean away debris during routine service, keeping everything running smoothly.
A Code 28 error on your generator is a warning that the engine speed sensor’s signal has been lost. This means your generator can’t safely monitor or control its engine, so it will usually shut down or won’t start. In almost all cases, you’ll either need basic checks on wires and sensor cleanliness, or call for a professional to repair or replace components. If you’re in St Louis or Nashville, make sure to address this message quickly to keep your generator ready for emergencies.
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The Code 28 error on a Kohler generator signifies a "Low Battery Voltage" or "Battery Voltage Below Limit" issue. This means the generator's control system has detected that the battery supplying power to the generator's starting system has insufficient voltage to function properly. Generators need a healthy battery to start the engine, operate safety features, and communicate with monitoring equipment.
Everyday reasons this error appears include:
1. Safety First: Stop and Isolate Generator Power
Before doing any work on the generator, always turn off the generator and disconnect main power if possible. If you are unsure, contact a professional in St Louis or Nashville to help ensure you work safely.
2. Visually Inspect the Battery and Connections
Check the battery for any visible damage, swelling, or leaking. Look at the battery terminals and cables for corrosion (white or greenish deposits), loose connections, or frayed wires. Tighten any loose connections and clean corrosion off the terminals using a wire brush and a baking soda-water solution. Be sure all connections are solid and secure.
3. Test the Battery Voltage
Using a basic multimeter or voltage tester, measure the battery voltage at the terminals. For most Kohler generators, a healthy 12V battery should read 12.6V or higher when fully charged. If voltage reads below about 12.0 volts, the battery is low and likely causing the Code 28 error. If the battery is swollen, leaking, or very old, it should be replaced.
4. Attempt to Recharge or Jump-Start the Battery
If the battery voltage is low but the battery is otherwise in decent shape, try to recharge it with a certified battery charger. If needed to test operation, you can jump-start using an external jump box or another battery. Once started, clear the code on the generator controller and observe whether the generator continues to run normally and the voltage stays up.
5. Inspect the Battery Charger and Power Source
Generators usually have a built-in battery charger that keeps the battery topped off when not running. Make sure the charger is powered (check its status indicator), plugged in, and connected securely to both power and the battery. Also, ensure the wall outlet or breaker feeding the charger has not tripped. If the charger is faulty, you may need to replace it or have an electrician repair the circuit.
6. Examine Environmental and Usage Factors
Low use, extraordinarily cold weather, or long power outages like sometimes experienced in St Louis or Nashville can impact battery performance. If your generator sits unused for months, consider a battery maintainer to prevent drain. For cold climates, a battery heater may be needed.
7. Clear the Code and Retest Generator Operation
Once you resolve the low battery voltage (by charging, cleaning, or replacing the battery), clear the Code 28 error on your generator controller. You may need to press a reset button or cycle the main switch. Then, test the generator by running it through a self-test or manual start to guarantee the problem is fully fixed.
8. If Issues Persist, Call a Professional Generator Technician
If after all these steps the Code 28 error remains, or the battery continues to lose charge rapidly, there could be a deeper electronic or alternator charging problem. At this stage, reach out to a trained generator technician servicing St Louis or Nashville to diagnose internal electrical issues or replace worn-out components safely.
If you take these steps, it's very likely you'll resolve the Code 28 error on your Kohler generator and restore reliable backup power for your property. Regular battery care is the number one way to prevent generator starting problems and avoid last-minute emergencies.
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A Code 28 error on a Kohler generator almost always means there is a problem with the loss of the generator's battery charging system. In simple words, the generator isn't able to keep its own battery charged. Everything in the generator that requires electricity—to start, to run the electronics, or even for remote notifications—relies on this battery, so the system checks constantly whether the battery is being charged properly while the generator runs. When it senses it’s not getting the correct charge, it will display the Code 28 error. Residents and business owners in St Louis and Nashville frequently encounter this error, especially during hot summers or cold winters when battery and charging issues are common.
The Code 28 error can show up on Kohler generators due to a variety of reasons. The most common are:
The generator checks the voltage (the electrical pressure) at the battery terminals. Normally, this should be above 12.5 volts when the generator is off, and around 13.5-14.5 volts while charging. If the control board notices the voltage isn’t rising when the generator is running, it realizes the charging system isn’t working right. That’s when it displays Code 28 to alert the owner that something’s wrong with battery charging.
Ignoring a Code 28 warning can lead to a dead battery, which means your generator won’t be able to start when the power goes out—a risk both to residential homes with sensitive electronics and to commercial businesses relying on uninterrupted power. In areas like St Louis and Nashville, where storms and outages can be frequent, it’s especially important to know why this error shows up.
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Brentwood, MO
1025 Hanley Industrial
Brentwood, MO 63144
Nashville, TN
45 Willow St.
Nashville, TN 37210
St Louis Location
(314) 664-3011
St Louis Location
1025 Hanley Industrial Brentwood, MO 63144
Nashville Location
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Nashville Location
45 Willow St Nashville, TN 37210
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