The blinking lights on an Onan generator are error codes. The manufacturer uses these codes to communicate with consumers.
The lights are not always a bad thing. However, they should concern you because they typically appear when things have gone wrong. For instance, an Onan generator’s lights can blink because of the following:
- The engine oil is low. You can confirm this theory by looking at the dipstick. Don’t allow the oil level to fall below the recommended indicator on the dipstick.
- The battery connections are dirty.
- The battery connections are loose.
- The battery is dead or depleted. A depleted battery should concern you. You should find out why the generator has failed to charge the battery.
- The battery terminals are corroded.
- The filters are dirty and clogged.
- You’ve overloaded the generator.
- Two blinks point to a low oil pressure fault.
- Three blinks appear when the generator detects a service fault.
- Four blinks appear when cranking exceeds thirty seconds, but the engine has not started.
- Some models blink when they detect high temperatures. A generator’s work produces heat. You can’t transmit electricity through a medium without generating some warmth. However, excess heat should concern you. According to Vital Power, a generator’s operating temperature is 190 – 220 degrees. Check the manual to find your generator’s operating temperature. Determine whether the device has exceeded that threshold.
- The engine doesn’t have enough coolant. If the generator has a coolant leak, you should find and resolve it before adding more coolant.
- You have a blocked air inlet and outlet.
- The engine V belt is loose, worn out, or damaged.
- The spark plugs are dirty or worn out.
- The control board is corroded. Take a moment to determine whether it was exposed to moisture and corrosive chemicals.
- The fuel is old and stale. Old fuel will cause clogging.
- The generator has damaged wires. If you keep the unit in a basement or garage, don’t be surprised if pests sneak into the generator and chew through the lines. Damaged wires are arcing hazards.
- The oil pressure switch is stuck. The engine typically shuts down when this occurs.
- A defective inverter keeps overcharging the generator.
- The Onan generator cannot maintain the correct voltage levels.
- The engine is running too fast because of a bad carburetor, air leaks, broken governor, etc.
- Lights on the generator will blink when the controller fails to sense the output voltage.
- The cranking speed is low (Less than 180 RPM for two seconds).
- The generator may flash an error code when the engine stops without you commanding it. This can occur because of bad spark plugs and insufficient fuel.
- The Onan generator has the wrong frequency setting.
- The generator has a Microprocessor Rom section error.
| Generator Lights Flashing | Reason |
| 3 Times | 1. Fault shutdown 2. Service fault |
| 6 Times | The gas has grown stale, clogging the carburetor. This prevents the gas from reaching the engine, causing it to shut down. |
How To Troubleshoot Onan Generator Blinking Lights?
You can either remove the error code or fix the problem. These two options are not the same.
You can stop the blinking without solving the problem that caused it. But that is a mistake because any pre-existing fault in the Onan generator will worsen until you fix it. However, you shouldn’t be so quick to take the generator apart.
Onan will void your warranty if you tamper with their product. They will assume that your actions caused the fault, and you can’t prove otherwise. Therefore, you should respond to a flashing generator by taking the unit to an Onan dealership.
Let the company’s experts solve the problem. But what if that isn’t an option? If you trust your skills, you can apply the following solutions:
- Find the battery cable connections. Clean and tighten them. Otherwise, the status indicator lights won’t illuminate. If the generator won’t start despite your actions, recharge the battery.
- If the generator doesn’t respond because of a defective battery, replace it. Gen-Tech expects a generator’s battery to last three years if you perform regular maintenance. Therefore, if you’ve owned your generator battery for more than three years, don’t hesitate to replace it.
- If the generator is low on oil, add more. This problem is easy to troubleshoot. Use the dipstick to track the oil level. Don’t exceed the maximum indicator on the dipstick.
- If you think the control board is at fault, turn the switch off before pressing the reset button. This will eliminate some glitches by resetting the control board. Test the generator by turning the switch to run. If the error codes and flashing lights persist, replace the control board.
- If you suspect a faulty inverter, talk to an Onan dealer, especially if you’ve eliminated other potential culprits, such as insufficient fuel and clogged filters. If you don’t want to void your warranty, let the experts resolve this issue.
- If the code points to under voltage, disconnect the equipment you don’t need while the battery charger runs. It is worth noting that under voltage can occur because of a fuel deficiency.
- If you’ve seen a code (14) that points to over-frequency, clean the carburetor. Wait for the generator to cool down before retrieving the carburetor and placing the part in a cleaning solution. Replace a damaged carburetor.
- If you suspect under-frequency (Code 15), inspect the governor. You may have installed it poorly or connected it to the wrong spot. You should also look for loose connections. Try performing a reset.
- If the error codes point to a defective low-oil pressure cutoff switch, a layperson cannot fix this problem. Leave it to an Onan dealer or any licensed technician you trust. You should do the same for a controller that can’t sense the output voltage.
- If the cranking speed is too low, find the battery and clean the connections. If that doesn’t work, recharge the battery. If the symptoms persist, replace the battery.
- Check the engine oil. If the viscosity is wrong, flush the system and add new oil.
- If you suspect a Microprocessor error, take the generator to an expert.
- Take a generator with a short circuit in the fuel injector to an Onan technician.
- Look for clogged pathways in the generator and unblock them. Gas can clog the passageways when it ages and becomes varnish. This prevents the gas from reaching the engine. This can happen when you leave the generator in storage for long periods.
- If the generator produces too much smoke, clean or replace the air filter.
- If pests keep chewing through the wires, identify a clean, safe storage space for the generator. You can also set traps for rodents. Don’t start the generator without replacing the cables.
- Clean dirty spark plugs.
- Replace weak spark plugs.
Believe it or not, blinking lights are relatively easy to troubleshoot. Why? Because the Onan generator will also display error codes. You can use the error codes to identify the fault causing the blinking lights if you have a manual.
The manual will show you the problems you can solve yourself and the ones that require an expert.