US Motor Power – Small Engine Repair Database

Blog

  • Generac Error Code 1200 Overspeed Explained & Troubleshooting

    What does this code mean? Generac error code 1200 indicates the generator’s engine is running faster than its normal speed for a sustained period, which can damage the unit if not addressed.

    The Generac 1200 error code is an overspeed alarm that signals your generator’s engine frequency has exceeded safe limits for more than three seconds. This means the engine is spinning faster than it should—above 72Hz on a 60Hz model (common in the US) or above 60Hz on a 50Hz model (used in other countries). This prolonged overspeed condition can cause serious damage if not corrected promptly.

    The most common cause of this overspeed is a problem with the generator’s stepper motor or mixer assembly. These components regulate the engine speed by controlling the fuel and air mixture. If the stepper motor becomes unplugged, stuck, or malfunctions, it can cause the engine to rev too high.

    Diagnostic Checklist

    1. Inspect the Stepper Motor Connection: Check that the stepper motor plug is securely connected. A loose or unplugged connector can cause overspeed.
    2. Look for Physical Obstructions: Examine the mixer assembly for any debris or jams that could prevent proper movement.
    3. Reset the Generator: Turn the unit off, wait a few minutes, and restart to see if the error clears.
    4. Check Engine Oil Level: Low oil can cause engine performance issues; ensure oil is at the recommended level.
    5. Inspect the Air Filter: A clogged air filter can affect engine speed control; clean or replace it if dirty.
    6. Verify Battery Voltage: A weak 12V battery may cause erratic control signals; test and recharge or replace as needed.
    7. Review Control Board Connections: Look for loose or corroded wiring around the control board and stepper motor.
    8. Consult the Owner’s Manual for Specific Reset Procedures: Follow any model-specific steps recommended by Generac.

    When to Call a Pro

    If you’ve completed the above checklist and the overspeed alarm persists, or if you notice any of the following, it’s time to contact a professional technician:

    • The generator engine runs at dangerously high speeds immediately upon startup.
    • You hear unusual noises such as rattling or knocking during operation.
    • The unit frequently shuts down or fails to start after the overspeed alarm.
    • There are visible signs of damage or burnt components near the stepper motor or control board.
    • You are uncomfortable performing electrical or mechanical inspections yourself.

    Parts You May Need

    • Spark plug
    • Oil filter
    • 12V battery
    • Stepper motor or mixer assembly (replacement recommended by a technician)
    • Air filter

    FAQ

    What causes the Generac 1200 overspeed error?

    This error usually happens when the stepper motor or mixer assembly malfunctions, gets unplugged, or jams, causing the engine to run faster than normal.

    Can I reset the 1200 overspeed alarm myself?

    Yes, you can try turning off the generator, waiting a few minutes, and restarting it. However, if the problem persists, further inspection or professional help is needed.

    Is it safe to run the generator with a 1200 overspeed alarm?

    No. Running the generator while it is overspeeding can cause severe engine damage. It’s important to address the issue promptly.

    What professional repairs are typically needed for this error?

    A technician may need to repair or replace the stepper motor or mixer assembly and check the control board wiring to restore proper engine speed control.

    Disclaimer: This article provides general information about the Generac 1200 overspeed error code. Always refer to your generator’s specific manufacturer manual for detailed troubleshooting and safety instructions.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Generac Error Code 1100 Overcrank: What It Means and How to Fix It

    Generac error code 1100 means your generator’s engine is cranking but failing to start, usually due to fuel supply or maintenance issues.

    If your Generac Evolution 1.0 or 2.0 series standby generator shows error code 1100, labeled as “Overcrank,” it indicates the controller is attempting to start the engine but the engine isn’t firing up. The system confirms the starter motor is turning the engine over, but the engine doesn’t catch and run. This is a common alarm that usually points to problems with fuel delivery or routine maintenance items.

    What Causes Overcrank (Error Code 1100)?

    The most frequent reasons for this error are:

    • Empty or shut-off fuel supply: If your generator runs on propane (LP gas), the tank might be empty or the valve closed. For natural gas, the supply could be interrupted.
    • Fuel system blockages or leaks: Clogged fuel filters or faulty fuel lines can prevent proper delivery.
    • Maintenance-related issues: Dirty spark plugs, old fuel, or valve problems can keep the engine from starting.
    • Starter motor protection: On 8kW and 9kW models, the controller limits the number of start attempts to 10 to avoid damaging the starter. If it reaches this limit, the alarm triggers.

    Diagnostic Checklist

    Before calling a technician, try these steps in order to potentially fix the issue yourself:

    1. Check the fuel supply: Ensure your propane tank has gas or natural gas is flowing. Open any closed valves.
    2. Inspect fuel lines and connections: Look for leaks, kinks, or blockages in the fuel hose or piping.
    3. Examine the fuel filter: Replace it if it looks dirty or clogged, as restricted fuel flow can prevent starting.
    4. Test the battery voltage: A weak 12V battery may crank but not provide enough power for ignition.
    5. Check spark plugs: Remove and inspect for fouling or wear; clean or replace as needed.
    6. Verify oil level and quality: Low or dirty oil can cause engine protection circuits to prevent starting.
    7. Reset the controller: Power down the generator and restart after a few minutes to clear temporary faults.
    8. Review maintenance history: If valves or other engine components haven’t been serviced recently, schedule maintenance.

    When to Call a Pro

    Contact a qualified generator technician if you notice any of the following:

    • The generator repeatedly fails to start even after fuel and battery checks.
    • You smell fuel leaks or detect strong propane odors near the unit.
    • The error code persists after resetting the controller multiple times.
    • There are unusual noises during cranking or visible engine damage signs.
    • You are uncomfortable performing fuel system or electrical checks yourself.

    Parts You May Need

    FAQ

    What does the Overcrank error code 1100 mean on my Generac generator?

    It means the generator’s engine is turning over but failing to start, often due to fuel issues or maintenance needs.

    How can I fix the Overcrank error myself?

    Check your fuel supply, inspect fuel lines and filters, verify battery condition, and ensure spark plugs and oil are in good shape.

    Why does my Generac limit the number of start attempts?

    To protect the starter motor from damage, the controller restricts start attempts to 10 on certain models before triggering the Overcrank alarm.

    When should I call a professional technician for error 1100?

    If the generator keeps failing after basic checks, you detect fuel leaks, or feel unsure about troubleshooting fuel or electrical systems, call a pro.

    Disclaimer: This information is general guidance only. Always follow the manufacturer’s manual and safety instructions for your specific Generac model.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Cummins Onan Code 14: Overfrequency Alarm

    Plain English: Code 14 means your Cummins Onan generator’s engine is running faster than it should, and the governor system can’t bring it back down to the correct speed.

    What Code 14 Actually Means

    When your generator displays Code 14, it’s telling you that the engine frequency—essentially how fast the engine is turning—has climbed above the rated operating speed. In a properly functioning generator, an internal governor automatically adjusts fuel flow to keep the engine running at exactly the right speed. When Code 14 appears, that governor has lost the ability to control the engine’s RPM, and the engine is spinning faster than designed.

    This is different from a simple overspeed shutdown. Code 14 is an alarm that indicates the governor itself isn’t responding correctly to bring the frequency back into the normal range. Left unchecked, an overfrequency condition can damage the alternator, stress internal engine components, and potentially create a safety hazard.

    Common Causes of Code 14

    Governor Control Cable Issues
    The mechanical linkage that connects your governor to the fuel injection system can become loose, bent, or disconnected. Even a small amount of slack in this cable prevents the governor from properly throttling back the engine when speed increases. Over time, vibration and normal wear can gradually loosen these connections.

    Fuel Injection System Problems
    If the fuel injectors are stuck open or the fuel control system isn’t responding to governor commands, the engine will keep receiving too much fuel and continue accelerating. A stuck injector or a fuel control solenoid that has failed can lock the system into a high-fuel state.

    Governor Spring Failure
    The governor relies on internal springs to return to a neutral position when engine speed increases. If these springs weaken, break, or become stuck due to corrosion or debris, the governor loses its ability to regulate speed. This is an internal issue that requires professional service.

    Air Intake Restrictions
    A severely clogged air filter or blocked intake can sometimes cause unusual governor behavior. While less common as a sole cause of Code 14, a dirty air filter should always be checked as part of your diagnostic process.

    Electrical Faults in Governor Control
    Some Onan generators use electronic components to assist governor operation. A faulty sensor, corroded connector, or damaged wiring in the governor circuit can prevent the system from responding to speed changes.

    Diagnostic Checklist

    1. Check the air filter. Remove and inspect the air filter element. If it’s dark, clogged, or visibly restricted, replace it. A clean air filter is the easiest first step and costs just a few dollars. Run the generator for a few minutes after replacement to see if the code clears.
    2. Inspect the governor control cable. Locate the mechanical linkage running from the governor to the fuel injection system (consult your manual for the exact location on your model). Look for loose bolts, bent brackets, or disconnected ends. Gently wiggle the cable to ensure it moves freely without binding. Tighten any loose fasteners with a wrench or socket set.
    3. Check fuel quality and level. Stale or contaminated fuel can affect engine response. If your generator has been sitting for months, drain the old fuel and replace it with fresh gasoline or diesel (depending on your model). Make sure the fuel tank is adequately filled—a low fuel level can sometimes trigger unusual governor behavior.
    4. Look for visible corrosion or debris. Inspect all visible governor linkages, springs, and connections for rust, dirt, or debris. Use a soft brush or compressed air to gently clean away any buildup. Do not force any corroded parts; if they’re stuck, this indicates internal damage requiring professional service.
    5. Test under no-load conditions. If safe to do so, start the generator without any electrical load connected. Listen for unusual engine noise or vibration. A generator that runs smoothly at idle but exhibits Code 14 under load may have a different root cause than one that shows the error immediately. Document what you observe.
    6. Check all electrical connections. Examine the battery terminals, alternator connections, and any wiring harnesses related to the governor system for corrosion, loose terminals, or damaged insulation. Clean corroded terminals with a wire brush and tighten any loose connections.
    7. Review your maintenance history. If the generator has not been serviced recently, the governor system may simply need professional cleaning and adjustment. Note the hours on your generator and when it was last serviced by a technician.

    When to Call a Pro

    Stop troubleshooting and contact an authorized Cummins Onan dealer immediately if you observe any of the following:

    • The engine continues to accelerate even after you move the load control or throttle to the lowest setting.
    • The Code 14 alarm persists after you’ve checked the air filter, fuel, and visible linkages.
    • You notice the governor cable is bent, kinked, or visibly damaged.
    • The engine makes grinding, knocking, or unusual metallic noises while Code 14 is active.
    • The generator shuts down abruptly or the frequency fluctuates wildly between high and low.
    • You see fuel leaking from the injection system or governor area.
    • Any internal governor components appear corroded, stuck, or broken when you inspect them.

    Continuing to operate a generator with an unresolved Code 14 can damage the alternator windings, stress the engine block, and potentially create a fire hazard. Professional service is not optional in these cases—it’s a safety requirement.

    Parts You May Need

    • Air filter element
    • Fresh fuel (gasoline or diesel, depending on your model)
    • Fuel filter (if your model has a replaceable cartridge)
    • Governor control cable (if the existing one is damaged)
    • Fuel injector cleaning kit or replacement injectors
    • Governor spring kit (if internal springs have failed)
    • Electrical connectors and wiring harness repair kit

    Frequently Asked Questions

    Q: Can I keep running my generator if Code 14 appears occasionally?

    A: No. Code 14 indicates a loss of governor control, which means the engine is running faster than safe. Even occasional appearances of this code signal a developing problem. Continuing to operate the generator risks damage to the alternator and engine. Have it inspected by a technician before running it again under load.

    Q: Is Code 14 the same as an overspeed shutdown?

    A: Not quite. An overspeed shutdown is a safety feature that kills the engine if it exceeds a maximum RPM threshold. Code 14 is an alarm that the governor itself has failed to maintain the correct speed—it’s a step before the overspeed protection kicks in. Code 14 means the governor is not working; overspeed shutdown means the engine has exceeded safe limits.

    Q: Why would the governor suddenly fail if my generator was working fine yesterday?

    A: Governor failure is rarely sudden. Usually, a loose cable, stuck linkage, or fuel system issue develops gradually. Vibration, corrosion, and wear accumulate over time. However, a sudden loss of fuel pressure, a broken spring, or a failed electronic sensor can cause Code 14 to appear without warning. This is why regular maintenance and prompt attention to warning signs are important.

    Q: Can a clogged fuel filter cause Code 14?

    A: A severely clogged fuel filter can cause the engine to run lean and behave unpredictably, but it’s more likely to cause the engine to stall or run rough than to trigger Code 14. However, a clogged filter should always be replaced as part of your troubleshooting process, since it can contribute to governor control issues and fuel system problems.

    Disclaimer

    This article provides general information about Cummins Onan Code 14 and is intended for educational purposes only. It is not a substitute for your generator’s official manual or professional service. Always consult the manufacturer’s documentation for your specific model before attempting any repairs or maintenance. If you are unsure about any step, contact an authorized Cummins Onan dealer. Improper diagnosis or repair can result in equipment damage, personal injury, or fire hazard.

    For detailed technical specifications and official guidance, refer to the Cummins Onan service documentation available at cummins.com.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Cummins Onan Code 13: Undervoltage Alarm Fix

    Plain English: Your Cummins Onan generator is detecting that it cannot maintain the correct output voltage, usually because you’re trying to run too many high-power appliances at the same time.

    What Code 13 Means

    When your Cummins Onan generator displays Code 13, the onboard controller is signaling an undervoltage condition. This means the generator’s output voltage has dropped below the rated level it’s designed to maintain. Unlike a complete shutdown, Code 13 is an alarm—your generator is still running, but the electrical system is stressed.

    The root cause is almost always excessive electrical load. Your generator has a maximum power output (measured in watts or kilowatts). When the combined demand from all connected appliances exceeds what the unit can safely deliver, voltage sags. This is especially common when high-inrush devices like air conditioners and battery chargers start up simultaneously.

    Why This Happens

    Generators don’t have infinite power reserves. Each model is rated for a specific maximum output. When you connect appliances, they draw current from that pool of available power. Some devices—particularly motor-driven equipment—demand a large surge of current at startup. Air conditioners and battery chargers are notorious for this.

    If your total connected load exceeds the generator’s capacity, the voltage regulator cannot maintain the proper output voltage. The controller detects this drop and triggers the Code 13 alarm to protect your equipment from damage due to low voltage.

    Think of it like a water system: if too many faucets run at once, the pressure drops. Your generator’s voltage works the same way.

    Diagnostic Checklist

    1. Check your generator’s rated capacity. Look at the nameplate on your unit or consult your owner’s manual. Write down the maximum kW or kVA rating. This tells you the absolute ceiling of power available.
    2. List all connected appliances and their power draw. Check the labels on major devices (air conditioner, refrigerator, water heater, battery charger, microwave). Most appliances show watts or amps. Add them up. If the total exceeds your generator’s rating, you’ve found the problem.
    3. Turn off the air conditioner and battery charger. These are the most common culprits. Restart the generator. If Code 13 clears, you’ve confirmed the issue is load-related, not a mechanical fault.
    4. Stagger high-power device startup. Don’t start the AC and battery charger at the same time. Turn on one, wait 30 seconds, then turn on the next. This spreads the inrush current over time and prevents voltage collapse.
    5. Reduce overall connected load. Unplug non-essential devices. Turn off space heaters, water heaters, or other resistive loads that aren’t critical. Aim to stay 20–30% below your generator’s rated capacity for safe operation.
    6. Inspect fuel level and fuel quality. A generator running on low fuel or degraded fuel cannot maintain proper voltage regulation. Fill the tank and ensure fuel is fresh (less than 30 days old for gasoline, or use fuel stabilizer for longer storage).
    7. Check for loose connections at the generator terminals. Corroded or loose battery cables and output terminals increase resistance, causing voltage drop. Clean any corrosion with a wire brush and tighten all connections firmly.
    8. Verify the generator is running at full throttle. Some models have a choke or throttle control. If the engine is running slowly, it cannot generate rated voltage. Ensure the throttle is set to full speed and the engine is warmed up.

    When to Call a Pro

    If you’ve followed the diagnostic checklist and Code 13 persists even with minimal load connected, the problem may be internal:

    • The voltage regulator is faulty and cannot maintain output voltage even at light load.
    • The alternator or generator head is failing.
    • Internal wiring or connections are corroded or damaged.
    • The engine is not running at full RPM due to carburetor, governor, or ignition issues.

    Also seek professional help if you notice:

    • Code 13 appears even when only one appliance is running.
    • The generator sounds rough or is misfiring.
    • You smell fuel or see fuel leaking.
    • The unit shuts down unexpectedly after the alarm appears.

    Parts You May Need

    • Fuel stabilizer (for old fuel)
    • Wire brush or battery terminal cleaner
    • Fresh gasoline or diesel (depending on your model)
    • Replacement fuel filter (if fuel quality is suspect)
    • Voltage regulator (if diagnosis points to regulator failure)
    • Alternator or generator head (in rare cases of internal failure)

    Best Practices to Avoid Code 13

    Once you’ve resolved the immediate alarm, adopt these habits:

    Know your limits. Keep a list of your generator’s rated capacity and major appliance power draws posted near your electrical panel or generator. Before plugging in a new device, check if it will fit within your available capacity.

    Prioritize critical loads. Decide which appliances are essential (refrigerator, water pump, heating/cooling) and which are optional (entertainment, non-essential chargers). Run essential loads first, then add optional loads only if capacity allows.

    Use a heavy-duty extension cord with a power meter. A plug-in watt meter (available at hardware stores) lets you measure real-time power draw. This takes the guesswork out of load management.

    Maintain the generator regularly. Clean fuel, fresh oil, and a clean air filter ensure the engine runs at full efficiency. A weak engine cannot generate rated voltage.

    Avoid simultaneous startup of large motors. If you must run both an air conditioner and a water heater, start them 30–60 seconds apart. This prevents the inrush current spike that triggers Code 13.

    FAQ

    Q: Is Code 13 dangerous?

    A: Code 13 is an alarm, not an immediate shutdown. However, sustained low voltage can damage sensitive electronics and reduce the lifespan of motors. It’s a warning to reduce load, not an emergency. That said, don’t ignore it—address the cause promptly.

    Q: Can I ignore Code 13 and keep running?

    A: Technically, the generator will continue running, but you’re operating outside safe parameters. Low voltage can cause appliances to malfunction, overheat, or fail prematurely. It’s better to reduce load and clear the alarm.

    Q: Why does Code 13 appear when I turn on the air conditioner?

    A: Air conditioners draw enormous current at startup—often 2–3 times their running current. If your generator is already near capacity, the AC startup surge pushes it over the edge. This is the most common scenario for Code 13 in RVs and standby systems.

    Q: Will upgrading to a larger generator fix this?

    A: If you consistently exceed your current generator’s capacity, a larger unit is a long-term solution. However, first confirm that the issue is truly insufficient capacity and not a regulator or fuel problem. A technician can help you right-size an upgrade.

    Disclaimer

    This article provides general information about Code 13 on Cummins Onan generators. It is not a substitute for your generator’s owner’s manual or professional service. Always refer to the manufacturer’s documentation for your specific model before attempting repairs or modifications. If you are unsure about any diagnostic step, consult a qualified technician. Improper generator operation or maintenance can result in equipment damage, personal injury, or property loss.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Code 35 Control Card Failure – Cummins Onan Generator

    Plain English: Code 35 indicates that your generator’s control card—the computerized brain that runs your unit—detected a memory error during its startup self-test and cannot operate safely.

    What Code 35 Means

    When your Cummins Onan generator displays Code 35, it’s telling you that the microprocessor’s internal memory (called EEPROM) failed a diagnostic check. Think of the EEPROM as the control card’s permanent storage—it holds the instructions and settings the generator needs to start and run. If that memory becomes corrupted or unreadable, the control card shuts down the generator to prevent damage.

    This is a serious alarm, not a warning. Your generator will not start or run while Code 35 is active. The control card is essentially saying, “I can’t trust my own memory, so I’m stopping everything until this is fixed.”

    What Causes Code 35

    Control card memory failure can happen for several reasons:

    • Power surges or electrical spikes: A lightning strike, utility fault, or sudden voltage surge can corrupt the microprocessor’s memory.
    • Age and component wear: EEPROM chips can degrade over time, especially in generators that run frequently or in harsh environments.
    • Manufacturing defect: Rarely, a control card ships with a faulty memory chip.
    • Loose or corroded connections: Poor electrical contact between the control card and the generator’s wiring harness can cause intermittent power to the microprocessor, corrupting data.
    • Overheating: If the generator runs in extreme heat or the control card enclosure is blocked, heat stress can damage the EEPROM.

    Diagnostic Checklist

    Before you call an authorized dealer, try these steps in order. They’re listed from cheapest and easiest to more involved.

    1. Check the display and note the exact code. Make sure Code 35 appears consistently, not intermittently. Write down when it appeared and what the generator was doing (starting up, running under load, etc.). This information helps the technician.
    2. Perform a soft reset. Turn off the generator’s main disconnect switch, wait 30 seconds, then turn it back on. Sometimes a transient glitch can be cleared by a clean restart. If Code 35 clears and doesn’t return, monitor the unit closely over the next few days.
    3. Inspect the control card enclosure for water or corrosion. Open the generator’s control panel (consult your manual for the exact location and procedure). Look for moisture, rust, or white/green corrosion on the circuit board or connectors. If you see water inside, the unit needs to dry out and may need professional cleaning. Do not attempt to dry it with heat; let it air-dry in a warm, dry place for 24–48 hours, then try again.
    4. Check all visible wiring connections to the control card. Look for loose, corroded, or disconnected terminals. Gently wiggle connectors (with the generator off) to ensure they’re fully seated. Corrosion can be cleaned with a small brush or contact cleaner, but be careful not to damage delicate pins.
    5. Verify the generator has adequate ventilation. Make sure cooling air can flow freely around the control card enclosure. Remove any debris, leaves, or obstructions. If the generator is in a confined space, move it to a well-ventilated area and try a restart.
    6. Check for recent electrical storms or power anomalies. If Code 35 appeared right after a lightning strike, power outage, or utility work in your area, a surge may have damaged the control card. This is a strong indicator that the card itself needs replacement.
    7. Attempt a manual reset if your model supports it. Some Onan generators allow you to clear fault codes via a menu option on the display. Consult your owner’s manual for the exact procedure. This rarely works for Code 35, but it’s worth trying if the option exists.

    When to Call a Pro

    Contact an authorized Cummins Onan dealer immediately if:

    • Code 35 persists after a soft reset and the steps above.
    • You see water, corrosion, or burn marks inside the control card enclosure.
    • The code appeared after a lightning strike, power surge, or electrical storm.
    • The generator has been in service for many years (10+) and Code 35 is your first major fault—the control card may simply be worn out.
    • You are uncomfortable opening the generator’s control panel or inspecting electrical connections.

    Code 35 almost always requires control card replacement. This is not a repair that homeowners should attempt, as it involves microprocessor-level diagnostics and reprogramming. An authorized dealer has the tools and firmware to replace the card and ensure it’s properly configured for your specific generator model.

    Parts You May Need

    If the control card must be replaced, the dealer will supply and install:

    • Replacement control card (specific to your model)
    • Wiring harness connectors (if damaged)
    • Thermal paste or sealant (for enclosure resealing)

    You typically cannot order these parts yourself; they must be sourced and programmed by an authorized dealer.

    Frequently Asked Questions

    Can I clear Code 35 by disconnecting the battery?

    No. Unlike some fault codes that clear when power is removed, Code 35 is stored in the control card’s permanent memory (EEPROM). Disconnecting the battery will not erase it. The code will return as soon as the generator restarts.

    Is Code 35 covered under warranty?

    That depends on your generator’s age and the cause of the failure. If the control card is defective due to manufacturing, it may be covered. If it failed due to a power surge or water damage, warranty coverage is less likely. Contact your dealer with your model number and serial number to check your specific warranty status.

    Can I use my generator while Code 35 is displayed?

    No. The control card will not allow the generator to start or run while Code 35 is active. This is a safety feature. Attempting to bypass or ignore the code can result in damage to the engine or other components.

    How much does a control card replacement cost?

    Control card replacement typically ranges from $300 to $800 in parts and labor, depending on your generator model and local service rates. Contact your authorized dealer for an exact quote. Some extended warranties or service plans may cover part or all of this cost.

    Final Notes

    Code 35 is one of the more serious faults your Onan generator can report, but it’s also one of the most straightforward to diagnose: the control card has detected a problem with itself and is shutting down to protect your equipment. In most cases, the solution is a replacement control card from an authorized dealer.

    If you’ve recently experienced a power surge, lightning strike, or water exposure, Code 35 is almost certainly the result. If the code appeared out of the blue on an older generator, the control card may have simply reached the end of its service life.

    Always consult your generator’s owner’s manual for model-specific information and procedures. This article provides general guidance; your manual is the authoritative source for your equipment.

    Disclaimer: This article is general educational information about generator error codes and is not a substitute for professional service or your manufacturer’s manual. Always refer to your Cummins Onan owner’s manual for model-specific troubleshooting and safety procedures. If you are unsure about any step, contact an authorized Cummins Onan dealer. Improper diagnosis or repair can result in equipment damage or personal injury.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Code 29: High Battery Voltage (Cummins Onan)

    Plain English: Your generator’s battery charging system is pushing too much voltage into the battery bank—more than 19 volts—and the onboard computer is shutting down to prevent damage.

    What Causes Code 29?

    Cummins Onan generators monitor battery voltage continuously. When the voltage climbs above 19 volts, the system triggers an alarm and stops the generator to protect the battery and electrical components. This almost always comes down to one of two issues: the batteries are wired incorrectly, or the charger is set too aggressively.

    Most RV and standby generators run on a 12-volt battery system. If those batteries accidentally get connected in series (end-to-end, like a flashlight), the voltage doubles to 24 volts—well above the 19-volt threshold. Even if they’re wired correctly in parallel, a boost-charge setting that’s too high can push voltage into dangerous territory.

    Diagnostic Checklist

    1. Check the battery connections visually. Open the battery compartment and look at how the cables connect. In a parallel setup, both positive terminals connect together, and both negative terminals connect together. In series, one positive connects to the other battery’s negative, then the remaining positive and negative go to the generator. If you see the series configuration, that’s your problem. Take a photo if you’re unsure, and compare it to your owner’s manual.
    2. Measure the battery voltage with a multimeter. Set a digital multimeter to DC voltage and touch the red probe to the positive battery terminal and the black probe to the negative. A healthy 12-volt battery system should read 12.5 to 14.5 volts at rest. If you’re seeing 19+ volts, the charger is overcharging. If you’re seeing 24+ volts, the batteries are in series.
    3. Review the battery boost-charge rate setting in the generator menu. Access the control panel (usually a small LCD screen on the generator or a remote panel in your RV). Navigate to battery settings or charger settings—the exact path varies by model. Look for “boost charge,” “charge rate,” or “battery voltage set point.” If it’s set to maximum, try reducing it by one or two levels and restart the generator.
    4. Verify the battery bank size and type. Check your owner’s manual or the battery labels. Cummins Onan systems are designed for specific battery capacities. If you’ve recently added extra batteries or replaced them with a different type, mismatched batteries can cause voltage regulation problems. Mixing old and new batteries, or different brands, sometimes causes issues too.
    5. Inspect battery cables for corrosion or loose connections. Even if the wiring diagram is correct, a corroded or loose connection can cause the charging system to “see” a false voltage reading. Clean any white, blue, or green corrosion off the terminals with a wire brush and a baking soda solution. Tighten all cable connections by hand, then with a wrench if needed.
    6. Check for a faulty battery charger or regulator. If voltage is still climbing after you’ve confirmed correct wiring and reduced the boost setting, the internal charger or voltage regulator may be failing. This is not a DIY fix—you’ll need a technician to test or replace the charging module.
    7. Confirm the generator software is current. Some Cummins Onan models have firmware updates that fix voltage-regulation bugs. Check the manufacturer’s website or contact a dealer to see if your model has any available updates. A technician can usually apply these during a service visit.

    When to Call a Pro

    Stop troubleshooting and contact a qualified technician if:

    • You measure voltage consistently above 19 volts even after reducing the boost-charge rate to its lowest setting.
    • The batteries are correctly wired in parallel, but the alarm keeps returning after a restart.
    • You notice the battery getting hot to the touch, or you smell rotten eggs (a sign of battery acid boiling off).
    • The generator won’t start at all, or starts but immediately shuts down with the Code 29 alarm.
    • You’re uncomfortable opening the battery compartment or using a multimeter.

    A technician can test the internal voltage regulator, charger module, and battery health with specialized equipment. They can also reprogram the generator’s settings if needed.

    Parts You May Need

    • Digital multimeter (to measure voltage)
    • Wire brush (to clean corroded terminals)
    • Battery cable terminals and connectors (if existing ones are damaged)
    • 12-volt deep-cycle battery (if one battery is failing)
    • Replacement charger or voltage regulator module (if the charging system is faulty)

    Quick Reference: Series vs. Parallel Wiring

    Parallel (Correct for 12V systems): Both batteries’ positive terminals are connected together, and both negative terminals are connected together. Voltage stays at 12 volts, but capacity (amp-hours) adds up.

    Series (Wrong for 12V systems): The positive of one battery connects to the negative of the other, then the remaining positive and negative go to the generator. Voltage doubles to 24 volts—this will trigger Code 29.

    Always check your owner’s manual for the correct wiring diagram for your specific model. When in doubt, take a photo of the current setup and have a technician verify it before you reconnect anything.

    Frequently Asked Questions

    Can I ignore Code 29 and keep running the generator?

    No. The alarm exists to prevent battery damage and potential electrical fires. Overcharging a battery can cause the electrolyte to boil, the case to crack, or the battery to explode in extreme cases. The generator will shut down automatically when it detects the fault, so you won’t have power anyway. Fix the root cause first.

    Why would my batteries be wired in series if that’s wrong?

    Sometimes a previous owner or technician made a mistake during installation or repair. Or, if you’ve recently replaced a battery, the new one might have been connected incorrectly. It’s also possible that the wiring was correct at first, but a loose connection caused someone to re-wire it incorrectly as a “fix.” Always verify against the manual.

    Is a boost-charge rate ever supposed to be on maximum?

    Boost charge is useful when the battery is deeply discharged and you want to charge it quickly. However, most Cummins Onan systems default to a moderate rate that’s safe for long-term use. If you’ve set it to maximum and never lowered it, that’s likely your culprit. Try a lower setting and monitor the battery voltage for a few charge cycles.

    What’s a safe battery voltage for my generator?

    A healthy 12-volt battery system should idle between 12.5 and 14.5 volts. When the generator is running and actively charging, it may climb to 14.5 to 15 volts briefly, but it should not exceed 16 volts during normal operation. Anything above 19 volts is a clear sign of overcharging and will trigger Code 29.

    Disclaimer: This article provides general information for educational purposes and is not a substitute for your generator’s owner’s manual or professional service. Always consult the manufacturer’s documentation for your specific model before attempting repairs. If you are unsure about any step, contact a qualified technician or your generator’s dealer. Improper battery handling or electrical work can result in injury, fire, or equipment damage.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Briggs & Stratton FC_2 Error: Low Oil Pressure

    The FC_2 fault code means your generator’s oil pressure has dropped below safe operating levels, and the engine has automatically shut down to prevent serious damage.

    Why This Matters

    When your Briggs & Stratton standby generator displays the FC_2 code, it’s telling you something critical: the engine isn’t getting enough oil pressure to keep its internal parts lubricated. This is a protective shutdown, not a minor warning. Bearings, pistons, and crankshafts depend on constant oil pressure to prevent metal-on-metal contact. Run an engine without adequate oil pressure for even a few minutes, and you’re looking at catastrophic internal damage—seized bearings, scored cylinder walls, and a repair bill that can exceed the cost of a new engine.

    The good news: most FC_2 faults are caused by something simple that you can diagnose and fix yourself in under an hour.

    Diagnostic Checklist

    1. Check the oil level first. This is the most common cause. Locate the oil dipstick on your engine (usually a yellow or orange handle on the side of the block). Pull it out, wipe it clean with a lint-free cloth, reinsert it fully, then pull it out again to read the level. The oil should reach the “full” mark. If it’s low, top it up with the correct grade—most Vanguard engines in Briggs & Stratton generators use 5W-30 synthetic oil. Do not overfill; overfull oil can also trigger pressure problems.
    2. Verify you’re using the right oil grade. Check your generator’s manual or the oil cap label for the manufacturer’s specification. Using the wrong viscosity (thickness) can cause pressure issues. Thinner oil flows too easily and doesn’t maintain pressure; thicker oil doesn’t flow enough, especially in cold weather.
    3. Inspect the oil filter. If your generator has an oil filter cartridge, it may be clogged. A dirty filter restricts oil flow and can trigger the pressure switch. Turn off and allow the engine to cool, then unscrew the filter (you may need an oil filter wrench). Examine it for debris or discoloration. If it looks dark or clogged, replace it with the manufacturer-specified part. If you’re not sure, replace it anyway—filters are inexpensive insurance.
    4. Check for oil leaks. Look around the base of the engine, under the valve cover, and along the oil pan seams. A slow leak can drop the oil level between uses. Wipe the suspected area dry, run the engine briefly (if it starts), then check again. Tighten any loose drain plugs or filter housings. If you find a leaking gasket or seal, note it for professional repair.
    5. Confirm the oil pressure switch isn’t stuck. The pressure switch is a small cylindrical component (usually with one or two electrical connectors) mounted on the engine block, often near the oil filter. A stuck or faulty switch can trigger the fault even when oil pressure is normal. If you’ve confirmed the oil level is correct and the filter is clean, the switch itself may need replacement. This is a straightforward part swap—disconnect the electrical connector, unscrew the old switch, and screw in a new one hand-tight, then snug with a wrench.
    6. Rule out internal engine wear. If the oil level is full, the filter is clean, and the switch is new, but the FC_2 code persists, the engine may have internal wear (worn bearings, scored cylinder walls, or a damaged oil pump). This requires professional inspection and likely engine overhaul or replacement.
    7. Reset the fault code. Once you’ve addressed the cause (added oil, replaced filter, or swapped the switch), turn off the generator, wait 30 seconds, and restart it. The code should clear if the underlying issue is resolved. If it returns immediately, the problem isn’t fixed yet.

    When to Call a Pro

    Contact a certified Briggs & Stratton technician if you encounter any of these:

    • The oil level is full, the filter is new, and the code persists. This suggests a faulty oil pressure switch or internal engine damage. A technician can test the switch with a multimeter and inspect the engine for wear.
    • You find a visible oil leak that you can’t tighten. Leaking gaskets, seals, or cracked castings require disassembly and replacement—not a DIY job for most homeowners.
    • The engine makes grinding or knocking sounds even after you’ve corrected the oil level. This indicates internal damage already in progress and requires immediate professional evaluation.
    • You’re uncomfortable working on the engine. Oil pressure switches and filters are straightforward, but if you’re unsure, it’s better to have a pro handle it than risk making things worse.

    Parts You May Need

    • Motor oil (5W-30 synthetic, or per your manual)
    • Oil filter cartridge (manufacturer-specific part number)
    • Oil pressure switch (if the original is faulty)
    • Oil filter wrench (if you don’t have one)
    • Lint-free cloth or paper towels

    Frequently Asked Questions

    Q: Can I run the generator if the FC_2 code appears but the engine seems fine?

    A: No. The FC_2 shutdown is a safety feature. Running the engine without adequate oil pressure will destroy internal bearings and the crankshaft in minutes, resulting in catastrophic failure. Always diagnose and fix the root cause before restarting.

    Q: What’s the difference between low oil level and a faulty oil pressure switch?

    A: Low oil level reduces the actual pressure in the engine, which the switch detects and reports. A faulty switch may trigger the fault even when oil pressure is normal. Start by checking the dipstick; if the level is full and the code persists after replacing the filter, the switch is likely the culprit.

    Q: How often should I check the oil in my standby generator?

    A: Check the oil level before each use or at least monthly during the heating season when your generator may run. Change the oil and filter annually or per the manufacturer’s maintenance schedule, whichever comes first. Regular maintenance prevents most FC_2 faults.

    Q: Can I use a different oil grade if I can’t find the recommended one?

    A: No. Always use the oil grade specified in your manual or on the oil cap. Using thinner oil (e.g., 0W-20 instead of 5W-30) will not maintain proper pressure; using thicker oil may restrict flow and also cause pressure problems. Stick to the manufacturer’s spec.

    Final Thoughts

    The FC_2 code is your generator’s way of protecting itself. Don’t ignore it or try to work around it. In most cases, the fix is straightforward: check and top up the oil, replace a dirty filter, or swap a faulty switch. These are all tasks a homeowner with basic tools can handle in an afternoon. If you’ve gone through the checklist and the code persists, that’s when you call in a professional. Either way, addressing the FC_2 fault promptly will keep your generator running reliably for years to come.

    Disclaimer: This article provides general troubleshooting guidance for Briggs & Stratton generators. Always consult your specific generator’s owner manual and follow the manufacturer’s instructions for maintenance, repair, and safety. If you are unsure about any procedure, contact a qualified technician. Improper repair can result in equipment damage or personal injury.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Briggs & Stratton FC_8 Error Code: Transfer Switch Fault Explained

    What does this code mean? The FC_8 error indicates your generator’s controller isn’t detecting the transfer switch’s position, signaling a communication or switch fault.

    The FC_8 error code on your Briggs & Stratton home standby generator points to a problem with the transfer switch system. Essentially, the generator’s controller expects a confirmation signal from the transfer switch about its current position—whether it’s connecting your home to utility power or generator power. When this confirmation doesn’t arrive, the controller flags an FC_8 fault.

    This can happen for several reasons, including a failed auxiliary contact inside the transfer switch, a damaged or loose communication wire between the generator and the automatic transfer switch (ATS), or a malfunctioning control relay. Because the transfer switch is a critical safety component that manages power flow between utility and generator sources, diagnosing and repairing this fault usually requires a professional electrician or authorized dealer.

    Diagnostic Checklist

    1. Visual Inspection: Check the transfer switch and generator for any obvious signs of damage, corrosion, or loose connections, especially around wiring terminals.
    2. Verify Wiring Connections: Ensure all communication wires between the generator and the ATS are securely attached and free from frays or breaks.
    3. Reset the Generator Controller: Power down the generator, wait a few minutes, then restart to see if the fault clears.
    4. Check for Auxiliary Contact Operation: If you have access and basic tools, gently test the auxiliary contacts on the transfer switch to confirm they move and make contact as expected.
    5. Inspect Control Relays: Listen for clicking sounds from relays during startup; absence might indicate relay failure.
    6. Review Transfer Switch Position: Confirm the transfer switch is not stuck between positions and is fully switching to either utility or generator power.
    7. Consult the Generator Display or Manual: Look for additional error messages or guidance specific to your model.
    8. Document Findings: Note any irregularities or damaged parts found during inspection to inform your technician.

    When to Call a Pro

    Because the transfer switch handles live electrical circuits, improper handling can be hazardous. Contact a qualified electrician or authorized Briggs & Stratton dealer if you notice any of the following:

    • Persistent FC_8 error after basic troubleshooting steps.
    • Burning smell, smoke, or visible damage near the transfer switch or wiring.
    • Generator fails to transfer power or switches erratically.
    • Loose or broken wires that you are uncomfortable repairing yourself.
    • Unfamiliarity with electrical safety precautions or tools.

    Parts You May Need

    • Replacement auxiliary contact for transfer switch
    • Control relay
    • Communication wiring (appropriate gauge and insulation)
    • Electrical connectors and terminal blocks
    • Basic electrical tools (multimeter, wire strippers)

    Frequently Asked Questions

    What is the transfer switch on a standby generator?

    The transfer switch is a device that safely switches your home’s electrical load between utility power and generator power, preventing backfeed and ensuring seamless power transfer during outages.

    Can I reset the FC_8 error code myself?

    You can try resetting the generator controller by powering it off and on, but if the error persists, professional diagnosis is recommended due to electrical safety concerns.

    Is it dangerous to ignore the FC_8 fault code?

    Yes, ignoring this fault can lead to unsafe power transfer conditions, risking damage to your generator, home wiring, or utility lines, and posing safety hazards.

    How much does it cost to fix a transfer switch fault?

    Costs vary depending on parts and labor; simple wiring repairs might be inexpensive, but replacing transfer switch components or relays can cost several hundred dollars. Always get a professional estimate.

    Disclaimer: This article provides general information about the FC_8 error code on Briggs & Stratton home standby generators. Always refer to your specific model’s manufacturer manual and follow safety guidelines. When in doubt, consult a licensed electrician or authorized service dealer.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Briggs & Stratton FC_7 Error Code: High Oil Temperature Explained

    What does this code mean? The FC_7 error code signals that your Briggs & Stratton home standby generator’s oil temperature has risen above safe limits, indicating potential overheating.

    When your Briggs & Stratton home standby generator displays the FC_7 error, it’s alerting you that the oil temperature sensor has detected a dangerously high oil temperature, typically above 300°F for air-cooled models. This is a critical warning because excessive oil temperature can lead to engine damage if not addressed promptly.

    What Causes High Oil Temperature?

    Several common issues can cause the oil temperature to rise beyond safe operating levels:

    • Restricted Airflow: Blocked intake louvers or debris inside the generator enclosure can reduce cooling airflow, causing the engine and oil to overheat.
    • Sustained Overload: Running the generator continuously at or above its rated capacity generates extra heat that can push oil temperature too high.
    • Low Oil Level: Insufficient oil means less lubrication and more friction inside the engine, which increases heat buildup.

    After this fault triggers, it’s important to let the generator cool completely before attempting to restart it to avoid further damage.

    Diagnostic Checklist

    1. Inspect Air Intake Louvers: Check for leaves, dirt, or debris blocking the air intake vents and clean them to ensure proper airflow.
    2. Clear Debris Inside Enclosure: Open the generator enclosure and remove any accumulated dirt, dust, or foreign objects that could restrict cooling.
    3. Check Oil Level: Use the dipstick to verify the oil level is within the recommended range; add oil if it’s low.
    4. Examine Oil Quality: Look for dark, dirty, or burnt-smelling oil, which may require an oil change.
    5. Reduce Load: Ensure the generator isn’t running above its rated wattage; unplug nonessential devices to lower the load.
    6. Allow Cooling Time: After shutdown due to FC_7, wait at least 30 minutes or until the unit is cool before restarting.
    7. Inspect Oil Temperature Sensor Wiring: Look for loose or damaged sensor connections that might cause false readings.
    8. Review Operating Environment: Confirm the generator is installed in a well-ventilated area away from heat sources.

    When to Call a Pro

    If you have tried the above steps and the FC_7 error persists, or if you notice any of the following, it’s time to contact a qualified technician:

    • The generator frequently shuts down with the FC_7 code despite normal airflow and oil levels.
    • Visible oil leaks or low oil pressure warnings accompany the high oil temperature error.
    • The oil temperature sensor or wiring appears damaged or corroded.
    • Unusual engine noises, smoke, or burning smells are present during operation.
    • The generator fails to restart after cooling down.

    Parts You May Need

    Frequently Asked Questions

    What should I do immediately if my generator shows the FC_7 code?

    Stop using the generator and allow it to cool down fully before attempting to restart. Check for airflow restrictions and oil level issues as initial troubleshooting steps.

    Can I keep running the generator if it shows high oil temperature?

    No. Continuing to run the generator with high oil temperature risks severe engine damage. Address the cause and let the unit cool before restarting.

    How often should I check the oil level to avoid FC_7 errors?

    It’s best to check oil levels before each use or at least monthly during regular operation to maintain proper lubrication and prevent overheating.

    Is cleaning the air intake enough to fix the high oil temperature issue?

    Cleaning the air intake can help if airflow restriction is the cause, but you should also verify oil levels, load conditions, and sensor integrity to fully resolve the issue.

    Disclaimer: This article provides general information about the FC_7 error code on Briggs & Stratton home standby generators. Always follow the specific instructions and safety guidelines in your manufacturer’s manual for your exact model.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.

  • Briggs & Stratton FC_6 Error Code: Engine Overspeed Explained

    What does this code mean? The FC_6 code signals that your generator’s engine is running faster than safe limits, which can cause serious damage if not fixed immediately.

    The FC_6 error code on Briggs & Stratton home standby generators indicates that the engine speed has exceeded its maximum safe operating RPM. This overspeed condition is critical because running the engine too fast can lead to severe mechanical failures or catastrophic damage.

    Common causes of this fault include a governor that is stuck in the open position, a broken or weakened governor spring, or in electronic fuel injection (EFI) models, a throttle actuator that is stuck. The governor’s job is to regulate engine speed by controlling fuel and air intake. When it fails, the engine can accelerate uncontrollably.

    Diagnostic Checklist

    1. Turn off the generator immediately. Operating under overspeed conditions risks major engine damage.
    2. Inspect the governor linkage. Look for any obvious signs of sticking, damage, or disconnection in the mechanical governor components.
    3. Check the governor spring. A broken or stretched spring can prevent proper speed regulation.
    4. For EFI models, examine the throttle actuator. Ensure it moves freely and isn’t stuck in a high-throttle position.
    5. Look for debris or corrosion. Dirt or rust can cause mechanical parts to stick or fail.
    6. Verify engine oil level and condition. Although not a direct cause, poor lubrication can contribute to erratic engine behavior.
    7. Inspect the air filter. A clogged air filter can affect engine performance and governor response.
    8. Consult the operator’s manual. Review any model-specific troubleshooting steps or warnings related to overspeed conditions.

    When to Call a Pro

    If you’ve checked the basics and the problem persists, or if you notice any of the following, it’s time to contact a qualified technician:

    • The engine continues to run at dangerously high speeds despite your attempts to fix the governor or throttle components.
    • Unusual noises or vibrations coming from the engine during startup or operation.
    • Visible damage to the governor mechanism or throttle actuator.
    • The generator shuts down unexpectedly or fails to start after the FC_6 code appears.
    • You are unsure about safely inspecting or repairing mechanical governor parts.

    Because overspeed can cause catastrophic engine failure, a professional assessment ensures the root cause is properly identified and repaired.

    Parts You May Need

    • Governor spring
    • Throttle actuator (for EFI models)
    • Governor linkage components
    • Air filter
    • Engine oil and oil filter
    • Basic hand tools (screwdrivers, wrenches)

    Frequently Asked Questions

    What causes the FC_6 engine overspeed error on Briggs & Stratton generators?

    It is typically caused by a stuck-open governor, a broken governor spring, or a stuck throttle actuator in EFI models, all of which prevent proper engine speed regulation.

    Can I keep using the generator if I see the FC_6 code?

    No. Continuing to operate the generator under overspeed conditions can cause severe engine damage. Shut it down immediately and troubleshoot before restarting.

    Is it safe for a homeowner to fix an overspeed issue?

    Some basic inspections like checking the governor linkage or spring can be done safely, but if you’re unsure or the problem persists, it’s best to call a professional technician.

    How can I prevent the FC_6 overspeed error from happening?

    Regular maintenance including cleaning, lubricating, and inspecting the governor and throttle components, as well as routine oil and air filter changes, can help prevent overspeed faults.

    Disclaimer: This article provides general information about the FC_6 error code on Briggs & Stratton home standby generators. Always follow the specific instructions and safety guidelines in your generator’s manufacturer manual.

    Source: Information adapted from official manufacturer documentation (reference). Always consult your generator owner’s manual for model-specific procedures.