2800
Auxiliary Shutdown
An emergency stop (E-stop) switch was activated or left in the OFF position.
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Generator troubleshooting
Troubleshooting Hub
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Shutdown / Critical
Shutdown and urgent alarm articles
2800 / 2801
E-Stop / Auxiliary Shutdown
Emergency stop or front-panel AUX shutdown rocker was activated.
2400
Fuse Problem
A blown fuse detected on the control board. Identify the cause before replacing.
1400
High Coolant Temperature
Coolant exceeded 246°F. Check coolant level and radiator airflow.
3700 / 3701
High Coolant Temperature
Engine coolant too hot. Check coolant level, radiator, thermostat, and fan.
2725 / 2735
High Oil Temp / Low Oil Level
Oil temperature exceeded 320°F or oil level below minimum.
1400 / 1401
High Temperature
Engine has overheated. Check airflow clearances, oil level, and air filter.
LOCKEDROTOR
Kohler Locked Rotor Alarm
Locked Rotor — Shutdown Alarm The Locked Rotor alarm means the controller sent a start command but detected no engine rotation within the preset time window (typically 2–3 seconds). To protect the starter motor from damage, the controller halts all crank attempts and locks out the unit until the fault is cleared. Despite the alarming name, the engine itself is often not physically seized — the most common cause is a weak or dead battery or a failed speed sensor. Dead or weak 12V battery (most common — 90% of cases) Failed magnetic pickup / speed sensor (no rotation signal) Faulty or stuck starter motor or solenoid Loose, corroded, or unseated wiring harness connectors Physically seized engine (debris, corrosion, extended storage) Worn or misaligned brushes / slip rings (generator end) Faulty controller / outdated controller firmware Faulty battery charger — not maintaining battery charge
2720
Low Coolant Level
Coolant level sensor active for 5+ seconds. Check reservoir and inspect for leaks.
2720
Low Coolant Level
Coolant below the safe operating level. Liquid-cooled generators only.
2680 / 2681 / 2690
Low Fuel / Low Fuel Pressure
Fuel at 20% (warning), 10% (shutdown), or gas pressure below 5.2 in H₂O.
1300
Low Oil Pressure
Oil pressure dropped below the safe operating threshold. Check oil level and sensor.
1300 / 1301
Low Oil Pressure
Oil pressure below safe threshold. Check oil level immediately.
1100
Overcrank
Engine failed to start after all programmed crank attempts.
1100 / 1101
Overcrank
Engine failed to start after multiple crank attempts. Usually fuel pressure, air in lines, or weak battery.
2100 / 2101 / 2111 / 2112
Overload
Output current exceeded rated capacity. Shed loads or check for short circuit.
2100 / 2102
Overload
Too many appliances running. Generator exceeded its rated capacity.
1200 / 1205 / 1208
Overspeed
Engine exceeded 72 Hz (prolonged) or 75 Hz (instantaneous). Check governor wiring.
1200 / 1201
Overspeed
Engine speed exceeded the safe operating limit. Usually a governor failure or linkage issue.
1800 / 1801
Overvoltage
Output voltage more than 10% above nominal. AVR or wiring fault.
1501 / 1505
RPM Sense Loss
Controller cannot detect engine rotation. Weak battery, speed sensor, or ignition coil fault.
1521 / 1522 / 1523 / 1524
RPM Sensor Loss
Speed sensing signal lost during cranking or operation. Battery or MPU sensor.
1600 / 1603
Underspeed
Engine speed dropped below threshold. Likely overload or fuel delivery issue.
1600
Underspeed / Overloaded
RPM below 83.3% of target for 30 seconds. Overload or fuel issue.
1900 / 1901 / 1902 / 1906 / 1907
Undervoltage
Output voltage below 80% of nominal. Overload, AVR, brushes, or DPE wiring.
1900 / 1902
Undervoltage
Generator output voltage too low. Faulty AVR, overload, or worn brushes/slip rings.
Warning / Monitor
Monitor and maintenance articles
2750 / 2751 / 2760
Battery Warning / Very Low Battery
2751 is a SHUTDOWN alarm unique to PZ410 (battery below 9.0V). Act before it shuts down.
2770
Charger Warning
Built-in battery charger is failing or not receiving power. Battery will drain.
2770 / 2780
Charger Warning / Missing AC
Battery charger fault or no AC input. Battery will drain if unaddressed.
2750
Low Battery
Battery voltage below 12.1V for 60+ seconds. Act now before it causes a shutdown.
SVC A / SVC B
Service Schedule Due
Generator has reached a maintenance interval. Schedule service to maintain warranty.
SVC A / SVC B / Battery Maint
Service Schedule Due
PZ410 has reached a maintenance interval. Schedule service to maintain warranty.
Dealer / Service Required
Professional service required
Sensor Faults · ECU · Controller · Governor · Transfer Switch · Ignition Coils
IASD-Required Alarm Reference
Complete reference table of all PZ410 codes requiring Generac-authorized dealer service. Includes 40+ fault codes with descriptions and actions.
