Eaton Standby Generators Error Codes

Battery Charger Failure

Controller displays “Battery Charger Failure” or “Charger Fault”; battery voltage slowly drops over days and unit may not start.

Onboard Battery Charger Module Not Maintaining Charge

Control Board Failure

Controller displays “Control Board Failure”, “Internal Fault”, or is completely blank/unresponsive while battery voltage is normal.

Generator Control PCB Malfunction

Emergency Stop Active

Controller displays “Emergency Stop” or “E-Stop Active”; generator will not start.

Emergency Stop Circuit Open

Exercise Timer Fault

Controller displays “Exercise Fault” or scheduled exercise runs do not occur on Eaton standby generator.

Controller Exercise Schedule Configuration or RTC Failure

Ground Fault

Controller displays “Ground Fault” or “Earth Fault” and trips the generator output.

Unintended Current Path to Ground on Output Circuit

High Coolant Temperature

Liquid-cooled Eaton generator displays “High Coolant Temp” and shuts down under load.

Liquid-Cooled Engine Overheating

High Engine Temperature

Controller displays “High Engine Temp” or “Overcrank – High Temp” and shuts down the generator during or shortly after running.

Engine Overheating Protection Trip

High Fuel Pressure

Controller displays “High Fuel Pressure” or fuel system fault; engine may run rough or surge.

Excessive Gas Pressure at Engine Regulator

Low Battery

Controller displays “Low Battery” and generator will not crank or cranks very slowly, especially in cold weather.

Battery Voltage Below Cranking Threshold

Low Coolant Level

On liquid-cooled Eaton standby generators, controller displays “Low Coolant Level” and prevents start or shuts down.

Engine Coolant Level Below Sensor Threshold

Low Fuel Pressure

Controller displays “Low Fuel Pressure” or “Fuel Supply Fault”; engine may start then stall or fail to start.

Insufficient Gas Pressure at Engine Regulator

Low Oil Level

Controller displays “Low Oil Level” or similar message and prevents the generator from starting.

Crankcase Oil Level Below Float Switch Threshold

Low Oil Pressure

Controller displays “Low Oil Pressure” and shuts down the generator shortly after start or prevents start.

Engine Lubrication Pressure Loss

Overcrank

Controller displays “Overcrank” after multiple failed start attempts; engine cranks but does not start.

Failed Engine Start After Maximum Crank Attempts

Overfrequency

Controller displays “Overfrequency” or “High Hz” and may shut down the generator or prevent transfer.

Engine Speed Above Rated Frequency

Overspeed

Controller displays “Overspeed” and shuts down the generator shortly after start; engine sounds unusually fast before shutdown.

Engine Speed Above Safe Limit

Overvoltage

Controller displays “Overvoltage” and shuts down the generator; measured output voltage is significantly above nominal (e.g., >260 V on 240 V system).

Generator Output Voltage Regulation Failure – High

Phase Imbalance

Controller displays “Phase Imbalance” or “Voltage Imbalance” on three-phase Eaton standby generators.

Unequal Line Voltages Between Phases

Reverse Power / Backfeed Detected

Controller displays “Reverse Power” or similar; generator trips offline when abnormal power flow is detected.

Power Flow From Utility Toward Generator

Sensor Failure

Controller displays “Sensor Failure”, “Analog Input Fault”, or specific sensor error; readings show impossible values.

Failed Engine or Generator Monitoring Sensor

Starter Fault

Controller displays “Starter Fault” or “Crank Fault”; engine does not crank when a start is commanded.

Starter Motor or Cranking Circuit Failure

Underfrequency

Controller displays “Underfrequency” or “Low Hz” and may prevent transfer or drop load; lights may dim when large loads start.

Engine Speed Below Rated Frequency

Undervoltage

Controller displays “Undervoltage” or “Low Voltage” and either prevents transfer or shuts down the generator.

Generator Output Voltage Regulation Failure – Low

Symptom

Controller display is blank or very dim, but battery is known to be good.

Controller Power Supply or Display Failure

Symptom

Corrosion on battery terminals and metal parts inside the generator enclosure.

Electrolytic Corrosion / Environmental Degradation

Symptom

Generator cranks but never starts; no error code displayed, or only generic “Failed to Start”.

No Ignition or No Fuel Combustion

Symptom

Generator is excessively loud or has new knocking/metallic noises during operation.

Abnormal Mechanical Noise / Possible Engine or Mount Failure

Symptom

Generator runs but does not transfer load to the house during an outage.

Automatic Transfer Switch Fails to Transfer

Symptom

Generator runs but produces no AC output voltage.

Loss of Excitation or Open Output Circuit

Symptom

Generator starts and stops repeatedly during an outage, cycling on and off.

Unstable Run Command or Fault-Induced Cycling

Symptom

Generator starts and transfers, but then drops load and shuts down after a few minutes.

Thermal or Electrical Protection Trip Under Load

Symptom

Generator vibrates excessively during operation, causing rattling noises or movement.

Excessive Vibration / Imbalance

Symptom

Generator will not crank at all; no clicking sound from starter when start is commanded.

Start Signal or Power Delivery Failure

Symptom

Lights flicker or dim noticeably when large loads start while on generator power.

Transient Voltage Sag / Load Step Response

Symptom

Oil leaking under the generator or visible oil on the engine surfaces.

Engine Lubrication System Leak

Symptom

Strong fuel gas smell around the generator, especially during or after operation.

Gas Leak in Fuel Supply System

Symptom

Water or moisture accumulation inside the generator enclosure.

Enclosure Water Ingress