Kohler Standby Generators Error Codes

Air Filter Restriction

Controller displays “Air Filter” or “Restricted Air Filter”; engine may run rich or lack power.

Intake Air Restriction Detected

Charger Failure

Controller displays “Battery Charger Failure” or similar alarm; battery voltage slowly drops over days.

Battery Charger Output Failure

Emergency Stop

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

Emergency Stop Circuit Activated

Ground Fault

Controller displays “Ground Fault” or “Earth Fault”; generator may trip off-line.

Ground Fault Detection Trip

High Battery Voltage

Controller displays “High Battery Voltage” or “Battery Overvoltage”; battery may feel warm or venting.

Battery Overcharging Condition

High Coolant Temperature

Controller displays “High Coolant Temp” on liquid-cooled models; generator shuts down under load.

Coolant Overtemperature Shutdown

High Engine Temperature

Controller displays “High Engine Temp” or “Overtemperature”; generator shuts down during operation.

Engine Overheat Shutdown

Loss of Phase

On three-phase Kohler standby generators, controller displays “Loss of Phase” or “Phase Failure”; some loads lose power.

Missing or Low Voltage on One or More Phases

Loss of Sensing

Controller displays “Loss of Sensing” or “Voltage Sense Loss”; generator may run but not transfer load.

Controller Voltage Sensing Circuit Failure

Low Battery Voltage

Controller displays “Low Battery Voltage” or “Low Battery”; generator may fail to crank or cranks slowly.

Starting Battery Under-Voltage Condition

Low Coolant Level

Liquid-cooled Kohler standby generator shuts down and displays “Low Coolant Level” or coolant level alarm.

Engine Coolant Level Protection Trip

Low Coolant Temperature

Controller displays “Low Coolant Temp” on liquid-cooled models; may inhibit automatic transfer under load.

Coolant Temperature Below Minimum for Load Acceptance

Low Cranking Speed

Controller displays “Low Cranking Speed” or similar; engine turns slowly and fails to start.

Starter Cranking RPM Below Threshold

Low Engine Temperature

Controller displays “Low Engine Temp” or “Engine Not Warmed Up”; unit may not transfer load or may run longer in exercise mode.

Engine Coolant Temperature Below Minimum Threshold

Low Fuel Pressure

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

Gaseous Fuel Supply Pressure Fault

Low Oil Level

Some Kohler models display “Low Oil Level” separate from pressure; generator may not start or may shut down.

Engine Oil Level Sensor Trip

Low Oil Pressure

Generator shuts down shortly after start and controller displays “Low Oil Pressure” fault.

Engine Low Oil Pressure Shutdown

Overcrank

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

Failed Engine Start / Overcrank Lockout

Overfrequency

Controller displays “Overfrequency” and may shut down or drop load; measured frequency is above 63 Hz on a 60 Hz unit.

Engine Overspeed / High Frequency Condition

Overload

Controller displays “Overload” or “Overcurrent”; main breaker trips when large loads start on generator power.

Generator Overcurrent / Overload Trip

Overspeed

Controller displays “Overspeed” and shuts the engine down quickly after start; may be accompanied by high frequency readings.

Engine Overspeed Protection Trip

Overvoltage

Controller displays “Overvoltage” and opens the main line circuit breaker; generator stops supplying power.

Generator Output Overvoltage Protection Trip

Service Required

Controller displays “Service Required” or “Maintenance Reminder”; generator still operates normally.

Scheduled Maintenance Interval Reached

Service Soon

Controller displays “Service Soon” or similar pre-maintenance warning; generator operates normally.

Upcoming Maintenance Interval Warning

Underfrequency

Controller displays “Underfrequency” or “Low Frequency”; lights flicker and motors sound sluggish when on generator power.

Engine Underspeed / Low Frequency Condition

Underspeed

Controller displays “Underspeed” shortly after start; engine may stall or run roughly at low RPM.

Engine Speed Below Minimum Threshold

Undervoltage

Controller displays “Undervoltage” or “Low Voltage” and drops the load; lights dim or equipment resets when generator runs.

Generator Output Undervoltage Condition

Symptom

Controller display is blank or unreadable; generator otherwise appears intact

Controller Power / Display Failure

Symptom

Coolant puddle under generator or sweet smell around unit

Coolant Leak

Symptom

Corrosion, rust, or rodent damage inside generator enclosure

Environmental / Pest Damage

Symptom

Fuel smell around generator or visible gas leak

Fuel Leak / Gas Odor

Symptom

Generator cranks but never fires (no attempt to start)

No-Start / No-Ignition Condition

Symptom

Generator enclosure vibrates excessively or walks on its pad during operation

Excessive Vibration

Symptom

Generator is excessively loud or has new knocking/metallic noises

Abnormal Mechanical Noise

Symptom

Generator runs but does not transfer power to the house

Automatic Transfer Switch (ATS) Fails to Transfer Load

Symptom

Generator runs its weekly exercise but never transfers load during real outages

Exercise-Only Operation / No Load Transfer

Symptom

Generator starts and transfers, then drops out and utility power returns repeatedly

Intermittent Transfer / Nuisance Drop-Out

Symptom

Generator starts but runs rough, surges, or hunts at no load

Unstable Engine Operation / Surging

Symptom

Generator will not start at all (no crank, no click) when utility fails

No-Start / No-Crank Condition

Symptom

Oil leaking under generator or oil spots on pad

Engine Oil Leak

Symptom

Strong exhaust smell or fumes inside the house when generator runs

Exhaust Fume Intrusion