Komatsu SK815 Warning Light Symbols and What They Mean

The Komatsu SK815 skid steer loader features a digital instrument cluster monitoring the SAA4D95 engine, load-sensing hydraulics, and Powertrain. Warning lights alert the operator to system faults, maintenance needs, or safe operation status.

How to read the colors: Red indicates a critical fault that requires immediate shutdown; amber signals a caution or service need; green or blue denotes an active function or normal status.

Komatsu SK815 Warning Light Symbols

SymbolNameColorWhat it meansWhat to do
Master Warning (Stop)REDA serious fault has been detected; stop the engine immediately to prevent damage.Shut down the engine and consult the display for the specific fault code.
Master CautionAMBEROne or more non-critical warnings are active; check the message area for details.Review the display and address the indicated issue before continuing operation.
Check Engine (MIL)AMBERThe engine control unit has detected a malfunction in the emission or fuel system.Inspect the engine and fuel system; if sustained, contact your Komatsu dealer.
Engine Oil PressureREDEngine oil pressure is below safe level, risking severe engine damage.Stop the engine immediately and check oil level and for leaks.
Battery / ChargingREDThe charging system voltage is too low or the alternator is not charging the battery.Check alternator belt tension and wiring; run engine at high idle to test charging.
Coolant TemperatureREDEngine coolant temperature has exceeded the safe operating limit.Reduce load and idle engine to cool; inspect radiator and coolant level.
Hydraulic SystemAMBERHydraulic oil temperature is high or the filter is restricted, reducing performance.Allow hydraulics to cool; check oil level and replace filter if needed.
PParking BrakeREDThe parking brake is engaged or a fault is preventing release.Ensure parking brake is fully disengaged before moving; if light stays on, inspect switch.
Seat BeltREDThe operator's seat belt is not fastened or the buckle sensor is faulty.Fasten your seat belt; if light persists, check the buckle connection.
Glow Plug / PreheatAMBERThe glow plugs are heating to aid cold starting; wait for the light to turn off.Do not attempt to start until the glow plug light goes out (typically 5-10 seconds).
Low FuelAMBERFuel level is low; you have approximately 10-15 minutes of operation remaining.Refuel with clean diesel to avoid air ingress in the fuel system.
Water in FuelAMBERWater has been detected in the fuel/water separator; drain immediately.Open the drain valve at the bottom of the fuel filter to remove water.
Air FilterAMBERThe engine air filter is restricted, causing reduced engine power and efficiency.Clean or replace the air filter element to restore airflow.
Service / Hour MeterGREENDisplays total operating hours for planning maintenance intervals.Record the hours and schedule oil/filter changes per the owner's manual.
Work LightsGREENThe auxiliary work lights (LED) are turned on and illuminating the work area.Use only when necessary to conserve battery; turn off when leaving the machine.

15 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.

Most Important Warning Lights

Engine Overheating

Common causes

  • Low coolant level
  • Clogged radiator fins with debris
  • Faulty fan clutch or belt

What to do

Stop the engine and let it cool. Clean the radiator core with compressed air, top off coolant, and inspect the fan belt tension. If persistent, check the water pump.

Hydraulic System Failure

Common causes

  • Hydraulic oil low
  • Contaminated or restricted suction filter
  • Pump cavitation due to aeration

What to do

Park the machine safely, lower the boom and bucket, and check the hydraulic oil level in the sight glass. Replace the return and suction filters if dirty.

Charging System Fault

Common causes

  • Loose or damaged alternator belt
  • Corroded battery terminals
  • Failed alternator regulator

What to do

Check the belt tension (should deflect about 1/2 inch) and clean battery connections. If the battery light stays on, have the alternator tested.

Fuel System Contamination

Common causes

  • Water in fuel from condensation
  • Dirty fuel from storage tanks
  • Plugged fuel filter

What to do

Drain the water separator at the filter housing. Replace the fuel filter element and prime the system using the hand primer pump until firm.

Air Filter Restriction

Common causes

  • Dusty operating environment
  • Saturated filter element
  • Loose air intake hose connection

What to do

Remove the outer air filter element and tap it gently to dislodge dirt. Replace if heavily soiled or if the filter minder shows red. Ensure all clamps are tight.

Frequently Asked Questions

Why does my SK815 engine crank but not start?

Check the glow plug preheat cycle (wait for the amber light to extinguish). Ensure the fuel shutoff solenoid is engaging (listen for a click). If still no start, check for air in the fuel system or a faulty fuel lift pump.

What does the Master Caution light mean when I'm operating?

The Master Caution illuminates for issues like high hydraulic oil temperature, a clogged air filter, or a transmission fault. Press the INFO button on the dash to scroll through the active warnings on the display.

How often should I change the hydraulic oil in the SK815?

Komatsu recommends changing the hydraulic oil every 2000 hours or 2 years, whichever comes first. Also replace both the return and suction filters at the same time to maintain system cleanliness.

The bucket will not lift or curl properly—what could be wrong?

First check the hydraulic oil level (cold dipstick should read between marks). Next, inspect the control lockout lever to ensure it is fully released. If the problem persists, a faulty pump relief valve or cylinder seal may be the cause.

My SK815 suddenly lost power and the check engine light is on—what should I do?

This often indicates a clogged fuel filter or a malfunction in the electronic engine controls. Try changing the fuel filter and priming the system. If the light remains, have the diagnostic codes read by a Komatsu dealer.

How do I reset the service reminder light on the dash?

Turn the key to the ON position (engine off). Press and hold the HOUR button on the gauge cluster for 5 seconds until the service icon flashes, then release. The reminder will reset for the next interval.