The Komatsu PC300 is a robust hydraulic excavator widely used for heavy-duty earthmoving and construction applications. Its operator panel features a range of indicator and warning lights to monitor vital systems and ensure safe, efficient operation in demanding environments.
Komatsu PC300 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | A major failure has been detected in a critical system of the PC300, such as hydraulic, engine, or electrical components. | Safely stop the excavator immediately and investigate the fault shown in the display. | |
| Master Caution | AMBER | A cautionary issue like low fluid or abnormal sensor reading has occurred, but the PC300 can still operate temporarily. | Check the information panel for details and address the indicated problem soon. | |
| Check Engine (MIL) | AMBER | The engine control unit has detected an issue affecting performance or emissions in the PC300's engine. | Inspect engine codes via the monitor and arrange for service if the light stays on. | |
| Engine Oil Pressure | RED | The PC300's engine oil pressure has dropped below safe levels, risking severe engine damage. | Shut down the engine at once and check oil level and for leaks. | |
| Battery / Charging | RED | The charging system is not supplying power, so the PC300's battery is discharging. | Stop the machine and inspect alternator, belts, and battery connections. | |
| Coolant Temperature | RED | Engine coolant temperature in the PC300 has exceeded the safe operating range. | Turn off the excavator and allow the engine to cool before checking coolant level. | |
| Transmission Temp | AMBER | Transmission oil temperature is higher than normal, which can lead to component wear in the PC300. | Pause work and let the machine idle to cool; check oil level if warning persists. | |
| Brake System | RED | A malfunction in the PC300's braking system has been detected, compromising stopping ability. | Immediately stop operation and inspect brake components or call for service. | |
| Parking Brake | RED | The parking brake is engaged on the PC300, preventing travel. | Release the parking brake before attempting to move the excavator. | |
| Hydraulic System | AMBER | Hydraulic system pressure or temperature is outside the recommended range on the PC300. | Inspect hydraulic fluid level and filters; pause operation if issue remains. | |
| Hydraulic Oil | AMBER | Hydraulic oil level or condition is below optimal for the PC300's system. | Check for leaks and refill or change hydraulic oil as needed. | |
| Engine Oil Temperature | AMBER | Engine oil temperature is elevated, which may affect lubrication in the PC300. | Allow the engine to idle and cool, then inspect oil quality and level. | |
| Air Filter | AMBER | The air filter in the PC300 is clogged or restricted, reducing engine efficiency. | Clean or replace the air filter to maintain proper airflow. | |
| Fuel Filter / Water Separator | AMBER | The fuel filter or water separator requires attention, possibly due to clogging or excess water in the PC300. | Drain water and replace the fuel filter as soon as possible. | |
| Low Fuel | AMBER | The PC300's fuel tank is reaching a low level and needs refueling soon. | Plan to refuel at the next safe opportunity. | |
| DPF / Regeneration | AMBER | The diesel particulate filter on the PC300 requires regeneration to burn off soot. | Initiate or allow automatic DPF regeneration as per operator's manual. | |
| DEF / AdBlue | AMBER | The DEF/AdBlue level is low, impacting the PC300's emission control system. | Refill the DEF/AdBlue tank to avoid reduced engine performance. | |
| Water in Fuel | AMBER | Water has accumulated in the PC300's fuel system, risking injector or pump damage. | Drain the water separator immediately to avoid engine issues. | |
| Service / Hour Meter | AMBER | Scheduled maintenance is due based on the PC300's operating hours. | Arrange for the recommended service tasks at the next break. | |
| Work Lights | BLUE | The PC300's work lights are switched on for increased visibility. | No action needed unless lights are not required. | |
| Beacon / Rotating Light | AMBER | The safety beacon is active, indicating the PC300 is in operation. | Turn off the beacon when not needed for site safety. | |
| Swing / Slew Lock | AMBER | The swing lock is engaged, preventing the PC300's upper structure from rotating. | Disengage the swing lock before attempting to rotate the cab. | |
| Overload / Capacity | RED | The PC300 has exceeded its safe lifting capacity, risking tip-over or structural damage. | Immediately lower the load and reduce weight to within rated limits. | |
| Door Open | AMBER | The cab door on the PC300 is not fully closed, which can affect safety. | Securely close the door before resuming operation. | |
| High Exhaust Temp (HEST) | AMBER | Exhaust temperature is elevated during DPF regeneration on the PC300. | Keep clear of exhaust outlet and avoid parking near combustibles. |
25 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Engine Oil Pressure Warning
Common causes
- Low engine oil level
- Oil pump failure
- Oil filter blockage
What to do
Shut down the PC300 immediately, check the engine oil level and condition, and inspect for leaks or faulty oil pump. Do not restart until the root cause is resolved.
Hydraulic System Warning
Common causes
- Low hydraulic oil level
- Hydraulic filter clogging
- Hydraulic pump malfunction
What to do
Stop machine operation, inspect hydraulic fluid level and filters, and look for leaks or pump problems. Only resume work after correcting the issue.
Overload Warning
Common causes
- Lifting load beyond rated capacity
- Incorrect attachment use
- Unstable ground conditions
What to do
Lower the load right away, verify the attachment is correct for the task, and check ground stability. Never exceed the PC300's rated lift limits.
Coolant Temperature Warning
Common causes
- Insufficient coolant
- Radiator blockage
- Cooling fan malfunction
What to do
Safely stop the engine, let it cool, then check coolant level and inspect for radiator clogs or a faulty fan. Top up coolant and clean or repair as needed before restarting.
Battery / Charging Warning
Common causes
- Alternator failure
- Loose or corroded battery terminals
- Drive belt breakage
What to do
Turn off the PC300, examine the alternator and belt, and clean or tighten battery connections. Replace faulty parts before returning to service.
Frequently Asked Questions
What should I do if the DPF regeneration light stays on in my PC300?
Allow the machine to complete its automatic regeneration cycle, or follow the manual regeneration procedure in the operator's manual if the light does not go off.
Can I keep working if the hydraulic oil light is amber but not red?
You may continue briefly, but check the hydraulic oil level and condition as soon as possible to prevent further issues.
Why does the swing lock indicator stay lit even after disengaging?
There may be a sensor issue, or the swing lock may not be fully released; inspect the lock mechanism and consult service if needed.
How often should I reset the service/hour meter warning?
Reset the service indicator only after completing all required maintenance at the specified hour interval for the PC300.
What does it mean if the DEF light flashes on my PC300?
A flashing DEF/AdBlue light means the fluid level is critically low or there is a system fault; refill the tank and check for leaks right away.