The Komatsu PC55 is a compact hydraulic excavator widely used for construction, landscaping, and utility work. Its instrument cluster provides vital status information and warnings to help operators maintain optimal performance and safety on the jobsite.
Komatsu PC55 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | A major fault has been detected by the PC55's monitoring system, which could quickly lead to equipment damage or unsafe operation. | Shut down the engine immediately and investigate the warning source. | |
| Master Caution | AMBER | A non-critical issue has been recognized by the PC55, such as a sensor irregularity or minor malfunction. | Check the display for further details and address the cause soon. | |
| Check Engine (MIL) | AMBER | The PC55's engine control unit has detected an engine-related fault or abnormality. | Inspect engine codes and schedule service if needed. | |
| Engine Oil Pressure | RED | Engine oil pressure on the PC55 has dropped below safe operating levels, risking severe engine damage. | Stop the machine at once and check oil level and leaks. | |
| Battery / Charging | RED | The charging system on the PC55 is not working, and the battery is not being replenished. | Inspect the alternator, connections, and battery condition. | |
| Coolant Temperature | RED | The engine coolant temperature has exceeded the safe range on the PC55, risking overheating. | Stop operation to let the engine cool and check coolant level. | |
| Low Fuel | AMBER | Fuel in the PC55's tank is nearly depleted, and running out may cause engine stalling. | Refuel as soon as possible. | |
| Hydraulic System | AMBER | A fault has been detected in the PC55's hydraulic system, such as low fluid or filter restriction. | Inspect hydraulic oil level and check for leaks or clogged filters. | |
| Hydraulic Oil | AMBER | Hydraulic oil temperature or level is abnormal in the PC55, which may affect machine performance. | Check oil level and top up or replace as required. | |
| Fuel Filter / Water Separator | AMBER | The PC55 detects water accumulation or blockage in the fuel filter assembly. | Drain water and replace the fuel filter if needed. | |
| Air Filter | AMBER | The air filter on the PC55 is clogged or restricted, reducing engine efficiency. | Clean or replace the air filter promptly. | |
| DPF / Regeneration | AMBER | The diesel particulate filter on the PC55 requires regeneration due to soot accumulation. | Initiate or complete regeneration as instructed in the operator’s manual. | |
| DEF / AdBlue | AMBER | DEF (AdBlue) level is low in the PC55, risking emission system faults. | Refill the DEF tank soon. | |
| Water in Fuel | AMBER | Water has been detected in the PC55’s fuel separator, which could harm the injection system. | Drain the water separator immediately. | |
| Work Lights | BLUE | The PC55's work lights are switched on, improving visibility for night or low-light tasks. | No action needed unless lights are not required. | |
| Beacon / Rotating Light | AMBER | The beacon is active on the PC55, signaling presence to others on the worksite. | Use as required for site safety. | |
| Service / Hour Meter | AMBER | The PC55 is due for scheduled maintenance based on engine hours. | Perform routine service per the maintenance schedule. | |
| Parking Brake | RED | The PC55's parking brake is engaged, preventing travel or swing operations. | Release the parking brake before moving the machine. | |
| Swing / Slew Lock | AMBER | The swing lock is engaged on the PC55, restricting upper structure rotation. | Disengage the swing lock if rotation is needed. |
19 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
Immediately stop the PC55, check oil level and refill if low; if the warning persists, inspect for leaks, and consult a Komatsu technician for further diagnosis.
Coolant Temperature Warning
Common causes
- Coolant loss or low level
- Radiator or fan malfunction
- Thermostat stuck closed
What to do
Turn off the engine to allow cooling, check coolant level and radiator for obstructions, and repair any leaks or faulty components before resuming operation.
Battery / Charging Warning
Common causes
- Alternator failure
- Loose or corroded battery terminals
- Broken drive belt
What to do
Inspect the alternator, belt, and battery connections on the PC55; replace or repair defective parts to restore proper charging.
Hydraulic System Warning
Common causes
- Low hydraulic oil
- Hydraulic filter blockage
- Hydraulic leak
What to do
Check and top up hydraulic oil, replace filters if clogged, and inspect hoses and fittings for leaks on the PC55.
DPF / Regeneration Warning
Common causes
- Incomplete regeneration cycles
- Excessive idling
- DEF system faults
What to do
Follow the PC55's regeneration procedure as outlined in the manual; if warning persists, contact a Komatsu dealer for diagnostic support.
Frequently Asked Questions
What should I do if the master warning light appears on my PC55?
Stop the machine immediately, check the display for specific fault codes, and do not restart until the cause is identified and corrected.
How do I perform a DPF regeneration on the Komatsu PC55?
Follow the instructions in the operator’s manual; typically, park the machine, set engine speed as directed, and initiate regeneration via the display panel.
Why does the low fuel warning come on even though there is fuel in the tank?
The PC55's sensor may detect a low level due to machine angle or a sticking float; check fuel level physically and refill as needed.
How often should I service the hydraulic filter on the PC55?
Refer to the maintenance schedule in the operator's manual, but generally inspect and replace the hydraulic filter every 500 operating hours or sooner if indicated.
Can I continue working if the air filter warning is on?
It is best to clean or replace the air filter as soon as possible to avoid reduced engine performance or potential damage.