The Komatsu PC138 is a mid-size hydraulic excavator designed for urban and tight job sites, offering excellent maneuverability and operator comfort. Its instrument cluster provides crucial real-time alerts to ensure safe and efficient operation of the machine.
Komatsu PC138 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | A severe malfunction or safety issue has been detected in the PC138, such as catastrophic engine or hydraulic failure. | Shut down the machine immediately and investigate the root cause before restarting. | |
| Master Caution | AMBER | A non-critical fault has occurred in the PC138 that requires attention but does not mandate immediate shutdown. | Safely stop and review the monitor for details; schedule repairs as soon as possible. | |
| Check Engine (MIL) | AMBER | The engine control system has detected an abnormality in the PC138's electronic management. | Inspect engine diagnostics on the monitor and address error codes promptly. | |
| Engine Oil Pressure | RED | Engine oil pressure has dropped below safe levels, risking severe engine damage in the PC138. | Stop the engine immediately and check oil level and condition. | |
| Battery / Charging | RED | The alternator is not charging the battery, risking electrical system failure in the PC138. | Inspect the charging system and battery connections before resuming operation. | |
| Coolant Temperature | RED | Engine coolant temperature is excessively high, indicating potential overheating in the PC138. | Shut down the engine and allow it to cool; check coolant level and radiator. | |
| Hydraulic System | AMBER | A hydraulic system fault or abnormal pressure has been detected in the PC138. | Inspect for leaks or abnormal noises and check fluid level. | |
| Hydraulic Oil | AMBER | Hydraulic oil level or temperature is outside the normal range on the PC138. | Check hydraulic oil reservoir and top up or cool down as needed. | |
| Low Fuel | AMBER | Remaining fuel is low, and the PC138 may soon run out if not refueled. | Refuel at the next safe opportunity. | |
| DPF / Regeneration | AMBER | Diesel particulate filter requires regeneration due to soot accumulation in the PC138. | Initiate regeneration process as instructed in the operator manual. | |
| DEF / AdBlue | AMBER | DEF (AdBlue) level is low or there is a fault in the SCR system on the PC138. | Refill DEF tank and inspect for possible SCR system errors. | |
| Water in Fuel | AMBER | Water has been detected in the fuel filter, risking injector or pump damage in the PC138. | Drain the water separator promptly to prevent engine issues. | |
| Fuel Filter / Water Separator | AMBER | The fuel filter is clogged or the water separator is full on the PC138. | Replace the filter and empty the separator to maintain fuel system health. | |
| Air Filter | AMBER | The air filter is restricted, reducing engine performance in the PC138. | Inspect and clean or replace the air filter as necessary. | |
| Engine Oil Temperature | AMBER | Engine oil temperature is higher than recommended for the PC138. | Pause operation to allow cooling and check for possible oil or cooling system issues. | |
| Service / Hour Meter | AMBER | Scheduled maintenance interval has been reached based on operating hours of the PC138. | Perform required maintenance per the service schedule. | |
| Work Lights | GREEN | The work lights are currently switched on for improved visibility around the PC138. | No action needed unless lights are not required. | |
| Beacon / Rotating Light | AMBER | The safety beacon is active, signaling the PC138's presence on site. | Ensure beacon is functioning when operating in high-traffic areas. | |
| Parking Brake | RED | The parking brake is engaged, preventing the PC138 from moving. | Release the parking brake before attempting to travel. | |
| Swing / Slew Lock | AMBER | The swing lock is engaged, restricting upper structure rotation on the PC138. | Disengage the swing lock before rotating the upper structure. | |
| Overload / Capacity | RED | The PC138 is operating beyond its rated lifting capacity, risking tipping or structural damage. | Lower the load immediately to a safe level. |
21 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
- Blocked oil filter
What to do
For the PC138, immediately shut down the engine, check oil level and quality, and inspect for leaks or filter blockages before restarting.
Coolant Overtemperature Warning
Common causes
- Low coolant level
- Radiator blockage
- Faulty thermostat
What to do
Stop the PC138, allow it to cool, then check coolant level and radiator condition; consult Komatsu service if overheating persists.
Hydraulic System Fault
Common causes
- Hydraulic fluid leak
- Overheated hydraulic oil
- Damaged hydraulic pump
What to do
Inspect the hydraulic circuit of the PC138 for leaks, abnormal noises, or high temperatures; address fluid issues or contact service if unresolved.
Battery / Charging System Failure
Common causes
- Broken alternator belt
- Faulty alternator
- Loose battery connections
What to do
Check the alternator belt and battery terminals on the PC138; replace or repair faulty components to restore charging.
Overload / Capacity Warning
Common causes
- Lifting excessive load
- Incorrect attachment use
- Unstable machine position
What to do
Lower the load immediately and ensure the PC138 is used within rated limits and on stable ground.
Frequently Asked Questions
What should I do if the DPF / Regeneration light stays on in my PC138?
If the DPF light remains illuminated, follow the regeneration procedure in your operator's manual; if it does not clear, contact Komatsu service.
How can I reset the service/hour meter reminder on the PC138?
After performing scheduled maintenance, reset the hour meter through the monitor's service menu following the steps in the operator's guide.
Why does the hydraulic oil warning appear even after topping up fluid?
The warning may indicate excessive temperature or a sensor issue; inspect for leaks and ensure the oil is at the correct grade and level.
Is it safe to operate the PC138 if the master caution light is on?
You may continue working briefly, but review the monitor for details and address the caution as soon as possible to prevent escalation.
What causes the water in fuel indicator to come on in the PC138?
Water contamination in the fuel tank or filter triggers the warning; drain the water separator promptly to avoid engine damage.