The Hitachi ZX135US-6 is a compact, short-tail swing excavator designed for urban and confined job sites. Its advanced instrument cluster provides operators with precise, real-time alerts and status updates to ensure optimal machine performance and safety. Understanding the warning and indicator lights is essential for maintaining uptime and preventing costly damage.
Hitachi ZX135US-6 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | A critical system fault has been detected in the ZX135US-6, such as severe engine or hydraulic failure. | Safely stop operation and investigate the root cause immediately. | |
| Master Caution | AMBER | A non-critical system issue or abnormality has been identified by the machine’s monitoring system. | Review the cluster for detailed warnings and schedule inspection. | |
| Check Engine (MIL) | AMBER | The engine management system has logged a fault specific to the ZX135US-6’s Isuzu engine. | Check diagnostic codes using the monitor and consult service documentation. | |
| Engine Oil Pressure | RED | Engine oil pressure has dropped below safe operating levels for the ZX135US-6. | Shut down the engine immediately and check oil level and leaks. | |
| Battery / Charging | RED | The alternator is not charging the battery or there is a charging circuit issue. | Inspect the alternator, battery terminals, and wiring for faults. | |
| Coolant Temperature | RED | Engine coolant temperature has exceeded safe limits for the ZX135US-6. | Stop the engine, allow it to cool, and check coolant level and radiator. | |
| Hydraulic System | AMBER | A hydraulic system issue, such as excessive temperature or filter restriction, has been detected. | Inspect hydraulic fluid level and filters before continuing operation. | |
| Hydraulic Oil | AMBER | Hydraulic oil level is low or oil temperature is abnormal in the ZX135US-6. | Top up hydraulic oil or allow system to cool as needed. | |
| Low Fuel | AMBER | Fuel level is nearing empty; the ZX135US-6 will soon require refueling. | Plan to refuel at the next convenient interval. | |
| DEF / AdBlue | AMBER | The DEF (AdBlue) tank is low or there is a system fault affecting emissions control. | Refill DEF tank or check for contamination/errors. | |
| DPF / Regeneration | AMBER | The diesel particulate filter is regenerating or requires regeneration. | Follow on-screen prompts for automatic or manual regeneration. | |
| Water in Fuel | AMBER | Water has accumulated in the fuel separator, risking injector damage. | Drain the water separator promptly. | |
| Fuel Filter / Water Separator | AMBER | The fuel filter is clogged or water separator needs draining. | Replace the filter or drain water as soon as practical. | |
| Air Filter | AMBER | The air filter element is clogged, reducing engine efficiency. | Inspect and clean or replace the air filter. | |
| Engine Oil Temperature | RED | Engine oil temperature has reached a critical level in the ZX135US-6. | Stop the engine and allow it to cool before resuming work. | |
| Parking Brake | RED | The parking brake is engaged, preventing movement of the ZX135US-6. | Disengage the parking brake before moving the machine. | |
| Brake System | RED | A malfunction has been detected in the service brake system. | Do not operate until the brake fault is resolved. | |
| Swing / Slew Lock | AMBER | The swing lock is engaged, restricting upperstructure rotation. | Release the swing lock if you need to rotate the house. | |
| Service / Hour Meter | AMBER | Scheduled maintenance is due based on the ZX135US-6’s hour meter. | Perform the recommended service as indicated. | |
| Work Lights | BLUE | Work lights are switched on for improved visibility. | No action needed unless lights are not required. | |
| Beacon / Rotating Light | AMBER | The rotating beacon is activated for site safety. | Ensure beacon is functioning during site operation. | |
| Fasten Seat Belt | AMBER | The operator’s seat belt is not fastened, which is required for safe operation. | Buckle the seat belt before proceeding. |
22 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
On the ZX135US-6, immediately stop the engine, check oil level and top up if low, inspect for visible leaks, and replace the oil filter if necessary before restarting.
Coolant Temperature Warning
Common causes
- Low coolant level
- Radiator blockage
- Cooling fan failure
What to do
Shut off the ZX135US-6, allow it to cool, then inspect coolant level, check for radiator obstructions, and verify cooling fan operation.
Hydraulic System Warning
Common causes
- Hydraulic fluid low
- Filter element clogged
- Hydraulic pump overheating
What to do
Stop operation, check hydraulic reservoir level, inspect filter status, and allow the hydraulic system to cool before resuming use.
DEF / AdBlue Warning
Common causes
- DEF tank empty
- Contaminated DEF fluid
- DEF dosing system malfunction
What to do
Refill with high-quality DEF, inspect for contamination, and if the warning persists, have the system checked by an authorized Hitachi technician.
Fuel Filter / Water Separator Warning
Common causes
- Water in fuel separator
- Clogged fuel filter
- Poor fuel quality
What to do
Drain water from the separator, replace the filter if clogged, and ensure only clean, recommended diesel is used in the ZX135US-6.
Frequently Asked Questions
What should I do if the DPF regeneration light stays on?
Check the cluster for prompts and follow the procedure for parked or manual regeneration; if it doesn’t clear, contact your Hitachi service provider.
How do I check the hour meter for scheduled maintenance?
Press the menu button on the ZX135US-6’s monitor to view the current hour count and upcoming service intervals.
Is it safe to operate with the master caution light on?
While the machine may still function, you should investigate the cause and resolve it as soon as possible to avoid escalation.
Why does the hydraulic oil light flash intermittently?
This can occur if the oil level is just above the sensor threshold or if the oil temperature briefly rises during heavy use; check both conditions.
What happens if DEF runs out on the ZX135US-6?
The engine will enter a reduced power mode and, if ignored, may eventually prevent starting until the DEF system is refilled.