The Hino 155's instrument cluster features a range of warning lights tailored to its J08C engine and vocational applications. This guide decodes each indicator, helping you respond appropriately to keep your truck on the road.
Hino 155 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | Illuminates with a chime when a critical fault (e.g., oil pressure loss) requires you to stop the Hino 155 immediately. | Safely pull over, shut down engine, and check the accompanying warning message or light. | |
| Master Caution | AMBER | Activates for non-critical issues like low washer fluid or a minor sensor fault, alerting you to schedule service soon. | Refer to the secondary indicator that is also on and address as needed. | |
| Check Engine (MIL) | AMBER | Indicates a fault in the Hino J08C engine's emission control system, such as a bad oxygen sensor or EGR issue. | Have the diagnostic codes read by a Hino technician to identify and fix the underlying problem. | |
| Engine Oil Pressure | RED | Alerts to low oil pressure in your Hino 155, which can stem from low oil level, a failing pump, or a clogged filter. | Stop the engine immediately, check oil level, and if okay, call for roadside service. | |
| Battery / Charging | RED | Indicates the alternator isn't charging the battery, often due to a broken belt or wiring fault specific to the Hino 155. | Drive to a shop if possible, or stop to avoid a dead battery; check belt tension and connections. | |
| Coolant Temperature | RED | Signals the engine coolant is overheating, common when climbing grades with a loaded Hino 155 or in hot weather. | Pull over, let engine idle to cool, check coolant level, and inspect for leaks before resuming. | |
| Transmission Temp | AMBER | Warns that transmission fluid is too hot, often from heavy hauling or extended idling in the Hino 155. | Shift to a lower gear, reduce speed, and if light stays on, stop and let transmission cool. | |
| Brake System | RED | Indicates a fault in the air brake system, such as low air pressure or a relay valve issue on your Hino 155. | Do not drive; check air pressure gauges and park until brakes are repaired. | |
| ABS | AMBER | Lights up if there's a problem with the anti-lock braking system, like a wheel speed sensor fault on the Hino 155. | Standard brakes still work; have the ABS system diagnosed at your next service stop. | |
| Parking Brake | RED | Stays on when the parking brake is engaged, or flashes if the brake is not fully released on the Hino 155. | Ensure the parking brake knob is fully pushed in before driving. | |
| Seat Belt | RED | Reminds the driver to fasten their seat belt; stays on until buckled in the Hino 155. | Buckle your seat belt immediately. | |
| Glow Plug / Preheat | AMBER | Illuminates when the glow plugs are heating the intake air for cold starts on the Hino 155's diesel engine. | Wait for the light to turn off before cranking the engine. | |
| DPF / Regeneration | AMBER | Indicates the diesel particulate filter needs cleaning; the Hino 155 will perform active regeneration while driving. | Drive at highway speeds for 20-30 minutes to allow automatic regen; if flashing, manual regen may be needed. | |
| DEF / AdBlue | AMBER | Warns that DEF fluid is low or quality is poor; the Hino 155's SCR system needs DEF to reduce emissions. | Refill DEF at the next stop; if light remains, have system inspected for contamination. | |
| Water in Fuel | AMBER | Alerts that water has accumulated in the fuel filter/water separator, which can cause injection issues on the Hino 155. | Drain the water separator located on the fuel filter housing as soon as possible. | |
| Low Fuel | AMBER | Indicates the fuel level is low; the Hino 155 has a reserve of about 10% capacity remaining. | Refuel at the nearest station to avoid running out. | |
| High Beam | BLUE | Blue indicator shows the high-beam headlights are on, improving night visibility on your Hino 155. | Dim to low beams when approaching oncoming traffic. | |
| Power Steering (EPS) | AMBER | Indicates an issue with the electric power steering system, making steering heavier on the Hino 155. | Check power steering fluid level if hydraulic; if electric, have system scanned. | |
| Reduced Power (Limp Mode) | AMBER | Engine power is limited to prevent damage, often due to a transmission or emission fault on the Hino 155. | Drive at reduced speed to the nearest service center and have error codes read. | |
| Air Brake Pressure (Low) | RED | Air brake pressure is below safe operating level; the Hino 155's air system may have a leak or compressor issue. | Do not drive; wait for air pressure to build; if it doesn't, call for repair. | |
| Engine / Exhaust Brake | GREEN | Green light indicates the exhaust brake is active, aiding in downhill speed control on the Hino 155. | The brake is operating normally; no action needed unless light flashes (fault). | |
| High Exhaust Temp (HEST) | AMBER | Warns that exhaust temperatures are elevated during DPF regeneration on the Hino 155. | It's normal during regen; avoid parking near flammable materials. |
22 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Low Engine Oil Pressure
Common causes
- Low oil level due to consumption or leaks
- Faulty oil pump
- Clogged oil filter or pickup screen
What to do
Pull over immediately and shut off the engine. Check the dipstick; if low, add oil. If level is fine, do not restart — call a Hino specialist to inspect the pump or internal engine issues.
Engine Overheating
Common causes
- Low coolant level from leak
- Failed thermostat or water pump
- Clogged radiator or fan issue
What to do
Stop the truck and let the engine idle (if not overheating severely) to cool. Check coolant reservoir when safe; do not open hot cap. Top off with approved coolant and inspect for leaks. If problem persists, replace thermostat or get radiator serviced.
Low Air Brake Pressure
Common causes
- Air leak in brake lines or chambers
- Faulty air compressor or governor
- Moisture freezing in system (cold weather)
What to do
Do not move the truck. Start engine to let compressor build pressure. If pressure does not rise above 60 psi, check for air leaks with soapy water, or have a technician inspect the compressor and governor.
DEF/AdBlue System Failure
Common causes
- Contaminated or incorrect DEF fluid
- DEF pump or heater malfunction
- Clogged DEF injector or NOx sensor failure
What to do
Refill with genuine Hino DEF if low. If light stays on, the truck may derate. Have the SCR system diagnosed — common issues include a failed DEF pump or crystallized injector requiring replacement.
DPF Regeneration Active/Fault
Common causes
- Frequent short trips preventing passive regen
- High soot load due to engine issues
- Failed DPF pressure sensor or temperature sensor
What to do
Drive at highway speeds for 20–30 minutes to allow active regeneration. If flashing or light remains, parked regeneration may be required — follow Hino procedure. If regen fails, the DPF may need forced cleaning or replacement at a dealership.
Frequently Asked Questions
What does the DPF regeneration light mean on my Hino 155?
The light indicates the diesel particulate filter needs cleaning. On the Hino 155, this typically happens automatically at highway speeds. If it flashes, you may need to perform a stationary regen via the dashboard switch.
Why is the ABS light on and how do I fix it?
The ABS light means a fault in the anti-lock system, often a dirty or damaged wheel speed sensor. The brakes still work, but have the codes read at a Hino shop — it's usually a simple sensor replacement.
How do I reset the service (hour meter) light after an oil change?
Turn the ignition to 'ON', then press and hold the trip/reset button on the dash for 5 seconds until the light flashes and then turns off. This resets the service interval on Hino 155 models.
What should I do if the water-in-fuel light comes on?
Pull over safely and locate the fuel/water separator under the hood. Open the drain valve on the bottom of the filter bowl and let water drain until pure fuel flows. Close the valve; the light should soon go out.
How often should I check the DEF (AdBlue) level on my Hino 155?
Check at every fuel stop; the Hino 155's DEF tank holds about 5 gallons. Refill when the warning light appears — running out can cause engine derate and require dealer reset.
Why does the engine temperature gauge stay cold, but the cold coolant light is on?
If the blue 'cold coolant' light stays on after warm-up, it likely means a stuck-open thermostat. Replace the thermostat to allow the engine to reach proper operating temperature for the Hino 155.