The Hino 338 instrument cluster provides real-time feedback on your truck's systems, from the J08E engine to the Allison automatic transmission. Familiarity with these indicators ensures safe operation and helps prevent roadside breakdowns.
Hino 338 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | On the Hino 338, this red stop light illuminates with a buzzer when a critical fault occurs, such as loss of oil pressure or brake air pressure. | Safely pull over and shut down the engine immediately. Check the primary warning light for the specific issue. | |
| Master Caution | AMBER | This amber light in the Hino 338 alerts you to a non-critical system fault or maintenance reminder, such as a pending DPF regeneration. | Review the secondary warning lights and address the indicated system at the earliest opportunity. | |
| Check Engine (MIL) | AMBER | On the Hino 338, the malfunction indicator lamp signals an engine or emissions system fault, often related to the J08E engine's electronic controls. | Have the engine scanned by a Hino dealer; continued driving is possible if power is not reduced, but schedule service soon. | |
| Engine Oil Pressure | RED | For the Hino 338, this red oil can symbol indicates critically low engine oil pressure, risking severe damage to the J08E engine. | Stop the engine immediately and check oil level; do not restart until the issue is resolved. | |
| Battery / Charging | RED | On the Hino 338, this red light shows the alternator is not charging the batteries, or there is a voltage out of range. | Check alternator belt and battery connections; if light stays on, replace the alternator to avoid a dead battery. | |
| Coolant Temperature | RED | On the Hino 338, this red light warns that the coolant temperature has exceeded safe limits, often due to low coolant or a stuck thermostat. | Pull over, idle with the hood open, and check coolant level after the engine cools; do not remove the cap while hot. | |
| Transmission Temp | AMBER | On the Hino 338, this amber light indicates the Allison automatic transmission fluid is overheating, which can lead to clutch damage. | Reduce speed and shift to a lower gear to increase RPM and oil flow; if light persists, stop and let the transmission cool. | |
| Brake System | RED | On the Hino 338, this red light signals a general brake fault such as low brake fluid or a pressure imbalance in the air-over-hydraulic system. | Check brake fluid reservoir and air pressure gauges; do not drive until the brake system is inspected. | |
| ABS | AMBER | On the Hino 338, this amber light indicates a problem with the anti-lock braking system, which could affect braking on slippery surfaces. | Standard brakes still function; have the ABS system diagnosed at a qualified shop. | |
| Parking Brake | RED | On the Hino 338, this red light shows the parking brake is engaged; it should be off before moving. | Release the parking brake fully before shifting into gear. | |
| Tire Pressure (TPMS) | AMBER | On the Hino 338, this amber light alerts you that one or more tires are significantly underinflated, as monitored by the tire pressure sensors. | Check tire pressures with a gauge and inflate to the recommended PSI; if light persists, inspect for leaks. | |
| Airbag (SRS) | AMBER | On the Hino 338, this amber symbol indicates a fault in the supplemental restraint system, which may prevent airbag deployment in a crash. | Have the SRS system inspected by a Hino dealer as soon as possible. | |
| Seat Belt | RED | On the Hino 338, this red reminder signals that the driver's seat belt is not fastened. | Fasten your seat belt immediately to ensure safety and comply with regulations. | |
| Glow Plug / Preheat | AMBER | On the Hino 338 with the J08E engine, this amber coil symbol illuminates while the glow plugs are heating for cold starts. | Wait for the light to turn off before attempting to start the engine in cold weather. | |
| DPF / Regeneration | AMBER | On the Hino 338, this amber light indicates the diesel particulate filter needs active regeneration to clear soot buildup. | Drive at highway speed for 20–30 minutes to allow passive regeneration; if flashing, pull over and initiate stationary regen. | |
| DEF / AdBlue | AMBER | On the Hino 338, this amber light warns that the diesel exhaust fluid level is low, which will eventually limit engine power. | Refill the DEF tank with approved fluid as soon as possible to avoid reduced power. | |
| Water in Fuel | AMBER | On the Hino 338, this amber light indicates water has accumulated in the fuel/water separator, which can damage the fuel system. | Drain the water separator located near the fuel filter until clear fuel flows. | |
| Low Fuel | AMBER | On the Hino 338, this amber pump symbol warns that the fuel level is low and the engine may stall soon. | Refuel at the nearest station; running out of fuel can require bleeding the fuel system. | |
| High Beam | BLUE | On the Hino 338, this blue indicator confirms the high-beam headlights are on. | Dim to low beams when approaching other traffic to avoid blinding other drivers. | |
| Air Brake Pressure (Low) | RED | On the Hino 338, this red light and buzzer signal low air pressure in the brake system, below the safe threshold of 60 psi. | Stop immediately and allow the air compressor to build pressure; do not drive until pressure is normal. | |
| Reduced Power (Limp Mode) | AMBER | On the Hino 338, this amber light indicates the engine control unit has limited power to protect the powertrain from damage. | Drive cautiously to a service location; the cause often requires dealer diagnostics. |
21 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Engine Overheating
Common causes
- Low coolant level
- Faulty thermostat
- Blocked radiator
What to do
On the Hino 338, pull over immediately and idle the engine with the hood open. After cooling, check the coolant reservoir, inspect for leaks, and replace the thermostat if necessary.
Low Oil Pressure
Common causes
- Low oil level
- Oil pump failure
- Clogged oil filter
What to do
For the Hino 338, stop the engine instantly to prevent J08E engine seizure. Check the dipstick and add oil if low; if light stays on, have the oil pump and filter inspected.
Air Brake Failure
Common causes
- Air compressor failure
- Brake line leak
- Faulty brake valve
What to do
On the Hino 338, if the air pressure warning light comes on, park in a safe area and let the compressor recharge. If pressure doesn't build, check for air leaks and repair; do not drive without proper air pressure.
DEF System Malfunction
Common causes
- Low DEF fluid
- Clogged DEF injector
- Faulty NOx sensor
What to do
On the Hino 338, refill DEF if low. If the light persists, the DEF dosing system may need cleaning or sensor replacement at a Hino dealer to avoid derate.
Transmission Overheating
Common causes
- Overloading
- Low transmission fluid
- Faulty cooler
What to do
On the Hino 338 with Allison transmission, reduce load and drive at lower speeds. Check fluid level and condition; if overheating continues, inspect the transmission cooler for blockages.
Frequently Asked Questions
What should I do if the Master Warning light comes on while driving my Hino 338?
Pull over immediately and shut off the engine. The Master Warning indicates a critical fault—check the associated warning light (e.g., oil pressure or brake system) to identify the issue before restarting.
How often should I initiate DPF regeneration on my Hino 338?
The DPF regeneration process is automatic, but if the amber DPF light stays on, you may need to perform a stationary regeneration. Refer to your owner's manual; typically, it's needed every 200–300 hours of operation.
The ABS light is on but my brakes seem fine. Can I still drive?
Yes, standard braking is unaffected, but the anti-lock function is disabled. Drive cautiously and have the ABS system diagnosed at a Hino dealer as soon as possible.
What does the 'Water in Fuel' warning mean for my Hino 338?
It means water has separated in the fuel/water separator. Drain the water by turning the petcock at the bottom of the filter housing until clear fuel flows; this prevents fuel injection damage.
Why does my Hino 338 have reduced power and what should I do?
Reduced power (limp mode) activates to protect the engine from damage. Common causes include a faulty sensor, high exhaust temperature, or DEF system issues. Drive gently to a repair facility for diagnostics.
The air brake pressure warning won't shut off. What's wrong?
This indicates a leak or compressor problem. Check for hissing sounds around air lines and fittings. If you can't find the leak, have the system inspected by a truck mechanic; do not drive without full pressure.