The International LT is a heavy-duty semi truck engineered for long-haul efficiency, featuring a suite of driver-focused warnings and information displays. This guide explains the indicator lights on the LT's instrument cluster to help you respond appropriately.
International LT Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop Engine) | RED | On the International LT, this red stop sign symbol indicates a critical fault that requires you to pull over and shut down the engine immediately to prevent major damage. | Stop the truck safely, turn off the engine, and contact International service support. | |
| Master Caution | AMBER | An amber triangle with an exclamation point on the LT signals a non-critical fault that needs your attention at the earliest opportunity. | Check the message center for details and schedule service soon. | |
| Check Engine (MIL) | AMBER | When lit on the LT's cluster, this symbol indicates the engine management system has detected a fault that may affect emissions or performance. | Reduce power if needed and have the engine diagnosed by an International dealer. | |
| Engine Oil Pressure | RED | On the International LT, low engine oil pressure is indicated by an oil can symbol; continued operation can cause severe engine damage. | Pull over, turn off the engine, check oil level, and do not restart if low. | |
| Battery / Charging | RED | This red battery symbol on the LT warns that the charging system voltage is too low or the alternator is not working. | Reduce electrical loads and drive to a service center; if the light stays on, stop and call for help. | |
| Coolant Temperature | RED | A red thermometer symbol on the LT means the engine coolant is overheating, which can cause engine failure if ignored. | Pull over, let the engine idle to cool down, check coolant level after cooling. | |
| Transmission Temp | AMBER | An amber gear symbol with a thermometer on the LT indicates the transmission fluid is hotter than normal, often due to heavy load or hill climbing. | Reduce speed, shift to a lower gear, or stop and idle to cool down. | |
| Brake System | RED | A red circle with 'BRAKE' on the LT warns of a problem with the service brakes or brake fluid level. | Stop immediately in a safe area, do not drive until the brake system is inspected. | |
| ABS | AMBER | An amber ABS symbol on the LT indicates a fault in the anti-lock braking system; standard braking remains but ABS function is lost. | Drive cautiously and have the system checked at the next service stop. | |
| Parking Brake | RED | A red 'P' in a circle on the LT cluster illuminates when the parking brake is applied, and should turn off before moving. | Release the parking brake before driving; if it stays on, check air pressure or brake valve. | |
| Tire Pressure (TPMS) | AMBER | An amber tire cross-section symbol on the LT alerts you that one or more tires are significantly underinflated. | Check all tire pressures and inflate to recommended levels as soon as possible. | |
| Airbag (SRS) | AMBER | An amber seated figure with a deployed airbag on the LT indicates a fault in the supplemental restraint system. | Have the SRS inspected by a qualified technician; airbags may not deploy in a crash. | |
| Seat Belt | RED | A red seat belt symbol on the LT reminds the driver that the belt is not fastened; the truck will not allow driving until buckled. | Fasten your seat belt immediately. | |
| Glow Plug / Preheat | AMBER | An amber coil symbol on the LT indicates the intake air heater is active for cold start assistance; it turns off when the engine is ready. | Wait for the light to go out before cranking the engine. | |
| DPF / Regeneration | AMBER | An amber particulate filter symbol on the LT means the diesel particulate filter is being regenerated to burn off soot; exhaust temperature rises. | Continue driving normally; if flashing, a manual regeneration is needed soon. | |
| DEF / AdBlue | AMBER | An amber DEF symbol on the LT warns that the diesel exhaust fluid level is low or quality is poor, which can limit vehicle speed. | Add DEF at the next opportunity; if ignored, engine power will be reduced. | |
| Water in Fuel | AMBER | An amber fuel pump with a water droplet on the LT indicates that water has accumulated in the fuel/water separator; drain it to avoid injector damage. | Drain the water separator as soon as possible; refer to the owner's manual. | |
| Low Fuel | AMBER | An amber fuel pump symbol on the LT illuminates when fuel level is low; the range to empty will be shown on the display. | Refuel as soon as possible to avoid running out. | |
| High Beam | BLUE | A blue headlight symbol on the LT indicates that the high-beam headlights are on. | Dim your high beams when approaching oncoming traffic. | |
| Power Steering (EPS) | RED | A red steering wheel symbol on the LT warns of a power steering system fault, making steering difficult. | Pull over safely and have the system inspected immediately; do not continue driving. | |
| Reduced Power (Limp Mode) | AMBER | An amber turtle or engine symbol on the LT indicates the engine control unit has limited power to protect the drivetrain from damage. | Drive at reduced speed to the nearest service center; check for fault codes. | |
| Air Brake Pressure (Low) | RED | A red air pressure gauge symbol on the LT warns that air system pressure is below safe braking level. | Stop immediately; do not drive until pressure is restored and warning light turns off. | |
| Engine / Exhaust Brake | GREEN | A green 'R' or exhaust brake symbol on the LT indicates that the auxiliary braking system is activated to assist downhill speed control. | Use this feature on steep grades to reduce service brake wear. | |
| Trailer | GREEN | A green trailer symbol on the LT lights up when the trailer is electrically connected and recognized by the truck's system. | Verify all trailer lights are working before departure. |
24 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Low Air Brake Pressure
Common causes
- Air leak in the brake system
- Failed air compressor
- Gladhand not connected properly
What to do
Stop the LT immediately; check all air lines and connections. If pressure doesn't build, call roadside assistance. Do not attempt to move the truck without proper air pressure.
Engine Overheating
Common causes
- Low coolant level
- Failed thermostat or water pump
- Clogged radiator or cooling fan issue
What to do
Pull over, let the LT idle with the hood open to cool down. Check coolant level only when engine is cool. If the problem persists, have the cooling system inspected by a technician.
Low Oil Pressure
Common causes
- Insufficient engine oil
- Oil pump failure
- Clogged oil filter or internal leak
What to do
Stop the LT and turn off the engine immediately. Check oil level and add if needed. If the light stays on, do not restart; have the oil system diagnosed by an International dealer.
Charging System Failure
Common causes
- Broken alternator belt
- Failed alternator
- Battery cable corrosion or loose connection
What to do
Reduce electrical load and head to the nearest service center. If the LT stalls, call for roadside assistance. Have the charging system tested and repaired.
DEF System Malfunction
Common causes
- Empty DEF tank
- Defective DEF quality sensor
- Plugged DEF injector
What to do
Add fresh DEF if low. If the warning persists, the LT will eventually derate power; schedule service to diagnose the DEF system.
Frequently Asked Questions
Why does my International LT show a flashing check engine light?
A flashing check engine light on the LT indicates a severe misfire that can damage the catalytic converter. Reduce speed immediately and have the truck inspected by an International dealer.
How do I reset the DPF regeneration light on my LT?
The DPF regeneration light should turn off once the process completes automatically. If it remains on or flashes, you may need to activate a manual regeneration via the switch on the dash or through the infotainment menu.
What does the amber 'Water in Fuel' light mean for my LT?
It means water has collected in the fuel/water separator. Drain it by opening the valve at the bottom of the separator, usually located near the fuel filter, to prevent injector damage.
Can I drive my International LT with the ABS light on?
You can, but ABS is disabled. The standard brakes still work, but the truck will not have anti-lock function. Drive cautiously and have the system checked soon.
How do I check the DEF level on my International LT?
The DEF level is displayed on the instrument cluster or infotainment screen. When low, the amber DEF light will illuminate. Fill the DEF tank with fresh diesel exhaust fluid at the next stop.
What should I do if the 'Reduced Power' light comes on while hauling?
The LT has entered limp mode to protect the engine. Reduce speed and find a safe place to stop. Check for any other warnings and call International service for diagnosis before continuing.