The Kenworth T680's instrument cluster features a high-resolution display and analog gauges designed to keep the driver informed of critical truck systems. With its advanced SmartLine dashboard, the T680 integrates warnings and alerts specific to the PACCAR engine and Eaton transmission, ensuring optimal performance and safety on the road.
Kenworth T680 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | This red stop light appears when a critical fault is detected, such as a sudden loss of engine oil pressure or an immediate overheat condition, requiring the driver to pull over and shut down the engine in the T680. | Safely pull over, turn off the engine, and consult the SmartLine display for the specific fault code before calling for service. | |
| Master Caution | AMBER | An amber caution light activates when a non-critical system requires attention, like a low DEF level or a pending DPF regeneration in your T680. | Check the information display for the specific caution message and address the issue at the next available stop. | |
| Check Engine (MIL) | AMBER | This amber engine symbol illuminates when the PACCAR MX-13 engine control unit detects a malfunction that affects emissions or performance, such as a faulty sensor or exhaust gas recirculation issue. | Schedule a diagnostic service with a Kenworth dealer to read the fault codes and determine necessary repairs. | |
| Engine Oil Pressure | RED | In the T680, a red oil can icon indicates that the engine oil pressure has dropped below safe operating levels, often due to low oil or a failing oil pump. | Immediately stop the engine and check the oil level; if sufficient, do not restart and have the truck towed to a service center. | |
| Battery / Charging | RED | This red battery warning in the T680 signals that the alternator is not charging properly or the battery voltage is critically low, possibly due to a loose belt or failed alternator. | Reduce electrical loads and drive to the nearest service facility; if the warning persists, have the charging system inspected. | |
| Coolant Temperature | RED | A red temperature gauge or warning in the T680 indicates that the engine coolant has exceeded safe limits, often from a clogged radiator or low coolant level. | Pull over safely, allow the engine to idle down, and check coolant level after cooling; do not continue driving if overheated. | |
| Transmission Temp | AMBER | The amber transmission temperature light in the T680 warns that the Eaton Fuller transmission fluid is too hot, often from excessive load or low fluid level. | Reduce speed and shift to a lower gear to allow cooling; if warning stays, stop and let the transmission cool before checking fluid. | |
| Brake System | RED | This red brake warning in the T680 indicates a failure in the air brake system, such as low air pressure or a brake imbalance, requiring immediate attention. | Stop the vehicle safely and check the air pressure gauges; if below 60 psi, do not drive until the system is repaired. | |
| ABS | AMBER | The amber ABS light in the T680 signals a fault in the anti-lock braking system, which may still allow normal braking but reduces stability during hard stops. | Have the ABS system diagnosed at the next service stop; standard braking remains functional. | |
| Parking Brake | RED | In the T680, this red indicator shows that the parking brake is engaged, ensuring the truck remains stationary when parked; it is normal when the brake is set. | Release the parking brake before driving; if the light stays on with brake released, check the brake switch or air system. | |
| Tire Pressure (TPMS) | AMBER | The amber TPMS light in the T680 indicates that one or more tires have low pressure, which can reduce fuel efficiency and tire life. | Check tire pressures at the next opportunity and inflate to the recommended PSI for your T680. | |
| Seat Belt | RED | This red seat belt icon reminds the T680 driver that the driver's seat belt is not fastened; it will typically sound a chime until secured. | Fasten your seat belt immediately for safety and compliance with regulations. | |
| Glow Plug / Preheat | AMBER | On cold starts in the T680, this amber coil symbol indicates that the engine glow plugs are heating the intake air to aid ignition; it turns off when starting is possible. | Wait for the indicator to turn off before cranking the engine to ensure a smooth cold start. | |
| DPF / Regeneration | AMBER | In the T680, this amber exhaust filter icon signals that the Diesel Particulate Filter is approaching its soot load limit and requires regeneration to burn off trapped particles. | If driving, maintain highway speed for about 20 minutes to allow passive regeneration; if the light blinks, initiate a stationary regen via the SmartLine menu. | |
| DEF / AdBlue | AMBER | This amber DEF level warning in the T680 indicates that the Diesel Exhaust Fluid tank is low and needs refilling to continue meeting emissions standards. | Add DEF at the next fuel stop; the T680 will limit speed if the level becomes critically low. | |
| Water in Fuel | AMBER | In the T680, this amber water drop symbol warns that water has accumulated in the fuel filter/water separator, which can damage the fuel injection system. | Drain the water separator at the fuel filter service point as soon as possible to prevent injection issues. | |
| Low Fuel | AMBER | The amber low fuel light in the T680 activates when the fuel level is low, prompting the driver to refuel to avoid running out on the road. | Refuel at the next available station; the T680 has a large tank but reserve varies. | |
| High Beam | BLUE | This blue high beam indicator confirms that the high beam headlights are on in your T680, providing maximum illumination on dark roads. | Dim the high beams when approaching oncoming traffic to avoid glare. | |
| Reduced Power (Limp Mode) | AMBER | An amber engine or wrench symbol in the T680 indicates that the engine control unit has limited power to prevent damage, often due to a high exhaust temperature condition or malfunction. | Drive at reduced speed to the nearest service facility; the truck will not achieve full power until the issue is resolved. | |
| Air Brake Pressure (Low) | RED | In the T680, a red air brake warning comes on when the air pressure in the brake system drops below 60 psi, making it unsafe to drive. | Do not move the truck; allow the air compressor to build pressure or repair the air system leak before driving. | |
| Engine / Exhaust Brake | GREEN | This green indicator in the T680 shows that the exhaust brake or engine brake is active, providing additional stopping power on downgrades. | Use the exhaust brake to reduce brake wear; it is normal when engaged. | |
| Trailer | AMBER | An amber trailer icon in the T680 warns of a malfunction in the trailer electrical or lighting system, such as a burned-out turn signal or brake light. | Inspect the trailer lights and connectors; repair any faults to ensure safety. | |
| High Exhaust Temp (HEST) | AMBER | In the T680, this amber exhaust temperature light activates during DPF regeneration, indicating that the exhaust system is very hot and may ignite flammable materials. | Avoid parking over dry grass or debris; continue driving to complete the regeneration cycle. | |
| Door Open | RED | The red open door icon in the T680 warns that the driver's door is ajar, which could lead to an accident or battery drain if left open. | Close the door securely before moving the truck. |
24 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Engine Overheat
Common causes
- Low coolant level
- Radiator obstruction
- Faulty thermostat
- Coolant fan failure
What to do
Pull over immediately and let the engine idle down. Check coolant level after cooling. For your T680, ensure the SmartLine shows no active faults; if coolant is low, top off with approved coolant and inspect for leaks.
Low Air Brake Pressure
Common causes
- Air system leak
- Failed air compressor
- Frozen air lines (cold weather)
What to do
Do not drive if pressure is below 60 psi. In your T680, listen for air leaks from brake chambers or lines. If pressure builds while stationary, you may have a minor leak; if not, have the air system inspected by a Kenworth technician.
Sudden Loss of Oil Pressure
Common causes
- Oil pump failure
- Severe oil leak
- Low oil level
What to do
Shut down the engine immediately to avoid catastrophic damage. Check the oil level on your T680's dipstick; if low, add oil and restart. If pressure does not return, do not run the engine and call for roadside assistance.
Electrical System Failure
Common causes
- Failed alternator
- Loose or corroded battery connections
- Blown fuse
What to do
Check battery terminals for corrosion and tightness. In the T680, the alternator is critical; if the voltmeter shows less than 12 volts while running, the alternator may be faulty. Drive only to the nearest shop to avoid a dead battery.
DPF Clogged (Regeneration Required Immediately)
Common causes
- Frequent short trips
- Low exhaust temperature
- Faulty sensors
What to do
Initiate a stationary regeneration via the T680's SmartLine menu if the DPF light is flashing. If regeneration fails, the truck may derate power; take it to a Kenworth dealer for forced regeneration or filter cleaning.
Frequently Asked Questions
What should I do if the DEF warning light comes on in my T680?
The amber DEF light means the AdBlue level is low. Refill with fresh DEF at your next fuel stop. The T680 will gradually reduce power if the level drops too low, so avoid waiting until the last minute.
Why does my T680's check engine light stay on after an oil change?
The check engine light may be due to a sensor reset not completed or a different fault. In the T680, the PACCAR MX-13 engine monitors many parameters; use the SmartLine to read fault codes or visit a dealer to clear the light if no issue exists.
How do I know if my T680 needs a DPF regeneration?
The DPF symbol will illuminate solid amber when soot load is high, or blink when regeneration is urgent. The T680's system can perform automatic regeneration while driving at highway speeds; if it blinks, initiate a parked regen via the gauge cluster menu.
What causes the transmission temperature warning in my T680?
High temperature in the Eaton Fuller transmission can be caused by heavy loads, continuous stop-and-go traffic, or low transmission fluid level. In the T680, reduce gear and load if possible; if the light stays on, check fluid level and inspect for leaks.
Can I continue driving with the ABS warning light on?
Yes, the amber ABS light means the anti-lock system is disabled, but standard brakes still work. However, in the T680, be cautious on slippery surfaces. Schedule a diagnostic at your earliest convenience to restore full braking safety.
What does the 'High Exhaust Temp' indicator mean on my T680?
This light comes on during DPF regeneration, indicating the exhaust is extremely hot. In the T680, avoid parking over dry grass or debris. Continue driving until the cycle completes and the light turns off.