Warning and Indicator Lights

Common Lightbar Lamps

CHECK Engine

Indicates a critical engine condition (low oil pressure, low coolant level, high coolant temperature, high DPF soot level, or uncontrolled DPF regeneration). Correct the condition as soon as possible. If the condition worsens, the STOP engine lamp will illuminate.

STOP Engine

Indicates a serious fault which requires engine shutdown immediately. The engine protection system will reduce the maximum engine torque and speed, and, if the condition does not improve, will shut down the engine within 30 to 60 seconds.

The driver must safely bring the vehicle to a stop on the side of the road and shut down the engine as soon as the red light is seen. If the engine shuts down while the vehicle is in a hazardous location, restart the engine after turning the key to the OFF position for a few seconds. Move the vehicle to a safer location.

High Exhaust System Temperature (HEST)

Slow (10-second) flashing indicates a regeneration (regen) is in progress.

Solid illumination indicates high exhaust temperatures at the outlet of the tail pipe, when speed is below 5 mph (8 km/h). It does not signify the need for service; it only alerts the vehicle operator to high exhaust temperatures when a regen is in progress.

Diesel Particulate Filter (DPF) Status

Solid illumination indicates a regen is required. Change to a more challenging duty cycle (such as highway driving ) to raise exhaust temperatures for at least twenty minutes, or perform a parked regen.

Blinking indicates that a parked regen is required immediately. An engine derate and shutdown will occur.

Malfunction Indicator Lamp (MIL)

Indicates an engine emissions-related fault. See the engine operation manual for details.

Left-Turn Arrow

Flashes on and off whenever the outside left-turn signal lights are activated.

Right-Turn Arrow

Flashes on and off whenever the outside right-turn signal lights are activated.

High-Beam Headlights

Indicates the high-beam headlights are on.

Daytime Running Lights

Indicates the daytime running lights are on.

Tractor ABS

Indicates a problem with the truck/tractor ABS is detected. Repair the vehicle ABS immediately to ensure full braking capability.

Trailer ABS

Indicates a problem with the trailer ABS is detected. Repair the trailer ABS immediately to ensure full braking capability.

Low Air Pressure

Activates with an audible warning when air pressure in the primary or secondary reservoir falls below 70 psi (483 kPa).

Parking Brake

Indicates the parking brake is engaged.

Power Takeoff (PTO)

Indicates that the PTO function is engaged.

Unfastened Seat Belt

Illuminates with the ignition ON and the driver seat belt unfastened.

Water In Fuel

Indicates that the fuel may contain water. The driver must drain any water collected in the fuel/water separator.

Fuel Filter Restriction

Indicates the fuel filter has been clogged and requires service.

Wait To Start

Illuminates when starting the engine during cold conditions. Wait until the lamp goes out before turning the ignition key to START.

Transmission Overheat

Indicates high transmission temperature.

Check Transmission

Indicates an undesirable transmission condition.

Service Transmission

Indicates a transmission service is due.

Rear Suspension Low Air Pressure

Indicates that the rear suspension air pressure is below operating range.

Wheel Spin (pre-EPA16)

Flashing indicates the ATC system is active, or the ATC button has been pressed to allow wheel slip.

Solid illumination indicates ATC is shut off or unavailable due to a system fault. In the event of a system fault, repair the ATC system immediately to ensure full braking capability.

Stability Event (EPA16 and newer)

Flashing indicates a stability event has been detected, and the ESC system is active. Solid illumination indicates a problem with the stability system. Repair the ESC system immediately to ensure full stability capability.

ATC Deactivated (EPA16 and newer)

Flashing indicates the ATC SPIN button has been pressed to allow wheel slip.

Solid illumination indicates ATC is shut off or unavailable due to a system fault. In the event of a system fault, repair the ATC system immediately to ensure full braking capability.

Roll Stability (pre-EPA16)

Momentary illumination indicates that a stability event has occurred.

On vehicles that are also equipped with ATC, flashing indicates the ATC button has been pressed to allow wheel slip. Solid illumination indicates ATC is shut off or unavailable due to a system fault. In the event of a system fault, repair the ATC system immediately to ensure full braking capability.