Freightliner Warning Lights and Meanings
Complete guide to Freightliner dashboard warning lights and symbols. Learn what each indicator means and what action you should take when they illuminate.
Understanding Freightliner Dashboard Warning Lights
Freightliner vehicles are equipped with an advanced diagnostic system that monitors various components and systems. When an issue is detected, a corresponding warning light will illuminate on your dashboard.
These warning lights are color-coded to indicate the severity of the issue:
- Red: Indicates a serious issue that requires immediate attention. You should stop driving as soon as it's safe to do so.
- Amber/Yellow: Suggests a less urgent problem that should be checked soon, but doesn't require immediate action.
- Green: Usually informational, indicating that a system is active or functioning normally.
- Blue: Usually informational, indicating features like high beam headlights or coolant temperature.
- White: Usually informational, indicating that certain systems or features are currently active.
Below you'll find a comprehensive list of warning lights that may appear on your Freightliner vehicle's dashboard.
Freightliner Warning Light Categories
Critical Warning Lights
These red warning lights indicate serious issues that require immediate attention.
Service Warning Lights
These amber/yellow lights suggest issues that need attention soon but aren't immediately critical.
Information Indicators (Green)
These green lights simply inform you that certain systems are active.
Information Indicators (Blue)
These blue lights indicate that certain features or systems are enabled.
Critical Warning Lights
Check ECAS
Indicates Electronically Controlled Air Suspension (ECAS) active fault.
High Coolant Temperature
Indicates the coolant temperature is above the maximum allowable temperature.
Low Air Pressure
Indicates air pressure in the primary or secondary reservoir has dropped below approximately 70 psi (483 kPa).
Low Air Pressure
Indicates air pressure in the primary or secondary reservoir has dropped below approximately 70 psi (483 kPa).
Low Engine Oil Pressure
Indicates the engine oil pressure is below the minimum allowable pressure.
Parking Brake
Indicates the parking brake is engaged.
Parking Brake
Indicates the parking brake is engaged, or hydraulic brake fluid pressure is low. An audible alert activates when the vehicle is moving over 2 mph (3 km/h) with the parking brake set.
STOP Engine
Indicates a serious fault that 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. 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, turn the key to the OFF position for a few seconds, then restart the engine and move the vehicle to a safer location.
Steerable Tag Axle Warning
The steerable tag axle indicator activates when there is a loss of air pressure at the axle. Air pressure is needed to lock and unlock the steerable tag axle.
Transmission Fluid Level
Indicates low transmission fluid level. Safely bring the vehicle to a stop as soon as possible.
Transmission Overheat
Indicates high transmission temperature.
Unfastened Seat Belt
Activates with an audible alert when the system detects that the parking brake is off and the driver seat belt is not fastened on some vehicles. On other vehicles, this lamp illuminates for 15 seconds when the ignition is first turned on.
Service Warning Lights
ATC Deactivated
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.
Active Brake Assist
Indicates the Active Brake Assist system is not available.
Bulb Out
Indicates that a bulb is not functioning in the headlights, tail lights, parking lights, or marker lights.
CHECK Engine
Indicates an engine condition (low oil pressure, low coolant level, high coolant temperature, high DPF soot level, or uncontrolled DPF regeneration) that requires correction. Correct the condition as soon as possible. If the condition worsens, the STOP engine lamp will illuminate.
Check Transmission
Indicates an undesirable transmission condition.
Diesel Particulate Filter 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
Electronic Stability Control Indicator
The electronic stability control (ESC) indicator illuminates when the ESC system activates.
Forward Collision System Indicator
The forward collision system indicator illuminates only when the system is not available.
Fuel Filter Restriction
Indicates the fuel filter is clogged and requires service.
High Exhaust System Temperature
Slow (10-second) flashing indicates a regeneration (regen) is in progress. IMPORTANT: When the HEST lamp is illuminated, do not park the vehicle near flammable material. Solid illumination indicates high exhaust temperatures at the outlet of the tail pipe when speed is below 5 mph (8 km/h).
Hill Start Aid Override
Indicates the HSA switch has been pressed to override the hill start assist feature.
Lane Departure Warning
Indicates that lane departure warning is disabled due to minimum speed, no lane markings, or system not available. NOTE: Only on vehicles equipped with Detroit Assurance radar.
Malfunction Indicator Lamp
Indicates an emissions-related fault. See the engine operation manual for details.
No Charge
Indicates the alternator is not properly powering the electrical system.
Optimized Idle
Indicates optimized idle is enabled.
Outside Normal Ride Height
Indicates the current rear suspension height is not at the normal ride height. This light will turn off once the vehicle returns to normal ride height.
Roll Stability
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.
Stability Event
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.
Start Blocked
Indicates that the system is preventing the starter from cranking. This can occur when the ignition switch is turned to START before the gauge sweep has completed, or if the starter has overheated. NOTE: Illumination of the Start Blocked lamp does not indicate a problem with the starter. Turn the ignition switch back to ON, wait for the lamp to go out, then turn the ignition switch to START again.
Trailer ABS
Momentary illumination indicates the trailer ABS is engaged. Solid illumination indicates a problem with the trailer ABS. Repair the ABS immediately to ensure full braking capability
Transmission Overheat Warning
The transmission overheat indicator illuminates when the temperature of the transmission fluid goes above the preset level set by the transmission manufacturer.
Vehicle ABS
Momentary illumination indicates the vehicle ABS is engaged. Solid illumination indicates a problem with the vehicle ABS. Repair the ABS immediately to ensure full braking capability.
Wait To Start
Indicates that the system is preventing the starter from cranking. This can occur when the ignition switch is turned to START before the gauge sweep has completed, or if the starter has overheated. Turn the ignition switch back to ON, wait for the lamp to go out, then turn the ignition switch to START again.
Water in Fuel
Indicates the fuel may contain water. Drain any water collected in the fuel/water separators.
Wheel Spin
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.
Information Indicators (Green)
Cruise Control
Indicates the cruise control is enabled.
Economy Mode Indicator
The economy mode indicator displays an E when the driver changes the transmission mode to economy.
Engine Brake
Indicates the engine brake is enabled.
Left Turn Signal
Flashing indicates the outside left-turn signal lights are activated.
Right Turn Signal
Flashing indicates the outside right-turn signal lights are activated.
Service Transmission Indicator
The service transmission indicator activates when the transmission requires service. For example the transmission oil or filter may need to be changed. When the service transmission indicator illuminates, refer to the Allison Operator’s Manual or contact customer support at Allison Transmission to determine the specific cause activating the indicator.
Information Indicators (Blue)
High Beam Headlights Indicator
Indicates the high-beam headlights are on.