Warnings, Indicators, and Messages
Warning and indicator lights (telltales) with icon symbols are displayed on the physical dashboard and on ICU screens. The positions of the telltales and warnings vary, but most telltale symbols are standard. See the below tables for a listing of different warnings and telltales in addition to messages and popup screens.
The colors of telltales and warnings indicate the hazard level: red (warning), amber (caution), green and blue (active status), grey (passive status), white (informational). Blue is currently used to indicate an active phone call, that a software download is available, and that utility lamps and high beams are on.
Important: Depending upon local jurisdictional emissions guidelines, vehicles and/or engines that are domiciled outside of the U.S. and Canada may not be compliant with EPA10 or GHG21 regulations. Noncompliant vehicles may not be equipped with all of the telltales shown in the below tables.
Engine-Related Indicators
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Warnings, Indicators, and Messages — Engine System |
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Telltale |
Color |
Description |
Related Messages |
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Red |
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. |
Various |
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Red |
Engine Oil Level Warning |
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Red |
Low Engine Oil Pressure |
Indicates the engine oil pressure is below the minimum allowable pressure. |
ICUC Warning |
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Red |
Engine Oil Temperature Warning |
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Red |
Low Coolant Level |
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Red |
High Coolant Temperature |
Indicates the coolant temperature is above the maximum allowable temperature. |
ICUC Warning |
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Amber |
Check Engine¹ |
Indicates an engine condition (low oil pressure, low coolant level, high coolant temperature, high DPF soot level, uncontrolled DPF regeneration, or battery voltage 11.9 volts or less) that requires correction. Correct the condition as soon as possible. If the condition worsens, the STOP engine lamp will illuminate. |
Various |
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Amber |
Engine Malfunction Indicator Lamp (MIL)¹ |
A steadily illuminated amber MIL lamp indicates an engine fault that effects emissions. |
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Amber |
Engine Malfunction Indicator Lamp (MIL)¹ |
Alternate Engine Malfunction Indicator lamp. A steadily illuminated amber MIL lamp indicates an engine fault that effects emissions. |
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Amber |
Engine Oil Level Caution |
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Amber |
Engine Oil Pressure Caution |
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Amber |
Low Coolant Level Caution |
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Amber |
High Coolant Temperature Caution |
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Amber |
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. Display of the Start Blocked screen does not indicate a problem with the starter. Turn the ignition switch back to ON, wait for the message to turn off, then turn the ignition switch to START again. |
ICUC Notice |
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Amber |
Start Blocked |
Alternative Telltale for Start Blocked. |
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Green |
Start Engine |
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Green |
Optimized Idle Active |
Indicates optimized idle is active. |
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Transmission-Related Indicators
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Warnings, Indicators, and Messages — Transmission |
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Telltale |
Color |
Description |
Related Messages |
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Red |
Transmission Fluid Level Warning |
Indicates low transmission fluid level. Safely bring the vehicle to a stop as soon as possible. |
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Amber |
Caution Check Transmission |
Indicates an undesirable transmission condition. |
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Amber |
Low Transmission Fluid Level Caution |
Indicates low transmission fluid level. |
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Amber |
High Transmission Temperature |
Indicates transmission is overheating. |
ICUC Caution |
Brake-Related Indicators
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Warnings, Indicators, and Messages — Brakes |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Red |
Low Brake Air Pressure (EPA10 and Newer) |
Indicates air pressure in the primary or secondary reservoir has dropped below approximately 70 psi (483 kPa). |
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Red |
Low Brake Air Pressure (EPA10 and Newer) |
Alternate low brake air pressure telltale. Indicates air pressure in the primary or secondary reservoir has dropped below approximately 70 psi (483 kPa). |
 ICUC Warning |
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Red |
Parking Brake Engaged (EPA10 and Newer) |
Indicates the parking brake is engaged. |
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Red |
Parking Brake Engaged (EPA10 and Newer) |
Alternative icon indicating the parking brake is engaged. |
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Amber |
Hill Start Aid Disengaged |
A blinking telltale indicates hill start aid is inactive. A solid telltale indicates a fault with the system. |
To turn on HSA, press the HSA OFF switch again or restart the vehicle. |
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Amber |
Winch Brake Caution |
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Amber |
Work Brake Caution |
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Green |
Descent Control Mode Engaged |
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Green |
Engine Brake Engaged |
Indicates the engine brake is enabled. |
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Driving-Safety-Related Indicators
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Warnings, Indicators, and Messages — Driving Safety |
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Telltale |
Color |
Description |
Related Messages |
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Amber |
Electronic Stability Control (ESC) Active |
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. |
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Amber |
Electronic Stability Program Off |
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Amber |
Tractor Anti-Lock Braking System (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. |
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Amber |
Trailer Anti-Lock Braking System (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. |
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Amber |
Active Brake Assist Active |
Indicates Active Brake Assist is engaged. |
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Amber |
Active Brake Assist Unavailable (GHG14 and newer) |
Indicates the Active Brake Assist system is not available. |
 ICUC Caution |
 ICC5 Telltale |
Amber |
Lane Departure Unavailable |
Indicates that lane departure warning is disabled due to minimum speed, lack of lane markings, or system not being available. Only on vehicles equipped with Detroit Assurance radar. |
|
 ICUC Telltale |
Amber |
Lane Departure Unavailable |
Indicates that lane departure warning is disabled due to minimum speed, lack of lane markings, or system not being available. Only on vehicles equipped with Detroit Assurance radar. |
 ICUC Caution |
 ICC5 Telltale |
Amber |
Adaptive Cruise Control Not Available |
Indicates that Adaptive Cruise Control (ACC) is not available Only on vehicles equipped with a radar-based collision warning and mitigation system (CWS/CMS). |
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 ICUC Telltale |
Amber |
Adaptive Cruise Control Not Available |
Indicates that Adaptive Cruise Control (ACC) is not available Only on vehicles equipped with a radar-based collision warning and mitigation system (CWS/CMS). |
 ICUC Caution If ACC is not available, Active Lane Assist (ALA) will not be available. |
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Amber |
IPPC Error |
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Green |
Adaptive Cruise Control Active |
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Red |
Adaptive Power Steering (APS) Error |
An error with APS deactivates Active Lane Assist (ALA). |
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Blue |
Lane Keep Assist (LKA) Active |
LKA is a component of Active Lane Assist (ALA) along with Lane Departure Protection (LDP). If Adaptive Cruise Control (ACC) is not available, ALA will not be available. |
This is also the Switch icon |
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Grey |
Lane Keep Assist (LKA) on Standby |
When LKA is OFF there is no steering wheel icon |
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Amber |
Gear Teach Mode in Progress |
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Green |
AERO active |
Indicates that aerodynamic height control (AERO) is active. |
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Suspension-Related Indicators
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Warnings, Indicators, and Messages — Suspension |
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Telltale |
Color |
Description |
Related Messages |
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Amber |
Suspension Higher than Normal Ride Height / Axle Lifted |
Indicates the current rear suspension height is above the normal ride height. |
ICUC Caution |
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Amber |
Suspension Lower Than Normal Ride Height / Axle Dropped |
Indicates the current rear suspension height is below the normal ride height. |
 ICUC Caution |
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Amber |
Suspension Height |
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Amber |
Electronically Controlled Air Suspension (ECAS) Error |
Indicates Electronically Controlled Air Suspension (ECAS) active fault. |
 ICUC Caution |
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Amber |
Load Transfer |
Indicates the ECAS system is applying the maximum available vehicle load on the drive axle up to the maximum gross axle weight rating (GAWR). |
 ICUC Caution |
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Amber |
5th Wheel Adjust |
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Battery-Related Indicators
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Warnings, Indicators, and Messages — Battery |
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Telltale |
Color |
Description |
Related Messages |
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Red |
Battery Critical |
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Red |
Battery Failure |
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Amber |
Battery Failure |
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Tire-Related Indicators
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Warnings, Indicators, and Messages — Tires and ATC |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Red |
Low Tire Pressure Warning |
Indicates a notable loss of tire pressure in at least one tire. |
If a tire monitoring system is available, the tire(s) with low pressure will be highlighted red. |
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Amber |
Low Tire Pressure Warning |
Indicates low tire pressure in at least one tire. |
If a tire monitoring system is available, the tire(s) with low pressure will be highlighted amber. |
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Amber |
Automatic Traction Control (ATC) Active |
Flashing indicates a wheel spin event has been detected, and the ATC system is active. |
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Amber |
Automatic Traction Control (ATC) Deactivated |
Indicates the ATC SPIN button has been pressed to allow wheel slip. |
 ICUC Caution |
Fuel-Related Indicators
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Warnings, Indicators, and Messages — Fuel |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Amber |
Low Fuel |
Indicates low fuel level. Refill the main fuel tank. |
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Amber |
Water in Fuel Warning |
Indicates the fuel may contain water. Drain any water collected in the fuel/water separators. |
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Diesel Exhaust Fluid (DEF)- and Diesel Particulate Filter (DPF)-Related Indicators
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Warnings, Indicators, and Messages — DEF and DPF |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Red |
Diesel Particulate Filter Critical |
Indicates a parked regen is required immediately. |
 ICUC Warning |
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Amber |
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. |
 ICUC Caution |
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Amber |
Diesel Particulate Filter Inhibited |
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Green |
Diesel Particulate Filter Regeneration in Progress |
Indicates a regen is in progress. |
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Amber |
High Exhaust System Temperature (HEST)* |
Slow (10-second) flashing indicates a regeneration (regen) is in progress. When the HEST lamp is illuminated, do not park the vehicle near objects that can be harmed by high temperatures or flammable materials. Solid illumination indicates high exhaust temperatures at the outlet of the tail pipe when speed is below 5 mph (8 km/h). |
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Amber |
Low Diesel Exhaust Fluid |
Indicates low diesel exhaust fluid. Fill the DEF tank. |
See Chapter 14 for an explanation of the after treatment system (ATS) warnings, and actions required to avoid further engine protection steps. |
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Amber |
Low Diesel Exhaust Fluid |
Alternative icon to indicate Low Diesel Exhaust Fluid. Fill the DEF tank. |
See Chapter 14 for an explanation of the after treatment system (ATS) warnings, and actions required to avoid further engine protection steps. |
Lamp-Related Indicators
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Warnings, Indicators, and Messages — Lamps |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Green |
Right-Turn Indicator On |
Flashing indicates the outside right-turn signal lamps are activated. |
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Green |
Left-Turn Indicator On |
Flashing indicates the outside left-turn signal lamps are activated. |
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Blue |
High-Beams On |
Indicates the high-beam headlights are on. |
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Green |
Low-Beams On |
Indicates the low-beam headlights are on. |
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Blue |
Automatic High-Beams On |
Indicates the high-beam headlights have been set to automatic and are on. |
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Grey |
Automatic High-Beams Off |
Indicates the high-beam headlights have been set to automatic and are off. |
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Green |
Automatic Low-Beams On |
Indicates the low-beam headlights have been set to automatic and are on. |
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Grey |
Automatic Low-Beams Off |
Indicates the low-beam headlights have been set to automatic and are off. |
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Green |
Daytime Running Lamps On |
Indicates the daytime running lamps are on. |
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Blue |
Auxiliary Drive Lamps On |
Indicates the auxiliary drive lamps are on. |
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Blue |
Utility Lamps On |
Indicates the utility lamps are on. |
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Green |
Taillights / Marker Lamps On |
Indicates the taillights, aka marker lamps, are on. |
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Passenger-Safety-Related Indicators
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Warnings, Indicators, and Messages — Passenger Safety |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Red |
Unfastened Seat Belt |
On some vehicles, activates with an audible alert when the system detects that the parking brake is off and the driver seat belt is not fastened. On vehicles with a seat occupancy sensor, the seat being occupied, seat belt not fastened, and parking brake off will cause this warning to activate. On other vehicles, this lamp illuminates for 15 seconds when the ignition is first turned on. |
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Amber |
Supplemental Restraint System (SRS) Error |
Indicates a malfunction has occurred in the restraint system and restraint system components may be triggered unintentionally or may not deploy as intended during an accident. Have the restraint system checked and repaired immediately. |
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Weather-Related Indicators
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Warnings, Indicators, and Messages — Weather |
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Telltale |
Color |
Description |
Related Messages |
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White |
Snowflake |
Indicates ambient air temperature has dropped below 34°F (1°C). Pay attention to road conditions and watch for ice. |
ICUC Caution |
ICU-Application-Related Indicators
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Warnings, Indicators, and Messages — ICU Application |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Blue |
Active Phone Call |
Indicates a phone is connected to the ICU and a call is active. |
The phone screen in the infotainment section of the ICU will also show an active call, including the number being called and call length. |
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Blue |
Software Download Available |
Indicates a software download is available. For reasons of security and optimal vehicle functioning, software updates should be quickly installed. |
A pop-up message will also appear. |
Air Gauge-Related Indicators
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Warnings, Indicators, and Messages — Air Gauge |
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|---|---|---|---|---|
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Telltale |
Color |
Description |
Related Messages |
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Red |
Primary Air Warning |
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Red |
Secondary Air Warning |
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Red |
Application Air Warning |
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Amber |
Primary Air Caution |
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