You might be surprised to learn that your Audi A5’s dashboard warning lights are more than just a nuisance – they’re a sophisticated system designed to predict and respond to potential hazards. From the pre-sense system that anticipates accidents to alerts for everything from airbag malfunctions to transmission issues, these lights are your first line of defense against compromised safety and performance.
Quick Navigation
Safety and Warning Systems
Pre-Sense Warning Light
Audi’s pre-sense system is a combination of safety features that predict and respond to potential hazards. If a warning triangle containing an exclamation mark appears on your dashboard, accompanied by a warning tone, it’s your cue to take immediate action to avoid an impending incident.
Airbag Warning Light
Additionally, you should be aware of other warning lights in this category, such as the airbag warning light.
ESC Warning Light
Electronic Stability Control (ESC) warning light.
Brake Wear Warning Light
and brake wear warning light, which indicate malfunctions in your vehicle’s safety systems.
Engine Malfunction Warning Lights
Engine Control Warning Light
You’ll see the engine control warning light if there’s a malfunction in the engine control system. Restart the engine or have it checked with diagnostics equipment to identify the issue.
Clutch Malfunction Warning Light
The clutch malfunction warning light indicates a problem with the clutch; adapt your driving style and contact service to avoid heavy load on the clutch.
Stem Warning Light
If you notice the stem warning light, drive to an Audi service center immediately, as there’s a malfunction in the engine start system.
Electrical System Failure Alerts
Battery Warning Light
A battery warning light indicates a fault with the generator/alternator or electrical charge system. This could be due to an electrical surge or battery drain.
Warning messages may appear, indicating an electrical system malfunction, that the vehicle battery has been disconnected from the electrical system, or that the battery is discharging. The warning light may remain on until the vehicle is serviced or the battery is recharged.
Transmission and Drivetrain Issues
All-Wheel Drive Warning Light
Keep an eye out for warning lights, such as the all-wheel drive malfunction.
Sport Differential Warning Light
or sport differential malfunction warnings, which may indicate a problem with your drivetrain.
Brake System Warning Lights
Brake Warning Light
If the brake warning light illuminates as a circle with an exclamation mark symbol or as BRAKE text, it may indicate low brake fluid levels or a malfunction in the brake booster.
ABS Warning Light
In some cases, this light may also indicate a fault with the ABS.
ESC Braking Warning Light
ESC, and braking distribution.
Airbag and Restraint System Alerts
Airbag Warning Light
As a vital safety feature, the airbag warning light will illuminate on your dashboard if there’s a malfunction in the safety restraint system. You’ll see a red or yellow warning triangle containing an exclamation mark, accompanied by a warning tone.
Adaptive Cruise Control Warnings
Adaptive Cruise Control Warning Light
If you see a warning light or message indicating a cruise control malfunction, disengage the system and take control of the vehicle.
Speed Limiter Warning Light
You may also receive speed limiter alerts if the system detects a speed limit on the road you’re driving on.
Electronic Stability Control Alerts
ESC Warning Light
If the ESC system malfunctions, a warning light will illuminate on your dashboard.
Engine Oil and Coolant Warnings
Engine Oil Warning Light
Engine Oil Warning: If your engine oil level is low, your engine may be at risk. Check your oil levels regularly and top up as needed.
Coolant Temperature Warning Light
Coolant Temperature Warning: If your engine coolant temperature is too high, it can cause engine damage. Pull over and turn off your engine to prevent further damage.
Tyre Pressure Monitoring System
Tyre Pressure Warning Light
If your tyres are underinflated, you’ll receive a warning on your dashboard, indicating which tyre needs attention.
Headlight and Lighting Issues
Headlight Range Control Warning Light
Headlight range control malfunction: A fault in the system can cause glare for other drivers.
Adaptive Headlight Warning Light
Adaptive headlights malfunction: Although the headlights will still function, a fault is indicated.
Light/Rain Sensor Warning Light
Light/rain sensor malfunction: For safety reasons, headlights are set to low beam only.
Parking Brake and Hill Descent
Parking Brake Warning Light
If you notice any unusual warning lights or messages, have your parking brake system checked by a professional.
Hill Descent Warning Light
The hill descent assist feature helps you navigate steep inclines by regulating your speed and maintaining traction.
Infotainment and Navigation Alerts
Infotainment System Warning Light
When using your Audi A5’s infotainment system, you may encounter alerts that require your attention.
Navigation System Warning Light
If your navigation system detects an invalid or blocked route, it will alert you and suggest an alternative route.
Vehicle System Malfunction Alerts
System Malfunction Warning Light
These alerts can appear as warning lights, sounds, or messages on your dashboard, indicating problems with your vehicle’s systems.
Key and Remote Control Warnings
Key Fob Battery Warning Light
Key fob battery warning: The battery in your key fob needs replacement.
Key Not Detected Warning Light
Key not detected warning light: Your key has been removed from the vehicle, and you can’t switch on the ignition or start the engine.
Additional Warning Lights
Glow Plug Warning Light (Diesel Models)
This yellow coil symbol appears in diesel models when there’s an issue with the pre-heating system. It typically illuminates during cold starts but should turn off once the engine warms up. Continuous illumination indicates faulty glow plugs that need replacement to ensure proper cold-weather starting.
DPF Warning Light (Diesel Models)
The diesel particulate filter warning light appears when the filter becomes clogged. The system may attempt automatic regeneration, but if the light stays on, extended highway driving is required to burn off accumulated soot. Ignoring this warning can lead to reduced performance and fuel economy.
AdBlue Warning Light (Diesel Models)
This blue warning indicates low levels of Diesel Exhaust Fluid (DEF) in vehicles with selective catalytic reduction systems. You’ll typically have about 1,500 miles before the system limits engine performance. Refill the DEF tank promptly to maintain emissions compliance.
Door Ajar Warning Light
This red vehicle outline with open door symbol appears when any door, hood or trunk isn’t properly closed while driving. It serves as an important safety reminder to secure all openings before proceeding.
Washer Fluid Warning Light
This yellow windshield symbol illuminates when washer fluid levels are low. During winter months, use a fluid with antifreeze properties to prevent freezing in the reservoir and lines.
Fuel Cap Warning Light
This yellow gas pump symbol appears if the fuel filler cap is loose, missing or not properly sealed. A loose cap can trigger the check engine light and affect emissions system performance.
Service Due Indicator Light
This wrench symbol appears when scheduled maintenance is required. The display will indicate whether minor (A) or major (B) service is needed based on your vehicle’s mileage and condition monitoring.
Start/Stop System Warning Light
This amber “A” with circular arrow symbol indicates the automatic start/stop system is unavailable. Common causes include low battery charge, extreme temperatures, or high electrical demand from vehicle systems.
Advanced Driver Assistance Warnings
Lane Departure Warning Light
This amber lane symbol flashes when the system detects unintentional lane drift without turn signal use. It may be accompanied by steering wheel vibration. The system automatically deactivates below 40 mph or when turn signals are used.
Blind Spot Monitoring Warning Light
This yellow triangle in the side mirror appears when a vehicle is detected in your blind spot. The light intensifies if you activate the turn signal in that direction. System may be unavailable in heavy rain or when sensors are obstructed.
Hybrid/Electric System Alerts (for Hybrid Models)
Hybrid System Warning Light
This red triangle with exclamation point indicates a serious fault in the high-voltage system. The vehicle may enter limp mode. Immediately reduce speed and seek professional assistance – the high-voltage system carries dangerous current levels.
EV System Warning Light
For plug-in hybrid models, this warning indicates issues with the electric drive system. The vehicle may restrict or disable electric-only operation until the fault is resolved. Common causes include battery cooling system faults or charging circuit problems.
Lighting System Warnings
Automatic High Beam Warning Light
This blue headlight symbol with “A” indicates a fault in the automatic high beam assist system. The system reverts to manual high beam control until repaired. May be caused by dirty windshield sensors or electrical faults.
Rear Fog Light Indicator
This green light simply confirms activated rear fog lights. Remember to turn them off when not needed in poor visibility, as they can blind following drivers and are illegal for normal use in many areas.
Climate Control Warnings
AC System Warning Light
This snowflake symbol indicates refrigerant pressure issues or compressor faults. The air conditioning may not cool properly. Common causes include low refrigerant charge, faulty pressure sensors, or compressor clutch failure.
Cabin Air Filter Warning Light
This icon appears when the cabin air filter needs replacement. A clogged filter reduces HVAC efficiency and can allow pollutants into the cabin. Typically illuminates at scheduled maintenance intervals.
Additional Safety Indicators
Seat Belt Warning Light
This red person-with-seatbelt symbol flashes with a chime when seatbelts are unbuckled while driving. The warning intensifies at higher speeds. Some models provide individual seat warnings.
Child Seat Detection Warning Light
For vehicles with advanced occupant detection systems, this light indicates potential issues with child seat installation or weight sensor calibration in front passenger seats.
Remember that warning lights follow a color-coded system:
- Red lights indicate urgent safety issues requiring immediate attention
- Yellow/amber lights signify important warnings that need prompt service
- Green/blue lights are informational indicators showing active systems
Always consult your owner’s manual when any warning light appears, and seek professional diagnosis for persistent warnings to maintain your Audi A5’s performance and safety systems.
