Mercedes-Benz Warning Lights | Complete Guide with Images

Your Mercedes-Benz has a range of complex safety systems relying on sensors and safety mechanisms to ensure that your vehicle is working at its optimum performance while ensuring full protection for other road users and passengers. From time to time warning light appears on your dashboard which can seem daunting, especially if you are unsure what to do.

We have created this simple guide to help you understand each of the more common warning light that may appear on your new or used Mercedes-Benz vehicle. It is important that you know how to respond to each warning light to reduce any additional damage to your vehicle and to ensure that your vehicle is safe. If you are unsure how to carry out an action or repair on your vehicle our Mercedes-Benz trained experts know your Mercedes-Benz better than anyone.

Red warning lights mean you should stop the car as soon as it is safe.

Yellow warning lights mean that action is required.

Green warning lights are for information only.


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Worried about your Volkswagen? Checkout our complete guide to Volkswagen Warning Lights.

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Red Warning Lights

Brake System

Check if the handbrake is applied. If so, release the handbrake. If the light disappears you can continue to drive as normal.

If the light stays on check your brake fluid level and fill up accordingly.*

If the light disappears this is a normal function. If the light remains on contact Roadside Assistance.

Engine Cooling System

Switch off the engine immediately.

Wait until the engine has cooled down, make sure the air supply to the radiator has not been inpaired. Avoid high loads on the engine and drive to the nearest authorised repairer ensuring the coolant temperature remains below the red marking.

Caution - the cooling system is a pressurised system. Allow the car to cool down before adding coolant to prevent injury. We advise having the coolant topped up by a professional at an authorised repairer.

If the light remains on contact Roadside Assistance.

Engine Oil Pressure

Switch off the engine immediately. Do not restart.

Check the oil level. If the oil level is ok contact Roadside Assistance.

If the oil level is low fill up accordingly* Start the engine, and let it run for five seconds, then switch off engine.

If light is still on contact Roadside Assistance.

Power Steering System

This indicated an issue with the power steering system. If safe to do so, continue driving to your nearest Mercedes-Benz authorised repairer.

If the steering feels unsafe or jeopardising the vehicles safety, please pull over when safe to do so and contact Roadside Assistance.

Airbag and Seatbelt System

There is a fault in the airbag or seatbelt system. If the wanring lamp doesn't light up when the ignition is turned on or if it lights up continiously/repeatedly during a journey, consult an authorised repairer immediately.

Vehicle Charging System

There is an alternator or electrical system fault in the vehicle.

Switch off all consumer electrical products that may drain the battery further.

Leave the engine running a few minutes or drive for 10-15 minutes to allow for battery regeneration. If you cannot start the engine contact Roadside Assistance

Seatbelt Buckles

Check that the driver and front passenger has their seatbelt fastened properly. If the light disappears, this is a normal function. 

If the light does not disappear contact an authorised repairer.​

Recharge AdBlue (Red)

Stop the car as soon as it is safe to do so.

The red warning light appears when there is no AdBlue range left; once this happens the car will not restart once the ignition is turned off.

The system will need a full top-up before the car can be restarted.*​

Bonnet

Check that the bonnet is closed properly. If the light disappears this is a normal function.

If the light does not disappear contact an authorised repairer.​

Boot Lid

Check the boot lid is closed properly. If the light disappears this is a normal function.

If the light does not disappear contact an authorised repairer.

Mercedes SOS

At least one of the main functions of the Mercedes Me connect system or SOS emergency call system have malfunctioned.

Please consult your nearest Mercedes-Benz dealership.


​Yellow Warning Lights

Emissions Control Light

This indicated an issue with the engine, exhaust system or fuel system.

Remove the key for 30 seconds then reinsert and start the engine. If the light disappears, the problem is rectified. Visit an authorised repairer for a check.

If the light does return and the power is down contact Roadside Assistance. If the light returns and the power is not down, take extra care and drive to an authorised repairer.

Flashing light: If the vehicle power is down and the vehicle is vibrating contact Roadside Assistance. If the vehicle power is not down and is not vibrating take caution and drive to an authorised repairer. If this is not possible call Roadside Assistance.

Attention Assist

This will illuminate when fatigue or an lack of concentration has been detected from the driver. If necessary, take a break.

If the system continues to illuminate, consult a qualified workshop/repairer.​

Parking Sensor Malfunction

The park assist PARKTRONIC system has been deactivated due either signal interference, dirty sensors or a malfunction.

Turn the vehicle on and off as well as ensure the sensors are clean. If the problem persists, contact a qualified repairer.

Engine Management Warning Light (Diesel Engines Only)

If the light appears when the ignition is switched on, this is a normal function (to appear for a few seconds).

If the light appears whilst the engine is running drive slowly and carefully to an authorised repairer immediately due to engine management fault.

Engine Oil Level

Permanent light: This will indicate the oil level has either dropped or exceeded the recommend levels.

If oil level is below the recommend level, top-up the oil level above the minimum level.

If oil level is above the maximum level, consult a qualified workshop as excess engine oil can damage the engine.

This light may also highlight the oil level sensor has malfunctioned. If the oil level is at the correct level, ​please consult a qualified specialist workshop.

Anti-Lock Brake System

This is your Anti-Lock Braking System light. If this light illuminates, it will indicate the safety systems are currently not available which result in longer emergency braking distances.

Drive carefully to an authorised repairer.

Electronic Stability Programme

Permanent light: Switch off the ignition and then restart. If the light is still on, drive carefully to an authorised repairer.

Flashing light: This is a normal operating feature. No action is required.

Tyre Pressure Monitoring

This is your tyre pressure monitoring light.

This will typically indicate low tyre pressures or a missing/faulty wheel sensor.

If the tyre pressures are ok and the light is still on, drive carefully to an authorised repairer to have the system examined.

Power Steering System

If your battery has been disconnected or discharged or if your vehicle has been jump started - turn your steering wheel fully to the left, then fully to the right and drive a short distance at 20-30km/hour. If the light disappears visit an authorised repairer at your convenience for a check. If the light does not disappear, drive carefully to an authorised repairer if safe to do so. 

If this is not possible contact Roadside Assistance

Brake Pad Monitoring

This is your brake pad warning light.

Your brake pads have reached their wear limit and braking may be limited. Contact an authorised repairer to check the condition of your brake pads.

Airbag and Seatbelt System

Drive carefully to an authorised repairer immediately as there is a fault in the airbag or seatbelt system.

The system may fail to trigger in an accident if you do not get the fault rectified. 

Automatic Gearbox

This is your gearbox malfunction light.   A message may appear – follow the instructions and drive to an authorised repairerimmediately as long as it is safe to do so.  If this is not possible contact Roadside Assistance.

If the message asks you to stop the vehicle and select P, contact Roadside Assistance.

Smart Key

The warning light will indicate a number of issues with the smart key including the battery discharging, key not being detected and can also be to warn you to take your key when leaving the vehicle (a warning may also sound).

Consult a qualified authorised repair.

Suspension Dampers

Malfunction has been detected with the suspension system which may impact vehicle handing characteristics.

Drive in an appropriate manner below 50 mph to the nearest qualified workshop.

Contact an authorised repairer.

Active Brake Assist

Active break assist consists of the following functions, distance warning function, autonomous braking function, situation dependent braking assist and evasive steering assist. If this warning light appears, all or some of the safety systems may not be functioning.

If all sensors are clear and free of dirt, please consult a qualified repairer.

Downhill Speed Regulation

This includes the downhill speed system regulation is in use or is malfunctioning. If the system is in use, the maximum speed is 25 mph and the light will flash if the speed is exceeded.

Contact an authorised repairer.

Headlight Range Control

There is a headlight range control system fault.

Contact an authorised repairer.​

Low/High Beam

This indicated whether the headlights are on low or high beam. If the headlights are set to automatic, they light will automatically appear when dark.

Contact an authorised repairer.

Fuel

The fuel level has dropped into the reserve. Please refuel as soon as possible.

If you do have fuel, this could indicate the fuel cap is loose.

Active Lane Assist

This light will appear when lane assist is switched on and road markings cannot be detected.

If this light is accompanied with a “system fault” message, contact an authorised repairer.

Hold Handbrake System

The hold function has been activated. This is normally activated by pressing hard on the brake while the transmission is in drive mode. To disengage hold, press the accelerator pedal.

If this continues to illuminate, please seek an authorised repairer.

Windscreen Washer Fluid Level

The windscreen washer fluid reservoir needs filling.

Top up the fluid for the windscreen washer.

Refer to the owner’s manual.

Rear Fog Lights

​This warning light will appear when the rear fog lights are switched on.

Only operate the rear fog lights in foggy conditions to avoid dazzling other drivers.​

Low Fuel Level

The fuel in the fuel tank has reached the reserve level.

Drive to a filling station without delay and refill with the correct fuel type.

Cruise Control

The cruise control light will appear when the cruise control system is activated.

This is a normal operating feature of the system.

Refer to the owner’s manual or contact your nearest authorised repairer for an explanation of the operation of the system.​

Headlight Warning

You're leaving your vehicle with the headlights still on. Turn the light switch position to off or auto.

If this doesn't result in the light turning off, the lighting system may be fault. Please contact an authorised repairer.


​Driving Modes

Economy and Comfort Driving Mode

The economy and comfort drive program provides higher levels of economy and comfort by reducing the engine idol speed as well reducing over revving of the engine while driving.

This mode is particular well suited to driving in snowy, icy or wet conditions.​

Sport Driving Mode

The sport drive program offers stability but with a sporty set-up allowing for a more enthusiastic driving style​.

Ideal for dry driving conditions.

Sport+ Driving Mode

The vehicles own understeer and oversteer ​characteristics are accentuated allowing for more active and sporty driving.

Ideal for dry roads with good driving conditions.


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*Refer to owner’s manual or seek professional assistance.

The information on warning lights on this page does not apply to electric cars. Please consult your owner's manual.