Safety systems

Problem Possible causes/consequences and Solutions
(Canada only) (USA only)

The red brake system (Canada only)

The red brake system warning lamp comes on while the engine is running. A warning tone also sounds.

There is not enough brake fluid in the brake fluid reservoir. Risk of accident

There is not enough brake fluid in the brake fluid reservoir.
vehicle safely as soon as possible, paying Pull over and stop the vehicle safely as soon as possible, paying attention to road and traffic conditions. Do not continue driving under any circumstances.
Consult a qualified Engage the parking brake.
specialist workshop immediately. Consult a qualified specialist workshop immediately.
display messages in the multifunction Observe the additional display messages in the multifunction display.
Do not add brake fluid. This will not rectify the malfunction.

WARNING
Driving with the brake warning lamp illuminated can result in an accident. Have your brake system checked immediately if the brake warning lamp stays on. Do not add brake fluid before checking the brake system.
Overfilling the brake fluid reservoir can result in spilling brake fluid on hot engine parts and the brake fluid catching fire. You can be seriously burned.

Problem Possible causes/consequences and Solutions
yellow ABS warning

The yellow ABS warning lamp is lit while the engine is running.

ABS (Anti-lock Brake System) is deactivated due to a malfunction. Risk of accident

ABS (Anti-lock Brake System) is deactivated due to a malfunction.

BAS (Brake Assist), BAS PLUS, ESP® (Electronic Stability Program), PRE-SAFE® Brake, the HOLD function and hill start assist are therefore also deactivated, for example.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.
ATTENTION ASSIST is deactivated.
display messages in the multifunction Observe the additional display messages in the multifunction display.
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other systems, such as the navigation system or the automatic transmission, will not be available.

yellow ABS warning

The yellow ABS warning lamp is lit while the engine is running.

ABS is temporarily unavailable. BAS, BAS PLUS, ESP®, EBD Risk of accident

ABS is temporarily unavailable. BAS, BAS PLUS, ESP®, EBD (electronic brake force distribution), PRE-SAFE® Brake, the HOLD function, hill start assist are therefore also deactivated, for example.
Self diagnosis is not yet complete or the on-board voltage may be insufficient, for example.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.
ATTENTION ASSIST is deactivated.
distance making slight steering Carefully drive a suitable distance making slight steering movements at a speed above 12 mph (20 km/h).
The functions mentioned above are available again when the warning lamp goes out.
If the warning lamp is still on:
display messages in the multifunction Observe the additional display messages in the multifunction display.
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.

yellow ABS warning

The yellow ABS warning lamp is lit while the engine is running. A warning tone also sounds.

EBD is faulty. Therefore, ABS, BAS, BAS PLUS, ESP®, PRE-SAFE®, Risk of accident

EBD is faulty. Therefore, ABS, BAS, BAS PLUS, ESP®, PRE-SAFE®, PRE-SAFE® Brake, the HOLD function and hill start assist are unavailable, for example.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.
ATTENTION ASSIST is deactivated.
display messages in the multifunction Observe the additional display messages in the multifunction display.
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.

(Canada only) (USA only)

(Canada only)

The red brake warning

The red brake warning lamp, the yellow ESP® and ESP® OFF warning lamps and the yellow ABS warning lamp are lit while the engine is running.

ABS and ESP® are faulty. Therefore, BAS, BAS PLUS, EBD, PRESAFE Risk of accident

ABS and ESP® are faulty. Therefore, BAS, BAS PLUS, EBD, PRESAFE ® Brake, the HOLD function and hill start assist, for example, are unavailable due to a malfunction.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.
ATTENTION ASSIST is deactivated.
display messages in the multifunction Observe the additional display messages in the multifunction display.
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.

yellow ESP®

The yellow ESP® warning lamp flashes while the vehicle is in motion.

ESP® or traction control has intervened because there is a risk of Risk of accident

ESP® or traction control has intervened because there is a risk of skidding or at least one wheel has started to spin.
Cruise control or DISTRONIC PLUS is deactivated.
accelerator pedal as far as necessary when Only depress the accelerator pedal as far as necessary when pulling away.
pedal while the vehicle is in motion. Ease off the accelerator pedal while the vehicle is in motion.
suit the road and weather conditions. Adapt your driving style to suit the road and weather conditions.
Do not deactivate ESP®.

yellow ESP® OFF

The yellow ESP® OFF warning lamp is lit while the engine is running.

ESP® is deactivated. ESP® will not stabilize the vehicle if it starts Risk of accident

ESP® is deactivated. ESP® will not stabilize the vehicle if it starts to skid or if a wheel starts to spin.
Adapt your driving style to Reactivate ESP®.
suit the road and weather conditions. Adapt your driving style to suit the road and weather conditions.
If ESP® cannot be activated:
qualified specialist workshop. Have ESP® checked at a qualified specialist workshop.

vehicles only:

AMG vehicles only:

The yellow SPORT handling mode warning lamp is lit while the engine is running.

SPORT handling mode is activated. ESP® only stabilizes the vehicle Risk of accident

SPORT handling mode is activated. ESP® only stabilizes the vehicle in extreme situations. ESP® intervention may not be able to provide sufficient assistance in such situations and the vehicle may start to skid.
If ESP® cannot be activated: Reactivate ESP®.
If ESP® cannot be activated:
qualified specialist workshop. Have ESP® checked at a qualified specialist workshop.

yellow ESP® and

The yellow ESP® and ESP® OFF warning lamps are lit while the engine is running.

ESP®, BAS, BAS PLUS, PRE-SAFE® Brake, the HOLD function and Risk of accident

ESP®, BAS, BAS PLUS, PRE-SAFE® Brake, the HOLD function and hill start assist are not available due to a malfunction. ESP® will not stabilize the vehicle if it starts to skid or if a wheel starts to spin.
The brake system continues to function normally, but without the functions listed above.
ATTENTION ASSIST is deactivated.
display messages in the multifunction Observe the additional display messages in the multifunction display.
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.

yellow ESP® and

The yellow ESP® and ESP® OFF warning lamps are lit while the engine is running.

ESP®, BAS, the HOLD function and hill start assist are temporarily Risk of accident

ESP®, BAS, the HOLD function and hill start assist are temporarily unavailable.
BAS PLUS and PRE-SAFE® Brake may also have failed.
ESP® will not stabilize the vehicle if it starts to skid or if a wheel starts to spin.
Self diagnosis is not yet complete.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.
ATTENTION ASSIST is deactivated.
distance making slight steering Carefully drive a suitable distance making slight steering movements at a speed above 12 mph (20 km/h).
The functions mentioned above are available again when the warning lamp goes out.
If the warning lamp is still on:
display messages in the multifunction Observe the additional display messages in the multifunction display.
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.

(Canada only) (USA only)

The red brake system (Canada only)

The red brake system warning lamp comes on while the vehicle is moving. A warning tone also sounds.

You are driving with the parking brake applied.
The warning lamp goes out and the warning tone ceases. Release the parking brake
The warning lamp goes out and the warning tone ceases.
SRS warning

The red SRS warning lamp is lit while the engine is running.

The restraint systems are malfunctioning. The air bags or ETDs Risk of injury

The restraint systems are malfunctioning. The air bags or ETDs may either be triggered unintentionally or, in the event of an accident, not be triggered at all.
Visit a qualified Drive on carefully.
specialist workshop immediately. Visit a qualified specialist workshop immediately.

WARNING
In the event a malfunction of the SRS is indicated as outlined above, the SRS may not be operational.
For your safety, we strongly recommend that you contact an authorized Mercedes-Benz Center immediately to have the system checked. Otherwise the SRS may not be activated when needed in an accident, which could result in serious or fatal injury, or it might deploy unexpectedly and unnecessarily which could also result in injury.

    See also:

    Brake fluid
    WARNING Over a period of time, the brake fluid absorbs moisture from the air; this lowers its boiling point. If the boiling point of the brake fluid is too low, vapor pockets may form in t ...

    Using the SmartKey
    – Turn the SmartKey to position 0 in the ignition lock and remove it. The immobilizer is activated. If you turn off the engine with the SmartKey and then remove it from the ignition lock ...

    Limited braking performance on salt treated roads
    WARNING The layer of salt on the brake discs and the brake pads/linings may cause a delay in the braking effect, resulting in a significantly longer braking distance, which could lead to an ...