Safety systems

Display messages Possible causes/consequences and Solutions
Risk of accident ABS (Anti-lock Braking System), ESP® (Electronic Stability Risk of accident

ABS (Anti-lock Braking System), ESP® (Electronic Stability Program), BAS (Brake Assist), the HOLD function and hill start assist are temporarily unavailable.
BAS PLUS and PRE-SAFE® Brake may also have failed.
In addition, the and, warning lamps light up in and the instrument cluster. warning lamps light up in the instrument cluster.
The self-diagnosis function might not be complete, for example.
ATTENTION ASSIST is deactivated.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.

suitable distance making slight steering Carefully drive a suitable distance making slight steering movements at a speed above 12 mph (20 km/h).
If the display message disappears, the functions mentioned above are available again.

If the display message continues to be displayed:
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.
ABS, ESP®, BAS, the HOLD function and hill start assist are Risk of accident

ABS, ESP®, BAS, the HOLD function and hill start assist are temporarily unavailable.
BAS PLUS and PRE-SAFE® Brake may also have failed.
In addition, the and, warning lamps light up in and the instrument cluster. warning lamps light up in the instrument cluster.
For example, the on-board voltage may be insufficient.
ATTENTION ASSIST is deactivated.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.

If the display message disappears, the functions mentioned Drive on carefully.
If the display message disappears, the functions mentioned above are available again.

If the display message continues to be displayed:
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident ABS, ESP®, BAS, the HOLD function and hill start assist are Risk of accident

ABS, ESP®, BAS, the HOLD function and hill start assist are unavailable due to a malfunction.
BAS PLUS and PRE-SAFE® Brake may also have failed.
The (Canada only), (USA only)/ , (Canada only), , and warning lamps in the and instrument cluster also light up. warning lamps in the instrument cluster also light up.
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.
Visit a qualified Drive on carefully.
specialist workshop immediately. Visit a qualified specialist workshop immediately.
Risk of accident 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.
In addition, the warning lamps light up in and the warning lamps light up in the instrument cluster.
The self-diagnosis function might not be complete, for example. ATTENTION ASSIST is deactivated.
The brake system continues to function normally, but without the functions listed above.
distance making slight steering Carefully drive a suitable distance making slight steering movements at a speed above 12 mph (20 km/h).
If the display message disappears, the functions mentioned above are available again.
If the display message continues to be displayed:
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident ESP®, BAS, the HOLD function and hill start assist are unavailable Risk of accident

ESP®, BAS, the HOLD function and hill start assist are unavailable due to a malfunction.
BAS PLUS and PRE-SAFE® Brake may also have failed.
In addition, the warning lamps light up in and the warning lamps light up in the instrument cluster.
ATTENTION ASSIST is deactivated.
The brake system continues to function normally, but without the functions listed above.
Visit a qualified Drive on carefully.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident EBD (electronic brake force distribution), ABS, ESP®, BAS, the Risk of accident

EBD (electronic brake force distribution), ABS, ESP®, BAS, the HOLD function and hill start assist are unavailable due to a malfunction.
BAS PLUS and PRE-SAFE® Brake may also have failed.
In addition, the and, warning lamps light up in and the instrument cluster and a warning tone sounds. warning lamps light up in the instrument cluster and a warning tone sounds.
ATTENTION ASSIST is deactivated.
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you brake hard, for example.
Visit a qualified Drive on carefully.
specialist workshop immediately. Visit a qualified specialist workshop immediately.
The brake pads/linings have reached their wear limit. The brake pads/linings have reached their wear limit.
specialist workshop. Visit a qualified specialist workshop.
You are driving with the parking brake applied. A warning tone also You are driving with the parking brake applied. A warning tone also sounds.
Release the parking brake.
A malfunction has occurred while the HOLD function or A malfunction has occurred while the HOLD function or DISTRONIC PLUS is active.
A tone may also sound at regular intervals. The tone becomes louder if you attempt to lock the vehicle.
You cannot start the engine.
traffic situation, immediately depress the Paying attention to the traffic situation, immediately depress the brake pedal firmly and hold until the display message disappears.
rolling away before you leave it. Prevent the vehicle from rolling away before you leave it.
You can restart the engine.
Risk of accident 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.
Additionally, the red only)/ (Canada only) (USA only)/ warning lamp lights up in the instrument cluster and a warning (Canada only) warning lamp lights up in the instrument cluster and a warning tone sounds.
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. Consult a qualified specialist workshop.
This will not rectify the malfunction. Do not add brake fluid. This will not rectify the malfunction.

WARNING
Driving with the message Check Brake Fluid Level displayed can result in an accident. Have your brake system checked immediately.
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.

Display messages Possible causes/consequences and Solutions
USA only: one or more of the main functions in the mbrace system USA only: one or more of the main functions in the mbrace system are malfunctioning.
Canada only: one or more of the main functions of the TELEAID system are malfunctioning.
system checked at a qualified USA only: have the mbrace system checked at a qualified specialist workshop.
TELEAID system checked at a qualified Canada only: have the TELEAID system checked at a qualified specialist workshop.
Risk of accident PRE-SAFE® Brake is temporarily inoperative if: Risk of accident

PRE-SAFE® Brake is temporarily inoperative if:
• the DISTRONIC PLUS cover in the radiator grill is dirty.
• the sensors in the bumpers are dirty.
• its function is impaired due to heavy rain or snow.
• the radar sensor system is temporarily inoperative, e.g. due to electromagnetic radiation emitted by nearby TV or radio stations or other sources of electromagnetic radiation.
• you switch off ESP® (AMG vehicles only).
• the system is outside the operating temperature range.
• the on-board voltage is too low.
PRE-SAFE® Brake is operational again and the display message disappears if:
• the dirt (e.g. slush) drops away while the vehicle is in motion.
• the system detects that the sensors are fully available again.
• you switch ESP® on again (AMG vehicles only).
• the system is within the operating temperature range.
If the display message continues to be displayed:
cover in the radiator grill. Clean the DISTRONIC PLUS cover in the radiator grill.
Restart the engine. Clean the bumpers.
Wait until the battery is Restart the engine.
sufficiently charged. Wait until the battery is sufficiently charged.
Risk of accident PRE-SAFE® Brake is defective. BAS PLUS or the distance warning Risk of accident

PRE-SAFE® Brake is defective. BAS PLUS or the distance warning signal may also have failed.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident There is a malfunction in the SRS (Supplemental Restraint Risk of accident

There is a malfunction in the SRS (Supplemental Restraint System). The also lights up in the instrument warning lamp also lights up in the instrument cluster.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident SRS has malfunctioned at the front on the left or right. The Risk of accident

SRS has malfunctioned at the front on the left or right. The warning lamp also lights up in the instrument cluster. warning lamp also lights up in the instrument cluster.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident SRS has malfunctioned at the rear on the left or right. The Risk of accident

SRS has malfunctioned at the rear on the left or right. The warning lamp also lights up in the instrument cluster. warning lamp also lights up in the instrument cluster.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident SRS has malfunctioned at the rear center. The Risk of accident

SRS has malfunctioned at the rear center. The also lights up in the instrument cluster. warning lamp also lights up in the instrument cluster.
specialist workshop. Visit a qualified specialist workshop.
Risk of accident There is a malfunction in the left-hand and/or right-hand window Risk of accident

There is a malfunction in the left-hand and/or right-hand window curtain air bag. The warning lamp also lights up in the warning lamp also lights up in the instrument cluster.
specialist workshop. Visit a qualified specialist workshop.

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.

Display messages Possible causes/consequences and Solutions
The front-passenger air bag is enabled during the journey, even The front-passenger air bag is enabled during the journey, even though:
• a child, a small adult or an object weighing less than the system's weight threshold is located on the front-passenger seat.
• the front-passenger seat is unoccupied.
The system may detect objects or forces applying additional weight on the seat.
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.
Switch off the ignition. Engage the parking brake.
Open the front-passenger Switch off the ignition.
door. Open the front-passenger door.
child restraint system from the frontpassenger Remove the child and the child restraint system from the frontpassenger seat.
child in a child restraint system on a If necessary, secure the child in a child restraint system on a suitable rear seat.
objects on the seat adding to the Make sure that there are no objects on the seat adding to the weight.
The system may otherwise detect the additional weight and interpret the seat occupant's weight as greater than it actually is.
close the front-passenger door and Keep the seat unoccupied, close the front-passenger door and switch on the ignition.
Observe the and the indicator lamp and the multifunction display and check the following:
Seat unoccupied and ignition switched on:
• the light up and remain lit. When indicator lamp must light up and remain lit. When the indicator lamp is on, OCS has deactivated the front-passenger air bag.
• the Front Passenger Airbag Enabled See Operator's Manual or Front Passenger Airbag Disabl'd See Operator's Manual display messages must not appear in the multifunction display. Wait for a period of at least 60 seconds until the necessary system checks have been completed and to make sure that the display messages do not appear in the multifunction display.
If these conditions are fulfilled, the front-passenger seat can be occupied again. Whether the indicator lamp remains lit indicator lamp remains lit or goes out depends on how OCS classifies the occupant.
If the conditions are not fulfilled, the system is not operating correctly.
specialist workshop immediately. Visit a qualified specialist workshop immediately.

WARNING
If the off even after performing the above corrective steps, do indicator lamp remains off even after performing the above corrective steps, do not have any children 12 years old and under and other small individuals use the front-passenger seat until the system has been repaired.

Display messages Possible causes/consequences and Solutions
The front-passenger air bag is deactivated during the journey even The front-passenger air bag is deactivated during the journey even though an adult or a person larger than a certain size is occupying the front-passenger seat. If additional forces are applied to the seat, the system may interpret the occupant's weight as lower than it actually is.
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.
Switch off the ignition. Engage the parking brake.
Have the occupant get out Switch off the ignition.
of the vehicle. Have the occupant get out of the vehicle.
close the front-passenger door and Keep the seat unoccupied, close the front-passenger door and switch on the ignition.
Observe the and the indicator lamp and the multifunction display and check the following:
Seat unoccupied and ignition switched on:
• the light up and remain lit. When indicator lamp must light up and remain lit. When the indicator lamp is on, OCS has deactivated the front-passenger air bag.
• the Front Passenger Airbag Enabled See Operator's Manual or Front Passenger Airbag Disabled See Operator's Manual display messages must not appear in the multifunction display. Wait for a period of at least 60 seconds until the necessary system checks have been completed and to make sure that the display messages do not appear in the multifunction display.
If these conditions are fulfilled, the front-passenger seat can be occupied again. Whether the indicator lamp remains lit indicator lamp remains lit or goes out depends on how OCS classifies the occupant.
If the conditions are not fulfilled, the system is not operating correctly.
specialist workshop immediately. Visit a qualified specialist workshop immediately.

WARNING
If the lit with an adult occupant on the front-passenger seat indicator lamp remains lit with an adult occupant on the front-passenger seat even after performing the above corrective steps, do not have any passenger use the frontpassenger seat until the system has been repaired.

    See also:

    Hill start assist
    Hill start assist helps you when pulling away forwards or in reverse on an uphill gradient. It holds the vehicle for a short time after you have removed your foot from the brake pedal. This gives ...

    Downhill gradients
    On long and steep gradients, you must reduce the load on the brakes by shifting early to a lower gear. This allows you to take advantage of the engine braking effect and helps avoid overhea ...

    Displaying details
    Select Data/Connections in the telephone basic menu by sliding and turning the COMAND controller and press to confirm. Select Bluetooth Telephones and press to confirm. Select the des ...