System self-test

After you have switched on the ignition, the system carries out a self-diagnosis.

WARNING A malfunction in the system has been 
A malfunction in the system has been detected if one of the following conditions occurs:
• the indicator lamp in the SOS button does not light up during the system selfdiagnosis.
• the indicator lamp in the Assistance button does not light up during Roadside
Assistance button does not light up during the system self-diagnosis.
• The indicator lamp in the button does not light up during selfdiagnosis information button does not light up during selfdiagnosis of the system.
• the indicator lamp in the SOS button, or information button continues to Roadside Assistance button or be lit red information button continues to be lit red after the system self-diagnosis.
• The Tele Aid Inoperative or Tele Aid
Not Activated message appears in the multifunction display after the system selftest.
If a malfunction is indicated as outlined above, the system may not operate as expected. In the event of an emergency, assistance must be summoned by other means.
Have the system checked at the nearest authorized Mercedes-Benz Center or contact the following service hotlines:
• USA: Response Center under
888-990-9007
• Canada: Customer Service at
1-888-923-8367

    See also:

    Emergency Tensioning Devices, belt force limiters
    The front seat belts and the outer seat belts in the rear are equipped with ETDs and seat belt force limiters. The ETDs tighten the seat belts in an accident, pulling them close against the bod ...

    Brake fluid level
    If you notice that the brake fluid level in the brake fluid reservoir has fallen to the MIN mark or less, check the brake system immediately for leaks. Also check the thickness of the brake lini ...

    Mounting a new wheel
    WARNING   Always replace wheel bolts that are damaged or rusted. Never apply oil or grease to wheel bolts. Damaged wheel hub threads should be repaired immediately. Do not continue to ...