299 Controls in detail
Useful features
Roadside Assistance button*b 
The Roadside Assistance buttonb is 
located in the overhead control panel.
1Roadside Assistance buttonb
Press and hold Roadside Assistance 
button b (for longer than 
2 seconds).
A call to a Mercedes-Benz Roadside As-
sistance dispatcher will be initiated. 
The button will flash while the call is in 
progress. The message:
Connecting call appears in the 
multifunction display 
and the audio system is muted.When the connection is established, the 
message: 
Call connected appears in the multi-
function display 
The Tele Aid system will transmit data gen-
erating the vehicle identification number, 
model, color and location (subject to avail-
ability of cellular and GPS signals).
A voice connection between the Roadside 
Assistance dispatcher and the occupants 
of the vehicle will be established. 
Describe the nature of the need for as-
sistance.
The Mercedes-Benz Roadside Assistance 
dispatcher will either dispatch a qualified 
Mercedes-Benz technician or arrange to 
tow your vehicle to the nearest authorized 
Mercedes-Benz Center. For services such 
as labor and/or towing, charges may ap-
ply. Refer to the Roadside Assistance Man-
ual for more information.
These programs are only available in the 
USA:
Sign and Drive services: Services such 
as jump start, a few gallons of fuel or 
the replacement of a flat tire with the 
vehicle spare tire are obtainable.
iThe indicator lamp in the Roadside Assis-
tance buttonb remains illuminated in red for 
approximately 10 seconds during the system 
self-check after switching on the ignition (togeth-
er with the SOS button and the Information 
button*}).
See system self-check (
page 296) if the indi-
cator lamp does not come on in red or stays on 
longer than approximately 10 seconds.
If the indicator lamp in the Roadside Assistance 
buttonb is flashing continuously and no 
voice connection to the Response Center was 
established, the Tele Aid system could not ini-
tiate a Roadside Assistance call (e.g. the relevant 
telephone network is not available). The mes-
sage:
Call failed appears in the multifunction 
display for approximately 10 seconds
Roadside Assistance calls can be terminated us-
ing the t button on the multifunction steer-
ing wheel or the respective button for ending a 
telephone call on the audio system or the 
COMAND* head unit. 
361 Operation
Winter driving
Snow chains
Snow chains should only be driven on 
snow-covered roads at speeds not to 
exceed 30 mph (50 km/h). Remove chains 
as soon as possible when driving on roads 
without snow.
Please observe the following guidelines 
when using snow chains:
Use of snow chains is not permissible 
with all wheel/tire combinations 
(
page 467).
Use snow chains in pairs and on rear 
wheels only. Follow the manufacturer’s 
mounting instructions.
Only use snow chains that are 
approved by Mercedes-Benz. Any 
authorized Mercedes-Benz Center will 
be glad to advise you on this subject.
Use of snow chains may be prohibited 
depending on location. Always check 
local and state laws before installing 
snow chains.
Do not use snow chains on the spare 
wheel (
page 467).
Warning!G
If you use your spare tire when winter tires 
are fitted on the other wheels, be aware that 
the difference in tire characteristics may 
very well impair turning stability and that 
overall driving stability may be reduced. 
Adapt your driving style accordingly.
Have the spare tire replaced with a winter 
tire at the nearest authorized 
Mercedes-Benz Center.!Some tire sizes do not leave adequate clear-
ance for snow chains. To help avoid serious dam-
age to your vehicle or tires, make sure that the 
use of snow chains is permissible as specified in 
the Technical data section of this Operator’s 
Manual, see “Rims and tires” (
page 467).
!If snow chains are mounted to the front 
wheels, they may scrape against the body or axle 
components. The tires or the vehicle could be 
damaged as a result.
iWhen driving with snow chains, you may 
wish to deactivate the ESP® (page 63) before 
setting the vehicle in motion. This will improve 
the vehicle’s traction.