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Acceleration Slip Regulation (ASR)
The acceleration slip regulation will
engage at all vehicle speeds, if one or
both drive wheels begin to lose traction
and spin due to excessive acceleration.
While engaged, the yellow warning
lamp in the speedometer flashes.
With the acceleration slip regulation
engaged, the brake is applied to the
spinning drive wheel until it regains
sufficient traction. If both drive wheels
lose traction and spin, the brake is
applied to both drive wheels and
simultaneously, engine torque is
limited, to improve the vehicle's
driving stability.
As traction on the road surface
increases, the allowable engine torque
also increases again and the brake is no
longer applied to drive wheels.
Important!
If the ASR warning lamp flashes, adapt
your speed and driving to the
prevailing road conditions.
Caution!
If the vehicle is towed with the front
axle raised (see Towing the vehicle in
Index), the engine must be shut off.
Otherwise, the acceleration slip
regulation will immediately be engaged
and will apply the rear wheel brakes.
Notes:
If the ASR malfunction indicator lamp
comes on with the engine running, a
malfunction has been detected.
Pressing the accelerator pedal will
require greater effort. Only partial
engine output is available.
Have the ASR checked at your
authorized Mercedes-Benz dealer as
soon as possible.
With the ABS malfunctioning, the
ASR is also switched off.
Driving the vehicle with varied size
tires will cause the wheels to rotate at
different speeds, therefore the
acceleration slip regulation may
activate (yellow ASR warning lamp in
instrument cluster comes on). For this
reason, all wheels, including the spare
wheel, must have the same tire size.
When testing the parking brake on a
brake test dynamometer, the engine
must be shut off. Otherwise, the
acceleration slip regulation will
immediately be engaged and will apply
the rear wheel brakes.
In winter operation, the maximum
effectiveness of the acceleration slip
regulation is only achieved with
Mercedes-Benz recommended M+S
radial-ply tires and/or snow chains.
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