Automatic Traction Control; Enhanced Stability Control - freightliner BUSINESS CLASS M2 Driver Manual

•
If the lamp illuminates momentarily during ve-
hicle operation, then shuts off, a fault was de-
tected and corrected.
•
If the lamp illuminates and stays on during ve-
hicle operation, there is a fault with the trailer
ABS. Repair the trailer ABS system immedi-
ately to ensure full antilock braking capability.
IMPORTANT: If a compatible trailer is con-
nected, and the lamp is not illuminating momen-
tarily when the ignition key is turned to the ON
position, it is possible that the lamp is burnt out.

Automatic Traction Control

Vehicles with electronic engines and ABS may have
Automatic Traction Control (ATC). On these vehicles,
the ATC system automatically limits wheel spin dur-
ing reduced-traction situations. In normal braking ap-
plications, the standard air brake system is in effect.
An additional solenoid valve is installed. During
reduced-traction situations, the ATC solenoid valve
controls air pressure to the modulator valves and
they in turn increase, hold, or reduce pressure to the
appropriate brake chambers to provide better traction
whenever wheel spin occurs.
When the ATC system is in the NORMAL mode, it
will apply gentle braking to the spinning wheel, to
feed power to the wheel(s) with better traction. If
both wheels are spinning, the system will signal the
engine to reduce power.
ATC includes a deep snow and mud option to in-
crease available traction on extra soft surfaces like
snow, mud, or gravel. A momentary contact rocker
switch labeled ATC will be located on the dash.
Pressing the switch will temporarily allow more wheel
spin. The activation of the deep snow and mud op-
tion is indicated by a flashing WHEEL SPIN lamp.
Pressing the switch again will cycle the system back
to normal operation.
NOTICE
The deep snow and mud option is intended to be
used under specific slippery conditions that re-
quire momentary increased wheel spin. Using
this option for an extended period of time may
damage the vehicle brake system.
After the ignition switch is turned on, the TRACTOR
ABS lamp and the WHEEL SPIN indicator lamp illu-
Steering and Brake Systems
minate for about three seconds. After three seconds,
the warning lights go out if all of the tractor's ABS
components are working.
IMPORTANT: If any of the ABS warning lights
do not work as described above, or illuminate
while driving, repair the ABS immediately to en-
sure full antilock braking capability.

Enhanced Stability Control

WARNING
Enhanced Stability Control (ESC) is intended only
as an aid for a conscientious and alert driver.
Carefully read the information in this manual to
understand this system and its limitations. ESC
is not a substitute for safe driving procedures.
Failure to drive safely, and use the system prop-
erly, could result in personal injury and/or death
and property damage.
ESC automatically reduces engine power, applies the
engine brake, and/or applies the tractor and trailer
brakes when the acceleration sensor detects that the
vehicle is at risk of rolling over. In addition, ESC of-
fers the added capability of complete directional sta-
bility (yaw control) in oversteer and understeer condi-
tions to reduce the likelihood of drift-out or jackknife.
The system determines where the driver is attempt-
ing to steer the vehicle and how much brake demand
is required in order to more precisely control the ve-
hicle in an emergency situation.
ESC works by constantly comparing the driver's in-
tention with the vehicle's actual behavior. The system
does this by monitoring systems such as wheel
speed, steering angle, yaw rate, lateral acceleration,
throttle position, and brake application. A central mi-
crocomputer analyzes the collected data and triggers
a response to keep the vehicle on course when an
unstable condition is detected.
The roll stability control system automatically reduces
engine power, applies the engine brake, and/or ap-
plies the tractor and trailer brakes when the accelera-
tion sensor detects that the vehicle is at risk of rolling
over. The control can intervene even before an advi-
sory message is displayed.
When the system detects that the vehicle is at risk of
oversteering or understeering, it applies individual
tractor wheel end brakes and trailer brakes, activates
9.6