Troubleshooting guide

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www.bendix.com 1-800-AIR-BRAKE (1-800-247-2725)
Advanced ABS
Yaw Stability
Yaw stability counteracts the tendency of a vehicle to
spin about its vertical axis. During operation, if the
friction at the tires is not sufficient to oppose lateral
(side) forces, one or more of the tires can slide, causing
the truck/tractor to spin. These are referred to as
under-steer or over-steer situations. Generally, shorter
wheelbase vehicles (tractors, for instance) have less
yaw stability, while longer wheelbase vehicles (straight
trucks) have greater natural yaw stability. Factors that
influence yaw stability are: wheelbase, suspension,
steering geometry, weight distribution front to rear,
and vehicle tracking.
Stability Systems
During operation, the ECU of the Bendix Advanced
ABS system constantly compares performance models
to the vehicle’s actual movement, using the wheel speed
sensors of the ABS system, as well as lateral, yaw, and
steering angle sensors. If the vehicle shows a tendency
Advanced ABS
to leave an appropriate travel path, or if critical
threshold values are approached, the system will
intervene to assist the driver.
The Bendix ESP system
The ESP
®
functionality of the Bendix Advanced ABS
system responds to a wide range of low- to high-friction
surface scenarios including rollover, jackknife and loss
of control. It is the recommended system for all power
vehicles and especially critical for tractors pulling
trailers. In the case of vehicle slide (over-steer or under-
steer situations), the system will remove the throttle
and then brake one or more of the “four corners of
vehicle” (in addition to potentially braking the trailer),
thus applying a counter-force to better align the vehicle
with an appropriate path of travel. For example, in an
over-steer situation, the system applies the “outside”
front brake; while in an under-steer condition, the
“inside” rear brake is applied.
Driving Scenario:
Driving speed exceeds the threshold,
creating a situation where the vehicle
is prone to rollover on higher-friction
surfaces.
Action by Bendix Stability Solutions:
System applies all brakes to reduce
speed, thereby reducing the
tendency to roll over.