BENDIX BW2842 Fascicule

The Bendix

®

 ESP

®

 stability system, available on select coach 

models, helps drivers maintain control of their vehicles during loss 

of control, jackknife and rollover events by applying select brakes 

and reducing throttle, slowing the vehicle down, and helping to 

keep the driver in control.  While much of the system utilizes 

standard ABS brake components, such as wheel speed sensors, 

modulators and an electronic control unit (ECU), there are a few 

additional considerations technicians should keep in mind when 

performing service on Bendix

®

 ESP

®

-equipped vehicles.

Before a vehicle is delivered to a customer, a parameter set 

tuned for the specific vehicle configuration is loaded into the ECU 

along with the VIN at the OE factory.  This “performance-tuning” 

ensures optimal performance of the Bendix

 ESP

 system for 

the specific vehicle configuration.  It also means that the ECU 

for that specific vehicle cannot be used in any other vehicle, 

even if the configuration is the same.  (Note: If the Bendix

 ESP

 

ECU needs replacement, an ECU with the parameter set for that 

specific vehicle identified by VIN needs to be ordered from the OE 

factory.  It is not possible to replace an EC-60

™

 Advanced ECU 

with one from another vehicle.  The VIN on the ECU must match 

the specific vehicle.)

Out on the road, the Bendix

 ESP

 ECU constantly compares 

these known parameters to the vehicle’s actual movement, using 

the wheel speed sensors of the ABS system, as well as lateral 

acceleration, yaw rate, and steering angle sensors.  If the vehicle 

shows a tendency to leave an appropriate travel path, or if critical 

threshold values are approached, the system will intervene 

automatically to assist the driver. 

System intervention can vary, depending on the type of event.  

In the case of a potential roll event, the system will override the 

throttle and quickly apply brake pressure to slow the vehicle below 

a critical threshold.

The Bendix

 ESP

 system goes further than roll stability-only 

systems to help maintain vehicle control.  The addition of the yaw 

and steering angle sensors provide enhanced performance of the 

system on slippery surfaces, such as rain-slicked, snow-covered 

or icy pavement.  In the case of vehicle slide, skid or spin (“over-

steer” or “under-steer” situations), the system will reduce the 

throttle and then brake one or more of the “four corners” of the 

vehicle, thus applying a counter-force to better align the vehicle 

with an appropriate path of travel.  The system typically reacts 

sooner than the driver could, but the driver always remains in 

control and is able to apply additional braking pressure as needed.

By utilizing the ABS brake system as a base, the core components 

of the Bendix

 ESP

 system (wheel speed sensors, modulators, 

traction, relays and ECUs) remain essentially the same.  Your 

current service procedures will be similar.  The additional 

components (yaw rate / lateral accelerometer, steering angle and 

pressure sensors) are based on proven technology with millions 

of miles in use.  Repair to these sensors is limited to direct part 

replacement and reconfiguration via Bendix

®

 ACom

®

 diagnostic 

software.

If there is an issue with the stability system, the automatic traction 

control (ATC) lamp or stability system lamp (ESP or ESC) will 

remain lit. If the vehicle ABS system is also affected, both the 

ABS warning lamp and the ATC or stability lamp will illuminate.  

In these situations, the vehicle will have partial or no stability 

function, but is still drivable and should be scheduled for service 

as soon as possible.