BENDIX BW2596 Fascicule

The Bendix

®

 ESP

®

 stability system, available on many tractor 

& truck 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 service 

department.  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 (in addition to potentially applying trailer brakes), 

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 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.