BENDIX® GSBC® (GLOBAL SCALABLE
BRAKE CONTROL) SYSTEM
OPERATOR’S MANUAL

This booklet contains important operational and safety information.

This page intentionally left blank.

TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Important Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

System Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Vehicle Inspection & Pre-Trip Inspection . . . . . . . . . . . . . . . . . . . . . . 7-8
Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
System Display & Behavior at Startup . . . . . . . . . . . . . . . . . . . . . . 10-13
Dash Display Indicators and Operation . . . . . . . . . . . . . . . . . . . . . 14-15
GSBC System Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-22
GSBC System - What to Expect . . . . . . . . . . . . . . . . . . . . . . . . . .

23-25

System Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-38
Acronyms and Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

INTRODUCTION
This Operator’s Manual provides an overview of the Bendix® Global Scalable Brake
Control (hereafter known as GSBC®) system. This manual explains the components,
features, functions, and known system limitations. There are also example
descriptions and explanations of the driver alerts and system interventions that can
be expected during operation.
Read this manual thoroughly before operating the system. Be familiar with the
possible system actions, alerts, and its limitations.
Keep this manual in the vehicle as a reference at all times.
NOTE: All of these alerts and actions are part of the GSBC system’s feature set released
by Bendix. It is possible for this Operator’s Manual to be moved from vehicle to vehicle.
Always verify the features that are included on your vehicles with your dealer or OEM.
For additional information about Bendix® systems, visit bendix.com, contact
your local Bendix sales representative, or call 1-800-AIR-BRAKE (1-800-247-2725).
Representatives are available to assist you Monday through Thursday, 8:00 a.m. to
6:00 p.m. and Friday, 8:00 a.m. to 5:00 p.m. ET.
Information about features, operation, and other aspects discussed in this manual
are subject to change and updating and are posted on the document library located
at B2Bendix.com.

3

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

OVERVIEW
The Bendix® GSBC® is an Electronic Braking System (EBS) that controls the service
brakes of the vehicle. The system is comprised of both hardware and software
components that work together to control the service braking system of the vehicle.
EBS utilizes electronic control systems but continues to use air to apply and release
the parking and service brakes of the vehicle.
GSBC can provide additional functionality including Bendix® Electronic Stability
Program (ESP).
For more descriptions of these features, refer to the System Features section on page 16.

Bendix safety technologies complement safe driving practices. No commercial
vehicle safety technology replaces a skilled, alert driver exercising safe driving
techniques and proactive, comprehensive driver training.

Improper use of the GSBC system can result in a potential collision causing
property damage, serious injuries, or death. Be sure to read, understand,
and follow all these instructions carefully.

IMPORTANT
Bendix®-brand Electronic Control Units (ECUs) are not designed to store data for
purposes of accident reconstruction, and Bendix® ACom® Diagnostic Software
is not intended to retrieve data for purposes of accident reconstruction. Bendix
makes no representations as to the accuracy of data retrieved and interpreted
from ECUs for purposes of accident reconstruction. Bendix does not offer
accident reconstruction services or interpretation of stored data. Bendix ECUs
are not protected from fire, loss of power, impact damage, or other conditions
that may be sustained in a crash situation and may cause data to be unavailable
or irretrievable.

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

4

IMPORTANT SAFETY INFORMATION
When necessary, Bendix® GSBC® automatically intervenes to reduce the accelerator
pedal input and/or apply the service brakes to help you maintain stability during
potential loss-of-control or rollover events. The GSBC stability system does not replace
the need for the driver to remain alert, react appropriately and in a timely manner,
and use safe driving practices. Bendix safety technologies complement safe driving
practices. Responsibility for the safe operation of the vehicle remains with you, the
driver, at all times.
If you determine that a hazard or unsafe condition exists, you should take all necessary
actions immediately. Never wait for the system to intervene.
To minimize unexpected deceleration and reduce the risk of a potential collision, the
driver must:
•

Avoid aggressive driving maneuvers, such as sharp turns or abrupt lane
changes at high speeds, which might trigger the stability system; and

•

Always operate the vehicle safely, drive defensively, anticipate obstacles and
pay attention to road, weather and traffic conditions. Bendix brake control
systems are no substitute for prudent, careful driving.

Bendix ESP is designed and optimized for trucks and for tractors that tow single trailers.
If a tractor equipped with Bendix ESP is used to power multiple trailer combinations
(known as “doubles” or “triples”), the effectiveness of Bendix ESP may be greatly reduced.
Extremely careful driving is always required when towing doubles or triples. Excessive
speed and aggressive maneuvers – such as sharp turns, sudden steering inputs, or
abrupt lane changes – should be avoided. For more information about Bendix ESP, refer
to the System Features section on page 16.

5

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

SYSTEM LIMITATIONS
All systems have limitations, including the Bendix® GSBC® system. It is always the
responsibility of the driver to operate the vehicle safely. There may be situations
where the GSBC system unexpectedly issues warnings, applies brakes, or does not
respond in a manner consistent with your expectations.
Cautious driving practices such as maintaining an adequate following distance with
the forward vehicle, not speeding, anticipating obstacles and adjusting your vehicle’s
speed for traffic, weather and road conditions are essential for safe operation which
is the responsibility of you, the driver, at all times.

LIMITATIONS OF STABILITY SYSTEMS
The effectiveness of the Electronic Stability Program (ESP) functionality within the
GSBC system may be greatly reduced if:
•

The load shifts due to improper retention, accident damage, or the
inherently mobile nature of some loads (for example, hanging meat, live
animals or partially laden tankers);

•

The vehicle has an unusually high – or off-set – center of gravity (CG);

•

One side of the vehicle drops off the pavement at an angle that is too
large to be counteracted by a reduction in speed;

•

The vehicle is used to haul double or triple trailer combinations;

•

If very rapid steering changes are attempted at high speeds;

•

There are technical problems with suspension leveling of the tractor or
trailer resulting in uneven loads;

•

The vehicle is maneuvering on a high banked road creating either additional
side forces due to the weight (mass) of the vehicle, or a deviation between
expected & actual yaw rates;

•

The vehicle experiences a significant mechanical problem or failure. ESP will
not prevent serious problems (for example, tire failures) from impacting the
driver’s ability to control the vehicle;

•

Gusty winds are strong enough to cause significant side forces on the vehicle
and any towed vehicles.

To maximize the effectiveness of ESP functionality within the GSBC system, drivers
need to exercise extreme caution at all times and should avoid sharp turns, sudden
steering adjustments, or abrupt lane changes at high speeds, and any loads should
be properly secured at all times.

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

6

TRUCK CHASSIS MODIFICATIONS
If the vehicle’s chassis components are altered, (for example, a wheel base extension
or reduction; tag axle addition or removal; a major body change such as conversion
of a tractor into a truck; or an axle, suspension, or steering system component
modification) the GSBC® ECU must be updated to reflect these changes. Contact
your OE vehicle manufacturer prior to making any modifications to your vehicle.

If you modify your vehicle and do not update the GSBC ECU, the GSBC system
may fail to function as intended. Serious vehicle braking and performance
issues could result, including unnecessary ESP system interventions, exceeding
regulated stopping distance, and/or system faults leading to loss of electronic
functions. These types of failures can lead to a loss-of-control of the vehicle,
potential collisions, property damage, serious injuries, or death.

If replacement tires are used that are a different diameter from the OEMspecified tire size, the brake control system must be updated with the new
tire size using the appropriate diagnostic tool. Contact your OE for more
information.

VEHICLE INSPECTION
For experienced drivers familiar with Bendix brake control systems, a pre- or post-trip
inspection on a vehicle with GSBC is similar to the inspection procedure for previous
Bendix systems. For a thorough inspection procedure for a Bendix air brake system,
refer to the following documents. For new information specific to the Bendix GSBC
system, refer to the information on page 8.
•

BW2676 (for components located outside the cab)

•

BW2677 (for components located inside the cab)

7

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

PRE-TRIP INSPECTION INFORMATION
The Bendix® GSBC® system is an Electronic Braking System (EBS) which differs from
previous generation Bendix brake systems. This results in some changes to your
pre-trip inspection process:
Indicator Lamps: There is an additional lamp on the dashboard as compared to
previous systems. This red “BRAKE” lamp should briefly illuminate (for approximately
3 seconds) when the vehicle is first powered on, but the lamp should not stay
illuminated. If this lamp stays illuminated, it indicates a fault with the system or
function described by the lamp. For more information about this, or, for more
instructions on what to do if the lamp stays illuminated on the dashboard, refer to
the Display Indicators section on page 14.
Change in Components: GSBC is comprised of fewer components than previous
systems. As a result, valves that an experienced driver may be accustomed to seeing
during pre-trip inspections will not be present on the vehicle.
When conducting a pre-trip inspection, use the following table to help locate the
main components of a GSBC Service Braking System.
Main Components Generic Locations
Name

Location

Function

FBM (Foot Brake
Module)

Firewall, connected to the
brake pedal

Turns foot motion into electronic
request for service braking

1-Channel EPM
(Electro-Pneumatic
Module)

Above left frame rail in front
of the cab, under hood;
occasionally on accessory
axles, like lift axles

Smart relay valve to control service
pressure on the steer axle or lift axle

Modulators

Frame rail inside left and right
steer wheels

Provide steer wheel specific
modulation of air pressure to prevent
wheel lockup and provide vehicle
stability

2-Channel EPM
(Electro-Pneumatic
Module)

Frame rail or crossmember
close to the controlled axle(s)

Smart relay valve to control service
pressure on the steer axle(s)
Note: Vehicles may have between one
and three 2-Channel EPMs, depending
on the axle configuration and layout

eTPCM (Electronic
Trailer Pressure Control
Module)

Back of cab, close to the
trailer air lines

Smart relay valve to electronically
control pressure to the trailer

Electronic Control Unit
(ECU)

Rigidly mounted to the
exterior of the vehicle;
typically under the cab on the
framerail

Controls the entire GSBC system and
provides an interface between the
vehicle and the braking system

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

8

BENDIX GSBC SYSTEM OPERATION
Bendix® GSBC® will be controlled and operated in a similar manner to previous Bendix
brake control systems. The driver will always be in control of the service brakes, which
will be operated by the brake pedal under the driver’s foot.
Experienced drivers may notice more solenoid noises during service brake operation.
This is normal and is an audible confirmation that the system is operating as expected.
GSBC can operate in two modes: Electronic Primary Mode and Pneumatic Backup
Mode. In Electronic Primary Mode, the driver’s movement of the brake pedal is
translated into an electronic request for air that is interpreted by the central Brake
Control ECU (Electronic Control Unit) and sent to the Electro-Pneumatic Modules
(EPMs) that have taken the place of the traditional relay valve. This electronic
control allows the system to deliver the precise pressure required to each controlled
foundation brake to ensure the desired brake response and provide improved brake
balance and feel across different load conditions.
NOTE: In the event of a serious system malfunction, the GSBC ECU may be unable
to maintain electronic control of the system. In the event of this unlikely occurrence,
the system will revert to Pneumatic Backup Mode.
In Pneumatic Backup Mode, the system will rely on the pneumatic pressure sent
by the foot brake module to the EPMs. This will ensure that the vehicle has all of the
designed braking power available to bring the vehicle to a safe stop.
When the system is operating in this mode:
•

A red warning lamp will appear on the dashboard accompanied by “a Truck
brake failure” message.

•

All of the electronic driver safety features (ABS, Stability Control, Traction
Control, and so on) may be unavailable.

•

The system will be unable to prevent wheel end lockup, or provide stability
assistance.

•

Brake pedal feel and response will likely be different as compared to
operation in Electronic Primary Mode.

As a result of these changes and limitations, drivers must immediately bring
the vehicle to a safe stop if the red warning lamp appears on the dashboard
and stays illuminated. The vehicle must be serviced as soon as possible by
a qualified service facility, and the issue(s) that caused the system to enter
Pneumatic Backup Mode should be identified, addressed, and corrected.
Only after a repair has been completed, and the fault is verified to be cleared, can
the vehicle be returned to service.

9

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

BENDIX GSBC DISPLAY & BEHAVIOR AT STARTUP
When the Bendix® GSBC® system is first powered on at vehicle ignition, the brake
control system does not require input or actions from the driver. For experienced
drivers, there are a few things that are different relative to previous Bendix® brake
control products:

POWER ON SELF TEST (POST) SEQUENCE/CHUFF TEST
When GSBC is first powered on with the ignition key, the system will conduct a Power
On Self Test (POST). This is a brief self-check that the system performs to check for
basic operation of the system, components, internal software and communications
functions.
NOTE: For experienced drivers familiar with the Bendix “Chuff” test, this POST test
performs a similar function, but it will not make an audible noise. This means that
the Chuff test sound of solenoids clicking during key on will not be present. The
lack of clicking sound(s) during key on does not indicate a problem with the brake
control system or its operation.

FOOT BRAKE MODULE (FBM) WAKEUP
While powered, the GSBC system is always ready for the driver to press the foot brake
to request the service brakes. This FBM function allows the driver to step on the
service brake pedal while the vehicle is otherwise off, and still deliver the requested
service brake pressure to the foundation brakes. This activity does not require the
key to be in the ignition or the vehicle to be running – only that power has not been
cut using a battery disconnect switch or similar device.
NOTE: If there is no air in the service reservoirs, the brake pedal activation will result
in solenoids clicking, but no air being delivered to the foundation brakes.

SOLENOID CONTROL
When in Electronic Primary Mode, the GSBC system will use solenoids to apply
and release service brake pressure at the vehicle’s foundation brakes. If the system
encounters a fault significant enough to prevent the electronic system from
operating, (see the Pneumatic Backup Mode reference on page 9) these solenoids will
not activate and there will not be an audible clicking sound. Depending on how loud
the environment surrounding the vehicle is when this occurs (engine noise, other
vehicles, ambient noises, radio, etc.), the clicking may or may not be apparent to the
driver in the cab. This solenoid noise is normal and indicative of the brake control
system operating as intended. Once air pressure is restored to the reservoirs, the
brake control system will once again deliver air to the foundation brakes as normal.

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

10

BENDIX GSBC DISPLAY & BEHAVIOR AT STARTUP (CONT.)
IMPORTANT
The driver should verify the proper operation of all installed indicator lamps
when applying ignition power and during vehicle operation. Lamps that do
not illuminate as expected when ignition power is applied, or red/yellow lamps
that remain illuminated after startup, indicate the need for service and/or
maintenance.
NOTE: Refer to the GSBC Dash Display Indicator Lamps and Operation section starting
on page 14 for more information about each lamp.

ELECTRONIC BRAKING SYSTEM (EBS) BRAKE INDICATOR LAMP (NEW)
A red EBS brake critical malfunction indicator lamp is located in the vehicle display.
This indicator lamp will illuminate for approximately three (3) seconds during the bulb
check portion of the startup sequence when the vehicle key is turned from “off” to
“ignition.” If this warning lamp appears during normal operation, it is indicative of a
critical failure within the brake control system, and the vehicle should be brought to a
safe stop as quickly as possible. Once safely stopped, the driver must have the vehicle
serviced immediately by a qualified technician to restore full system functionality.

ELECTRONIC BRAKING SYSTEM (EBS) DASH DISPLAY WARNING (NEW)
A yellow EBS dash display warning will display with the text “Contact Workshop
Truck Brake Malfunction” when a fault occurs. This dashboard warning may be
accompanied by other warning lamps indicating specific features or functions that
may be inoperative. The vehicle should be serviced as soon as possible by a qualified
technician to restore full system functionality.

ANTILOCK BRAKING SYSTEM (ABS) INDICATOR LAMP
An yellow ABS indicator lamp is typically located in the vehicle display. At each
ignition, the ABS Indicator Lamp should illuminate for approximately three (3)
seconds and then turn off. If the ABS indicator lamp does not illuminate at ignition
or if it remains on for more than three (3) seconds after ignition, or if it illuminates
continuously while you are driving, the ABS system may not be fully functional or
may be completely disabled. Have the vehicle serviced immediately by a qualified
technician to restore full ABS functionality.

11

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

BENDIX GSBC DISPLAY & BEHAVIOR AT STARTUP (CONT.)
NOTE: Refer to the GSBC Dash Display Indicator Lamps and Operation section starting
on page 14 for more information about each lamp.

TRAILER ABS INDICATOR LAMP
The yellow trailer ABS indicator lamp is typically located in the vehicle display of
tractors or other towing vehicles. The trailer ABS indicator lamp functions similarly
to the tractor ABS indicator lamp, as long as a trailer with a trailer ABS system is
connected electrically to the towing vehicle. At each ignition, the trailer indicator
lamp should illuminate for approximately three (3) seconds and then turn off. If the
lamp does not turn off, one of the vehicle(s) connected to the power unit may have
a faulty trailer ABS unit. If there is no trailer, the trailer does not have a trailer ABS
unit, or if the trailer ABS unit is powered only by brake lamp power, the lamp will
not remain illuminated.
All new trailers built after March 1, 2001 must support the dashboard mounted
trailer ABS indicator lamp. Trailers built after March 1, 1998 (in the United States)
or April 1, 2000 (in Canada) must be equipped with a trailer ABS unit, but are
not required to support a dashboard mounted trailer ABS indicator lamp.
The mode of operation of the trailer ABS indicator lamp (as equipped) will vary
depending on how the ABS system is powered.
•

For full-time-powered ABS (usually obtaining power over the blue wire of
the J560 connector): The trailer ABS warning lamp will function just like the
tractor ABS indicator lamp.

•

For brake-light-only powered ABS: Each time the brakes are applied when
the vehicle is stationary, the indicator lamp will come on for approximately
three (3) seconds and then turn off. If the lamp remains on during braking, the
trailer’s ABS may not be operating. The trailer will retain normal service braking,
although without the benefits of ABS. Have the trailer serviced as soon as possible
to restore ABS operation.

In both cases where the warning lamp stays illuminated for longer than three (3)
seconds, the trailer will retain normal service braking, although without the benefits
of ABS. Have the trailer serviced as soon as possible to restore ABS operation.

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

12

BENDIX GSBC DISPLAY & BEHAVIOR AT STARTUP (CONT.)
NOTE: Refer to the GSBC Dash Display Indicator Lamps and Operation section starting
on page 14 for more information about each lamp.

AUTOMATIC TRACTION CONTROL (ATC) STATUS/INDICATOR LAMP
If the vehicle is equipped with the Automatic Traction Control (ATC) feature, an
indicator lamp may be located in the vehicle display. At each ignition, the ATC
Indicator Lamp will illuminate for approximately three (3) seconds and then turn
off. If the ATC indicator lamp does not illuminate at ignition – or if it remains on
(not flashing) after ignition, or if it illuminates steadily (not flashing) while you are
driving – the ATC system may not be fully functional or may be completely disabled.
Have the vehicle serviced immediately by a qualified technician to restore full ATC
system functionality.

BENDIX® ELECTRONIC STABILITY PROGRAM® (ESP) INDICATOR LAMP
A yellow Electronic Stability Program (ESP) indicator lamp is located in the dashboard.
At each vehicle ignition, the ESP indicator lamp should illuminate for approximately
three (3) seconds and then turn off. If the lamp does not illuminate at ignition, or if
the indicator lamp remains on for more than three (3) seconds after ignition, or if it
illuminates while you are driving, the ESP system may not be fully functional or may
be completely disabled. If the ESP is completely disabled or not functioning properly,
have the vehicle serviced immediately by a qualified technician to restore full ESP
functionality. During an ESP intervention, the lamp will flash rapidly.

13

BW8207 Bendix Global Scalable Brake Control (GSBC) System Operator’s Manual

GSBC DISPLAY INDICATOR LAMPS AND OPERATION - NORMAL
BRAKE

Vehicle in Special Operation

Vehicle in Normal Operation with Vehicle Moving

Ignition on - startup

EBS
Lamp
On for
approx.
three (3)
seconds*

ABS
Lamp

ESP
Lamp

On for
On for
approx.
approx.
three (3) three (3)
seconds* seconds*

ATC
Lamp

TABS
Lamp

On for
approx.
three (3)
seconds*

On for
approx.
three (3)
seconds*

Description

*If any of the described
lamp behaviors do not
occur, or, if the lamp remains
on continuously during
operation, have the vehicle
No
serviced by a qualified
On for
On for
On for
On for