Not used

8

SENS_CAN_H

17

Not used

9

SENS_CAN_L

18

Not used

Table 12 – X5 Connector Pin Descriptions

Figure 17 – Central ECU X5 Connector Pinout
SD-27-5023V Rev 002 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

21

GSBC Central ECU
REPLACEMENT
DESCRIPTION

BENDIX P/N

Central ECU Mud Cover

K151610

Before removal, replacement, or installation of the Central
ECU, ensure that the vehicle is safe for maintenance.
Refer to the General Safety Guidelines on page 2 before
performing any work on the vehicle.

Table 13 – Central ECU Replacement Parts
If the Central ECU requires replacement, follow these
steps:
1. Record the vehicle model, VIN, year, and date of
manufacture.
2. Record the part number of the Central ECU
(EBS-90).
3. Contact your local dealership or OEM representative
for more information on ordering and replacing a
Central ECU. You will need to provide the above
information so that they can order a new Central
ECU.
4. Once the new part arrives, the authorized OEM
service department or the OEM representative
will program the new Central ECU with same
parameter set that was loaded into the original
Central ECU component at the vehicle OEM
assembly facility.
5. Follow the GSBC Central ECU Removal and
Installation sections of this document.

Each Central ECU (EBS-90) has VIN-specific
programming. DO NOT move a Central ECU from vehicle
to vehicle, regardless of how similar the vehicles are to
each other. If you modify a vehicle and do not update
the Central 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, and/or death.
MOUNTING INFORMATION
The Central ECU is rigidly mounted to the vehicle, typically
on the frame underneath or immediately behind the cab
of the vehicle. It is critical that this component is mounted
securely to a rigid part of the vehicle due to the ESP yaw
rate sensor being located within the Central ECU. This
sensor helps inform the operation of ESP, and loose
mounting bolts, or a mounting location that is not rigid, can
negatively impact system performance.

22

MOUNTING BOLTS
Thread Standard & Value

M8 x 1.5 Thread (3x)

Torque Specs

24 N•m ± 4.8 N•m
(17.7 ft-lbs ± 1.35 ft-lbs)

Table 14 – Central ECU Mounting and Torque
Information
REMOVAL
To remove a Central ECU from a vehicle, complete the
following steps:
1. Before removal, replacement, or installation of
the Central ECU, ensure that the vehicle is safe
for maintenance. Refer to the General Safety
Guidelines on page 2 before performing any work
on the vehicle.
2. Turn the vehicle ignition off.
3. Remove battery power from the vehicle per OEM
instructions.
4. Remove as much contamination as possible
from the Central ECU and Mud Cover prior to
disconnecting electrical connections.
5. If the Central ECU and Mud Cover removal requires
cutting any wire-ties, make note of location for
reassembly.
6. Remove the Mud Cover from the body of the
Central ECU.
7. Inspect the wiring harness and wire loom for
pinching or chaffed wires.
8. Label each electrical connector prior to removing
it from the Central ECU.
9. Disconnect the electrical connectors from the
Central ECU.
10. Inspect the electrical connectors on both the
Central ECU and mating harness for debris,
damage, or corrosion.
11. Note the Central ECU’s assembly mounting
position and orientation on the vehicle.
12. Remove and retain the mounting bolts that secure
the Central ECU.
13. Remove the Central ECU from the vehicle.

SD-27-5023V Rev 002 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

GSBC Central ECU
INSTALLATION

When replacing the Central ECU (EBS-90), verify with
the OEM service department that the unit you are
installing has the the correct VIN-specific programming
applied. If you modify a vehicle and do not update the
Central 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, and/or death.
To install a Central ECU to a vehicle, complete the following
steps:
1. Before removal, replacement, or installation of
the Central ECU, ensure that the vehicle is safe
for maintenance. Refer to the General Safety
Guidelines on page 2 before performing any work
on the vehicle.

3. Torque each of the bolts using the torque
specifications in Table 14 in the Mounting
Information section on page 22.

Do not over tighten! Over-tightening the mounting
hardware can cause damage to the Central ECU
(EBS-90). Damage to the housing from over-torqued
fasteners may not be obvious, and malfunction may
occur some time in the future.
4. Reconnect the electrical connectors to the Central
ECU.
NOTE: The use of dielectric grease is not
recommended by the connector manufacturer.
5. Ensure that wire harness bundles are routed
between the lugs of the ECU housing and Mud
Cover so that the wires are not loose or pinched.
See Figure 19.
Lugs for Wire Harness Bundles

2. Position and secure the Central ECU in the
original mounting orientation as noted in Step 11
of the Removal process using the mounting bolts
retained during removal or new OEM-specified
hardware. See Figure 18.

The Central ECU (EBS-90) should only be mounted in the
factory location and orientation and cannot be moved
from that orientation. Failure to do so could result
in serious vehicle braking and performance issues,
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, and/or death.

Figure 19 – Central ECU Lug Location
6. Replace the Mud Cover being sure that it clicks
into place securely.
7. If applicable, re-secure the wiring harness using
the same location and method that was noted in
Step 5 of the Removal process.
8. Apply power and monitor the vehicle power-up
sequence to verify the proper system operation.
9. Use the appropriate diagnostic software tool to
ensure that there are no DTCs after power-up.

Figure 18 – Central ECU Mounting Bolt Orientation
SD-27-5023V Rev 002 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

23

GSBC Central ECU
CENTRAL ECU TROUBLESHOOTING
NOTE: Prior to performing component troubleshooting
tests, confirm the vehicle harness is intact and functioning
properly. For more information regarding troubleshooting
of the vehicle harness, contact the vehicle OEM.
Power Supply Tests
If the DTC indicates a problem with the power supply to the
Central ECU, first check the connectors and harness per
the following procedure before replacing the ECU.
NOTE: Electrical system troubleshooting tests should only
be performed when the vehicle is not running. If the vehicle
is running, system voltage will vary and could be as high
as 28V. If the vehicle is not running, the battery voltage
should be ~24V.
Required tools:

If the harness shows that power is being delivered to the
Central ECU properly, there are no signs of damage or
corrosion to the harness or connectors, and the fault is
still present, contact the vehicle OEM for assistance in
obtaining a replacement ECU.
CAN Troubleshooting Tests
If a DTC indicates a problem with CAN communications
link, first check the connectors and harness according to
the following procedure before replacing the ECU.
Required tools:

•

Multimeter

•

24V Test load (for example, a 1662 or 7511 bulb
rated for 18V-32V supply voltage)

•

NOTE: 1157 bulbs, commonly used as a test load, are only
rated to 12V and should not be used with a 24V system.
Use only test loads rated for 18V-32V supply voltage
ranges.
Procedure:
1. Measure voltage between the pins (refer to Table
15).

Multimeter

Procedure:
1. Measure resistance and/or continuity between the
pins (refer to Table 16).
2. Take all measurements at the Central ECU harness
connector pins in order to check wire harness and
CAN lines. Probe the connector carefully so that
the terminals are not damaged.
3. The pin-to-pin resistances should read as follows:

2. Take all measurements at the Central ECU harness
connector.

TEST PINS

TEST PINS

MEASUREMENT

X3-5

X3-6

60 + 5 Ohms

3. Place the test load across the battery and ground
connection and measure the battery voltage
with the load attached. Battery to Ground should
measure between 18.5V and 32V.

X3-14

X3-15

60 + 5 Ohms

X3-5

X1-7

X3-5

X1-15

X3-6

X1-7

X3-6

X1-15

X3-14

X1-7

X3-14

X1-15

X3-15

X1-7

X3-15

X1-15

BATTERY

GROUND

X1-15

X1-7

X1-15

X1-8

X1-16

X1-7

X1-16

X1-8

MEASUREMENT

18.5V to 32V

Table 15 – Power Supply Pin Voltages
4. Check for damaged wiring and damaged or
corroded connectors and connections.
5. Check the condition of the vehicle battery and
associated components, verifying that the power
and ground connection are intact, undamaged,
and free of corrosion.
6. Check the vehicle’s electrical charging system
output for proper functionality per the manufacturer’s
instructions.

24

7. Plug the ECU back in after performing the above
checks on the power system, clear all DTCs, and
see if the fault returns.

Open Circuit

Table 16 – CAN Troubleshooting Pin Resistances
If the DTC indicates a problem with a component (other
than the GSBC Central ECU), see the appropriate Service
Data sheet for the component-specific troubleshooting.
Refer to the GSBC Technical Documentation Reference
section of this document.
If the harness shows that the proper resistance is present,
there are no signs of damage or corrosion to the harness or
connectors, and the fault is still present, contact the vehicle
OEM for assistance in obtaining a replacement ECU.

SD-27-5023V Rev 002 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

GSBC System Troubleshooting

GSBC SYSTEM TROUBLESHOOTING

TOOLS REQUIRED

GENERAL

The troubleshooting tools that are commonly required to
diagnose and troubleshoot issues with GSBC:

Troubleshooting a GSBC system is similar to troubleshooting
previous generations of brake control systems.
If a warning message or warning indicator lamp related to
the brake control system is displayed on the dashboard,
refer to BW8207, Bendix GSBC Operator’s Manual, on
B2Bendix.com, or the vehicle owner’s manual from the
manufacturer for more information about the proper
response.

Depending on the severity of the detected fault, it may
be safe to continue the trip and schedule maintenance,
or it may be necessary to pull over safely and tow the
vehicle to a service facility. It is always the operator’s
responsibility to ensure that the vehicle is safe and
legal to drive, and operators must be aware of the laws
and regulations within the regions they are operating.

•

A compatible vehicle communication interface
adaptor that works with the vehicle and the
appropriate diagnostic software

•

The latest version of Bendix® ACom® Diagnostic
Software available on B2Bendix.com or the
appropriate diagnostic software from the vehicle
manufacturer

•

A multimeter

•

24V Test load (for example, a 1662 or 7511 bulb
rated for 18V-32V supply voltage)

NOTE: 1157 bulbs, commonly used as a test load, are only
rated to 12V and should not be used with a 24V system.
Use only test loads rated for 18V-32V supply voltage
ranges.

IMPORTANT
When a vehicle equipped with GSBC arrives for service
– with or without a warning indicator lamp active – follow
this procedure to diagnose any active faults with the GSBC
system:
1. Connect the vehicle with the appropriate diagnostic
tool capable of reading fault codes from the GSBC
Central ECU.
2. Save a diagnostic report to document the state of
the vehicle as it arrived.
3. If a specific DTC (or a list of DTCs) are listed as
“active” faults in the brake controller, use the listed
code in either the diagnostic tool, or the related
Bendix Service Data Sheet documentation, to
identify the correct steps for troubleshooting and
repairing the fault. See Table 17 for a list of related
GSBC and GSAT Service Data Sheets.
NOTE: If a DTC is listed as “inactive,” it is not
currently causing the system to fault. While it
may be indicative of an intermittent problem, it is
extremely difficult to troubleshoot and diagnose
faults that are not active. The technician should
focus their efforts on identifying and correcting
active faults before troubleshooting inactive faults.
4. If the active DTC(s) requires replacement of a
specific component, refer to the Diagnostic Trouble
Code (DTC) and Service Information section of this
document for more information.

Most GSBC components utilize Metric Straight Thread
with o-ring fittings per ISO 4039-2. These fittings are
NOT COMPATIBLE with NPT (National Pipe Taper)
threaded fittings. Additionally, there are other metric
straight thread with o-ring thread design standards. Be
sure to only use fittings that adhere to ISO 4039-2, as
other metric threaded fittings are not cross-compatible.
Use of NPT fittings, or the improper metric fittings,
could result in excessive leakage, damage to threaded
components, improper operation, or even mandatory
replacement of components due to thread damage or
failure.

RELATED GSBC AND GSAT SERVICE DATA
SHEETS
The following documents are available on B2Bendix.com.
COMPONENT/SYSTEM

DOCUMENT NUMBER

GSBC System

This Document

ECU (EBS-90)

This Document

FBM-40

SD-27-5028

EPM-90

SD-27-5031

eTPCM-90

SD-27-5036

M-50QR

SD-27-5170

SAS-80

SD-27-4709

WS-24

SD-13-4860

GSAT System

SD-24-250V

Table 17 – Related Service Data Sheets

SD-27-5023V Rev 002 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

25

Troubleshooting

DIAGNOSTIC TROUBLE CODE (DTC) AND
SERVICE INFORMATION
The GSBC system and Bendix ACom Diagnostic Software
retain a record of all DTCs. This record is commonly
referred to as “event history.” When a DTC self-heals or
is manually cleared, the DTC remains in event history as
an inactive DTC.

BENDIX TECHNICAL SUPPORT
The Bendix Tech Team is available via email at
techteam@bendix.com and by phone at 1-800-AIR-BRAKE
(1-800-247-2725), option 2, Monday through Thursday,
8:00 a.m. to 6:00 p.m. and Friday, 8:00 a.m. to 5:00 p.m. ET.
Follow the instructions in the recorded message.

The GSBC system is supported by Bendix ACom Diagnostic
Software. Visit B2Bendix.com for additional information or
to purchase ACom Diagnostic Software.
Bendix ACom Diagnostic Software supports all DTCs for
Bendix products. For additional troubleshooting support,
go to B2Bendix.com > Services & Support > Diagnostic
Trouble Code Search.

RELATED TECHNICAL DOCUMENTATION REFERENCE
Go to B2Bendix.com to download the latest version of related technical documentation.
DOCUMENT #
BW8207

DOCUMENT TITLE
GSBC Operator’s Manual

SD-27-5028

GSBC FBM-40 Service Data Sheet

SD-27-5031

GSBC EPM-90 Service Data Sheet

SD-27-5036

GSBC eTPCM-90 Service Data Sheet

SD-27-5170

GSBC M-50QR Service Data Sheet

SD-13-4860

Bendix WS-24 Antilock WSS Service Data Sheet

SD-27-4709

Bendix SAS Service Data Sheet

SD-24-250V

GSAT System Service Data Sheet

Any references in this document to VOLVO are solely for identification and cross reference purposes.
The trademarks are the property of their respective companies.
Unless otherwise indicated, the trademarks used in this document, including Bendix, are United States trademarks
owned by, or licensed to, Bendix Commercial Vehicle Systems LLC.

SD-27-5023V Rev 002 © 3/2026 Bendix Commercial Vehicle Systems LLC, a member of Knorr-Bremse • All Rights Reserved