CC

Clear DTC. If fault returns, then check for shorts to ground or battery in lining wear harness. If there
are no faults found in the harness, check the lining wear sensor for proper operation. Replace the
lining wear sensor if it is not functioning properly or if it is damaged. If the fault is still present after
these steps, replace the EPM connected to the faulted lining wear sensor.

DD

Check brake actuators and pads. Replace worn parts.

EE

The system has detected brake imbalance between two sides of the same axle. Inspect all
foundation brake components on both sides of the axle, looking for signs of uneven brake wear side
to side. Correct any mechanical faults with the foundation brakes, and additionally inspect the air
lines between the EPM and the foundation brakes, looking for kinked, damaged, or obstructed air
lines. Repair or replace as necessary.

FF

The WSS cables are reversed at the EPM connector of an axle (for example, the left side sensor
cable is connected to the right side sensor connector, and the right side sensor cable is connected to
the left side sensor connector). Inspect EPM and swap specified sensors across the axle.
If the sensors are correct or cannot be moved, the dataset will need to be updated to reflect the
hardware configuration. Contact the vehicle OEM for assistance in updating the dataset.

GG

No action needed. This is not a fault but an indicator of the active Dyno Mode.

HH

Check vehicle wiring. Check if there is an additional unconfigured EPM connected to the GSBC
Central ECU. Compare vehicle configuration to original (factory) configuraiton. If changes have been
made to the vehicle after it was built, consult the OEM for assistance in updating vehicle configuration
in GSBC Central ECU.

JJ

Check battery voltage. If battery voltage is outside OEM specifications, repair vehicle charging
system per OEM instructions. Check wiring from battery to the ECU. Ensure voltage difference
between ECU supply and ground pins (X1:7 to X1:15, and X1:8 to X1:16) is within specification.
Clear fault. If fault returns, replace the ECU.

KK

Internal 10V power supply is out of range. Check battery voltage. If battery voltage is outside OEM
specifications, repair vehicle charging system per OEM instructions. Check wiring from battery to the
ECU. Ensure voltage difference between ECU supply and ground pins (X1:7 to X1:15, and X1:8 to
X1:16) is within specification. Clear fault. If fault returns replace the ECU
Check and inspect the foundation brakes for signs of overheating. If brakes have overheated, make
any repairs necessary and inform the driver.

LL

MM

If no signs of overheating are found, check vehicle data bus and parameter file for inaccurate or
missing information regarding: time/date, wheel speed, brake pressure, ambient temperature, and
threshold pressure. Any incorrect, corrupted, or missing configuration values or changes to the
vehicle’s physical configuration can cause brake energy (and heat estimated brake temperature) to
be calculated incorrectly.
Imbalanced brake performance (left to right) has been detected. Check for uneven brake wear across
all axles. Inspect foundation brake components, brake adjustment, brake hoses, and suspension
components.

Table 19 – GSBC System/ECU Service Action Codes

46

SD-27-5023V Rev 000 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

Troubleshooting
SERVICE
ACTION CODE

RECOMMENDED SERVICE ACTION
The system has detected an implausibly long ABS event.
First, using diagnostic software, graph each wheel speed sensor individually while turning that wheel,
and inspect for proper response and consistency between wheel ends.

NN

Next, confirm that the system is parameterized properly. Check and confirm that the following
parameters are set correctly in the ECU and that the vehicle has not been modified since leaving the
factory:
•
Tire size
•
Tire Static Loaded Radius (SLR)
•
Tone wheel tooth count
•
WSS configuration (ensure that each sensor is located in the correct location)
•
Axle configuration (ensure that the vehicle is properly parameterized for steer, driven and
liftable axles)
•
Confirm that each EPM delivery is going to the correct wheel end (and that hoses are not
switched across an axle)
If a parameter does not match the vehicle, correct the configuration values or change the part of the
vehicle. For configuration information, contact OEM.
Finally, if the GSBC Central ECU parameterization is correct, physically inspect the vehicle for the
following:
•
Check that the pneumatic air lines and components are operating properly and not
obstructed
•
Check that the foundation brakes are in good repair and not damaged or excessively worn
•
Check the WSSs for damage and appropriate gap from the tone wheel
•
Check the tone wheels for damage or debris

PP

Clear DTC and reset ECU. Check other ECUs on vehicle for failures or correct function. Inspect
J1939 CAN for damage, shorts, opens, or incorrect operation, including chafing damage.
If no other faults are found and everything else is operating normally, replace the GSBC Central ECU.
Missing CAN messages. Clear DTC and reset ECU.

QQ

Inspect electrical connectors at the GSBC Central ECU and the ECU with missing messages for
damage, corrosion, or shorted connectors. If damage is found, repair or replace the damage as
necessary.
Inspect CAN wiring for damage, shorts, opens, or incorrect operation, including chafing damage.
Check other ECU for proper operation; contact OEM for additional assistance.

RR

SS

Clear DTC and reset ECU. Check and eliminate contact failures at the connectors of Steer Angle
Sensor (SAS) and GSBC Central ECU. Inspect CAN wiring for damage, shorts, opens, or incorrect
operation, including chafing damage. If other CAN devices are working normally, replace SAS.
Clear DTC and reset ECU. Check other ECUs on vehicle for failures or correct function. Inspect CAN
wiring for damage, shorts, opens, or incorrect operation, including chafing damage. Check that GSBC
Central ECU is getting good power from the vehicle.
Confirm that there are no other active CAN faults before proceeding. If wiring is OK and failure is still
present, replace the GSBC Central ECU.

TT

Replace PLC Relay.

UU

If vehicle is equipped with an axle load sensor, check sensor operation per OEM guidelines. Check
that GSBC Central ECU parameters regarding vehicle weight are correct. Check that vehicle has
not been modified since leaving the factory. For help in updating GSBC Central ECU configuration to
reflect vehicle changes, contact vehicle OEM.

VV

Check that the configuration of the tire circumference in the GSBC Central ECU parameter settings
matches the circumference of the mounted tire. Correct that value if it is incorrect. Reset GSBC selflearned wheel circumferences.
Inspect the WSSs and tone rings for damage or wear. Confirm that the tone ring tooth count settings
in the GSBC Central ECU is correct and matches the tone rings installed on the vehicle.

XX

Vehicle did not decelerate within expected bounds. Check vehicle for problems leading to reduced
braking. Check for sufficient supply pressure, faded brakes or signs of overheated brakes,
overloaded vehicle and/or trailer, check pneumatic plumbing for restrictions and other obstructions.
Check and inspect foundation brakes for proper maintenance and operation.

YY

Large number of active faults. Check the active faults and correct them.

Table 19 – GSBC System/ECU Service Action Codes

SD-27-5023V Rev 000 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

47

Troubleshooting
SERVICE
ACTION CODE

RECOMMENDED SERVICE ACTION

ZZ

Switch ignition off. Disconnect Vehicle CAN from GSBC Central ECU and wait 15s. Reconnect
Vehicle CAN to GSBC Central ECU and switch ignition on. If the fault clears, check for unexpected/
improper CAN communication from other ECUs while ignition is off. If no other ECUs are active while
ignition is off, replace GSBC Central ECU.

AAA

Resetting the ECU should clear the DTC. If the DTC comes back, reflash the GSBC Central ECU
software. Contact the vehicle OEM for software and assistance.

BBB

Turn off the vehicle. Inspect the GSBC Central ECU connector with the GND1 and GND2 pins.
Confirm that the electrical connector and wires are not damaged, corroded, shorted, or open. Confirm
that the wires connected to GND1 and GND2 are connected to chassis ground. Repair any problems
discovered per OEM recommendations.
Turn the vehicle back on. Check that there is ~0V difference between GND1 and GND2 pins. Reset
GSBC Central ECU. If the problem is still present, replace GSBC Central ECU.

CCC

The GSBC Central ECU is over temperature (above 248°F [120°C]). Power off the vehicle and wait
for the vehicle to cool down. If the vehicle has cooled down and the fault is still active, replace the
GSBC Central ECU.

DDD

Replace valves that have exceeded lifetime cycle limit(s) and reset the counter with diagnostic tool.

EEE

Switch ignition off. Disconnect Vehicle CAN from GSBC Central ECU and wait 15s. Reconnect
Vehicle CAN to GSBC Central ECU and switch ignition on. If the fault clears, check for unexpected/
improper CAN communication from other ECUs while ignition is off. If no other ECUs are active while
ignition is off, replace GSBC Central ECU.

FFF

Replace ECU if DTC still active after multiple ignition on-off cycles.

GGG

The GSBC Central ECU is under temperature (below -35°F [-37°C]). If the vehicle has been warmed
above that temperature and the fault is still active, replace the ECU.
If the state is active continuously, check vehicle’s power supply system. Measure voltage between
pins X1/15 and X1/7.
Voltage is out of range for electronic pressure control if supply voltage is lower than 15V or higher
than 36V.

HHH

Voltage is out of range for keeping the EPMs switched on if supply voltage is lower than 10V for at
least 40ms or higher than 36V for 380ms.
Voltage is out of range for controlling the eTPCM and modulators if supply voltage is not between
19V-32V.
If battery voltage at GSBC Central ECU connectors is correct and within normal range, replace ECU.

Table 19 – GSBC System/ECU Service Action Codes

48

SD-27-5023V Rev 000 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

Troubleshooting

GSBC EPM-90 DTCS
IMPORTANT
For all repair steps, first complete the following:
1. Generate an ACom Diagnostic Software report.
2. Clear DTCs.
3. Continue with repair information for each active DTC that will not clear.
NOTE: After completing all repairs, drive the vehicle to ensure the repairs were sufficient.
4. Once repairs have been made, clear the DTC again.

SD-27-5031, AVAILABLE ON B2BENDIX.COM
GSBC EPM-90 DTCS
DTC #

SPN
(J1939)

FMI
(J1939)

DTC NAME

DTC DESCRIPTION

SD SHEET

0x506712

20583

18

Wheel 1 EPM: Circuit Short
To Battery

Internal WSS Analog signals are not in valid
range. Short to Battery detected at high side or
low side.

SD-27-5031

0x506714

20583

20

Wheel 1 EPM: Circuit Short
To Ground or Open

Hardware fault detected inside EPM. Short to
Gnd detected at high side or low side.

SD-27-5031

0x506718

20583

24

Wheel 1 EPM: Circuit Current
Below Threshold

Hardware fault detected inside EPM. Sensor
not connected or High side/Low side open.

SD-27-5031

0x506764

20583

100

Wheel 1 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

SD-27-5031

0x506812

20584

18

Wheel 2 EPM: Circuit Short
To Battery

Internal WSS Analog signals are not in valid
range. Short to Battery detected at high side or
low side.

SD-27-5031

0x506814

20584

20

Wheel 2 EPM: Circuit Short
To Ground or Open

Hardware fault detected inside EPM. Short to
Gnd detected at high side or low side.

SD-27-5031

0x506818

20584

24

Wheel 2 EPM: Circuit Current
Below Threshold

Hardware fault detected inside EPM. Sensor
not connected or High side/Low side open.

SD-27-5031

0x506864

20584

100

Wheel 2 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

SD-27-5031

0x506912

20585

18

Wheel 3 EPM: Circuit Short
To Battery

Internal WSS Analog signals are not in valid
range. Short to Battery detected at high side or
low side.

SD-27-5031

0x506914

20585

20

Wheel 3 EPM: Circuit Short
To Ground or Open

Hardware fault detected inside EPM. Short to
Gnd detected at high side or low side.

SD-27-5031

0x506918

20585

24

Wheel 3 EPM: Circuit Current
Below Threshold

Hardware fault detected inside EPM. Sensor
not connected or High side/Low side open.

SD-27-5031

0x506964

20585

100

Wheel 3 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

SD-27-5031

0x506A12

20586

18

Wheel 4 EPM: Circuit Short
To Battery

Internal WSS Analog signals are not in valid
range. Short to Battery detected at high side or
low side.

SD-27-5031

0x506A14

20586

20

Wheel 4 EPM: Circuit Short
To Ground or Open

Hardware fault detected inside EPM. Short to
Gnd detected at high side or low side.

SD-27-5031

0x506A18

20586

24

Wheel 4 EPM: Circuit Current
Below Threshold

Hardware fault detected inside EPM. Sensor
not connected or High side/Low side open.

SD-27-5031

0x506A64

20586

100

Wheel 4 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

SD-27-5031

Table 20 - GSBC EPM-90 Diagnostic Trouble Codes (DTCs)

SD-27-5023V Rev 000 Bendix® GSBC® System and EBS-90™ (Global Scalable Brake Control System and Electronic Control Unit)

49

Troubleshooting

GSBC EPM-90 DTCS
DTC #

SPN
(J1939)

FMI
(J1939)

DTC NAME

DTC DESCRIPTION

SD SHEET

0x506B14

20587

20

Wheel 5 EPM: Circuit Short
To Ground or Open

Hardware fault detected inside EPM. Short to
Gnd detected at high side or low side.

SD-27-5031

0x506B18

20587

24

Wheel 5 EPM: Circuit Current
Below Threshold

Hardware fault detected inside EPM. Sensor
not connected or High side/Low side open.

SD-27-5031

0x506B64

20587

100

Wheel 5 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

SD-27-5031

0x506C12

20588

18

Wheel 6 EPM: Circuit Short
To Battery

Internal WSS Analog signals are not in valid
range. Short to Battery detected at high side or
low side.

SD-27-5031

0x506C14

20588

20