Figure 20 – Removing the EPM Silencer
3. Lift the cover and silencer element from the EPM.

18

SD-27-5031 Rev 001 Bendix® GSBC® EPM-90™ (Global Scalable Brake Control Electro-Pneumatic Modulator)

REPLACEMENT INSTRUCTIONS (CONT.)
SILENCER INSTALLATION
To install a silencer on the EPM, follow these steps:

2. While keeping pressure on the silencer, looking at
the exhaust port, rotate it clockwise to bring the
retention tab over the locking point. See Figure 22.

1. Place the new silencer on the EPM aligning the
locking tabs between the slots on the body casting.
NOTE: Be careful not to allow the mesh to fall out
of the silencer housing during installation.

Figure 22 – Securing Silencer Retention Tab

Figure 21 – Replacing the EPM Silencer

SD-27-5031 Rev 001 Bendix® GSBC® EPM-90™ (Global Scalable Brake Control Electro-Pneumatic Modulator)

19

MAINTENANCE

CLEANING AND INSPECTION (CONT.)

The EPM does not need to be removed from the vehicle
for maintenance of serviceable parts. Proper installation
allows for sufficient clearance around the part. However,
the part may be removed if necessary for maintenance of
serviceable parts.

CLEANING (CONT.)

IMPORTANT
Review the Bendix Warranty Policy before performing any
intrusive maintenance procedures. A warranty may be
voided if intrusive maintenance is performed during the
warranty period. No two vehicles operate under identical
conditions, as a result, maintenance intervals may vary.
Experience is a valuable guide in determining the best
maintenance interval for air brake system components.
At a minimum, the EPM should be inspected every
6 months or 1500 operating hours, whichever comes
first, for proper operation. Should the EPM not meet
the standards of the operational tests noted in this
document, further investigation may be required.

IMPORTANT
The EPM is designed not to require maintenance, and
there are no user-serviceable components located
inside the EPM. Disassembly of the device will void
the component warranty, and Bendix will not provide
technical support or replacement components for
components internal to the EPM.

CLEANING AND INSPECTION
CLEANING
Clean the exterior of the EPM and remove debris and
contamination.
he preferred method for cleaning the EPM of dirt, grit,
T
salt, or other build-up is water with a gentle brush. It is
permissible to use a gentle detergent, but strong acid or
chemical cleaners should be avoided. It is also permissible
to use a pressure washer, but the technician should
be careful not to hold the pressure washer close to the
EPM, use excessive pressure, or spray water directly at
the exhaust port(s), electrical connectors, or Electrical
Covering Cap(s).

20

Be cautious while using a pressure washer to clean
components. Appropriate Personal Protective
Equipment (PPE) is recommended (e.g., eye protection)
while using a pressure washer. Failure to use PPE
could result in personal injury. Rubber parts, sealing
interfaces, and electrical components or covers should
not be directly sprayed with the high-pressure jet.
Failure to follow maintenance procedures could lead
to serious vehicle braking, instability, and performance
issues, and/or collisions causing property damage,
serious injuries, and/or death.
INSPECTION
To inspect an EPM, ensure that the following conditions
are met:
1. Confirm that all harness connectors are properly
plugged and secured.
2. If there is an unused X3 connector, confirm that
the connector is covered with a dust plug.

IMPORTANT
The X3 connector is not used on all vehicles. If not
plugged into the vehicle harness, the X3 connector
should be covered with a dust plug. Failure to do so
may lead to corrosion of the pins which may cause
issues and eventual EPM failure. Contact the OEM for
dust plug ordering information.
The X4 connector does not require a dust cover as it
is an unused connector without pins.
3. Confirm that the electrical connector covers are
properly plugged and secured.
4. Confirm that the silencer(s) on the exhaust
port(s) (port 3) are clean and free of debris. See
Figures 6 and 7 starting on page 4.
5. Confirm that all the fittings are intact and there are
no signs of excessive corrosion.
6. Confirm that all air lines are intact and not cracked,
damaged, or worn.

SD-27-5031 Rev 001 Bendix® GSBC® EPM-90™ (Global Scalable Brake Control Electro-Pneumatic Modulator)

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 code remains in event history as an inactive
DTC.
The GSBC system is supported by Bendix ACom Diagnostic Software. Visit B2Bendix.com for additional information or
to purchase ACom Diagnostic Software.

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.

DTC #

SPN
(J1939)

FMI
(J1939)

DTC NAME

DTC DESCRIPTION

GO TO
SERVICE
ACTION CODE
LISTED IN
TABLE 9

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.

A

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.

B

0x506718

20583

24

Wheel 1 EPM: Circuit Current
Below Threshold

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

C

0x506764

20583

100

Wheel 1 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

D

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.

A

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.

B

0x506818

20584

24

Wheel 2 EPM: Circuit Current
Below Threshold

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

C

0x506864

20584

100

Wheel 2 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

D

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.

A

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.

B

0x506918

20585

24

Wheel 3 EPM: Circuit Current
Below Threshold

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

C

0x506964

20585

100

Wheel 3 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

D

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.

A

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.

B

0x506A18

20586

24

Wheel 4 EPM: Circuit Current
Below Threshold

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

C

0x506A64

20586

100

Wheel 4 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

D

Table 8 - Diagnostic Trouble Codes (DTCs)
SD-27-5031 Rev 001 Bendix® GSBC® EPM-90™ (Global Scalable Brake Control Electro-Pneumatic Modulator)

21

DIAGNOSTIC TROUBLE CODE (DTC) AND SERVICE INFORMATION (CONT.)

DTC #

SPN
(J1939)

FMI
(J1939)

DTC NAME

DTC DESCRIPTION

GO TO
SERVICE
ACTION CODE
LISTED IN
TABLE 9

0x506B12

20587

18

Wheel 5 EPM: Circuit Short
To Battery

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

A

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.

B

0x506B18

20587

24

Wheel 5 EPM: Circuit Current
Below Threshold

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

C

0x506B64

20587

100

Wheel 5 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

D

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.

A

0x506C14

20588

20

Wheel 6 EPM: Circuit Short
To Ground or Open

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

B

0x506C18

20588

24

Wheel 6 EPM: Circuit Current
Below Threshold

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

C

0x506C64

20588

100

Wheel 6 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

D

0x506D12

20589

18

Wheel 7 EPM: Circuit Short
To Battery

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

A

0x506D14

20589

20

Wheel 7 EPM: Circuit Short
To Ground or Open

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

B

0x506D18

20589

24

Wheel 7 EPM: Circuit Current
Below Threshold

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

C

0x506D64

20589

100

Wheel 7 EPM: Signal
Plausibility Failure

Sensor frequency is out of the specified ranges.

D

0x506E12

20590

18

Wheel 8 EPM: Circuit Short
To Battery

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