SD-31-7570
Bendix® iSense™ Pro Air Disc Brake (ADB) Continuous
Wear-Sensing Electronic Control Unit (ECU) for TRAILERS
This document covers the
iSense Pro ECU for Trailers*

*Refer to SD-31-70082 on B2Bendix.com for information related to the
tractor iSense and iSense Pro ECU.

The driver is always responsible for the control and
safe operation of the vehicle at all times. The Bendix
wear-sensing ECU does not replace the need for a
skilled, alert, professional driver, performing pre-trip
inspections, reacting appropriately and in a timely
manner, and using safe driving practices. Wear-sensing
ECUs do not remove the need to perform normal
inspections and perform preventative maintenance.

INTRODUCTION
The Bendix® iSense™ Pro Air Disc Brake (ADB) Continuous
Wear-Sensing Trailer Electronic Control Unit (ECU) is a
device designed to help improve the brake pad and rotor
life-monitoring ability of vehicles equipped with Bendix
trailer ADBs.
The ADB ECU uses wear sensors to actively monitor the
wear life remaining percentage of each wheel-end as a
combined measurement of the inboard pad, outboard pad,
and rotor. The ADB ECU can monitor continuous wear
sensors on up to eight (8) wheel-ends on a single vehicle.

IMPORTANT
Wear sensing does not replace routine inspections.
Routine inspections should always be conducted.
Refer to SD-23-7541, Bendix® ADB22X®, ADB22X-V™
and ADB22X®-LT Air Disc Brakes, on B2Bendix.com
for further inspection details.

HARDWARE CONFIGURATION
The ADB wear-sensing ECU is designed to work on a 12volt system and is compatible with 250k and 500k baud
rate J1939 CAN buses.

ECU MOUNTING
The ADB wear-sensing ECU can be mounted within the
trailer box or on the frame and is compatible with continuous
wear sensors. The ECU connector should be installed only
by hand until it clicks into place. The ECU has two (2)
through-hole mounting tabs to be used for mounting; please
refer to OE documentation regarding mounting methods
and torques.

Figure 1 – ADB Wear-Sensing ECU

Bendix wear-sensing ECUs are designed to be warningonly devices. The information broadcast by the ECU
shall not be used to make adjustments to the braking
characteristics of the vehicle.

To ensure the product performs as intended and to prevent
corrosion, all unused wire slots in the ECU connectors
must be plugged and receive any necessary protection
from moisture, etc. The ADB wear-sensing ECU utilizes a
connector from the Deutsch DT product family.

1

GENERAL SAFETY GUIDELINES

WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS
TO AVOID PERSONAL INJURY OR DEATH:

When working on or around a vehicle, the following guidelines should be observed AT ALL TIMES:
▲ Park the vehicle on a level surface, apply the ▲ Never connect or disconnect a hose or line
parking brakes, and always block the wheels.
containing pressure; it may whip and/or cause
Always wear personal protection equipment.
hazardous airborne dust and dirt particles. Wear
eye protection. Slowly open connections with
▲ Stop the engine and remove the ignition key
care, and verify that no pressure is present. Never
when working under or around the vehicle.
remove a component or plug unless you are
When working in the engine compartment,
certain all system pressure has been depleted.
the engine should be shut off and the ignition
key should be removed. Where circumstances ▲ Use only genuine Bendix ® brand replacement
require that the engine be in operation, EXTREME
parts, components, and kits. Replacement
CAUTION should be used to prevent personal
hardware, tubing, hose, fittings, wiring, etc.
injury resulting from contact with moving,
must be of equivalent size, type, and strength as
rotating, leaking, heated, or electrically charged
original equipment and be designed specifically
components.
for such applications and systems.
▲ Do not attempt to install, remove, disassemble, ▲ Components with stripped threads or damaged
or assemble a component until you have read,
parts should be replaced rather than repaired.
and thoroughly understand, the recommended
Do not attempt repairs requiring machining or
procedures. Use only the proper tools and
welding unless specifically stated and approved
observe all precautions pertaining to use of those
by the vehicle and component manufacturer.
tools.
▲ Prior to returning the vehicle to service, make
certain all components and systems are restored
▲ If the work is being performed on the vehicle’s
to their proper operating condition.
air brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure ▲ For vehicles with Automatic Traction Control
from all reservoirs before beginning ANY work
(ATC), the ATC function must be disabled (ATC
on the vehicle. If the vehicle is equipped with
indicator lamp should be ON) prior to performing
a Bendix ® AD-IS® air dryer system, a Bendix ®
any vehicle maintenance where one or more
DRM™ dryer reservoir module, a Bendix® AD-9si®,
wheels on a drive axle are lifted off the ground
AD-HF®, or AD-HFi® air dryer, be sure to drain the
and moving.
purge reservoir.
▲ The power MUST be temporarily disconnected
▲ F o l l o w i n g t h e v e h i c l e m a n u f a c t u r e r ’s
from the radar sensor whenever any tests USING
recommended procedures, deactivate the
A DYNAMOMETER are conducted on a vehicle
electrical system in a manner that safely removes
equipped with a Bendix® Wingman® system.
all electrical power from the vehicle.
▲ Never exceed manufacturer’s recommended
pressures.
▲ You should consult the vehicle manufacturer's operating and service manuals, and any related literature,
in conjunction with the Guidelines above.

2

SOFTWARE CONFIGURATION

CONTINUOUS WEAR SENSOR

Bendix Air Disc Brake (ADB) wear-sensing Electronic
Control Units (ECUs) are not re-configurable and are sold
with a pre-configured software set that is identified by a
part number. Refer to B2Bendix.com.

Continuous wear sensors provide a combined measurement
(as a percentage) of the inboard and outboard brake pads
plus the rotor remaining on each ADB. The sensor is
incorporated into the ADB for wear sensing from the factory.
The calibrated wear sensor provides a voltage output to
the ECU. This signal is then converted to a percentage
and broadcast over the J1939 CAN bus. The continous
wear sensor functions on a 5V supply voltage. If the sensor
outputs a voltage signal of less than 4V, the brake wear
life remaining is in the “good” range. If the sensor outputs
a voltage signal of greater than or equal to 4V, the brake
wear life remaining is considered to be “worn.”

®

ELECTRONIC CONTROL UNIT (ECU) INPUTS
AND OUTPUTS
The ADB wear-sensing ECU has one (1) ignition and one
(1) ground input and is designed to operate at a nominal
supply voltage of 12 volts. The ignition input is the power
source for the ECU and should be supplied through a
5-amp fuse. The operating voltage range is 9.0 to 18.0
VDC. NOTE: ECU operation is not guaranteed outside of
the operating range.

ECU WIRING HARNESS

IMPORTANT
This sensor does not substitute routine inspection
and maintenance.

Bendix does not provide the wiring harness that connects to
the ECU. It is the responsibility of the vehicle manufacturer
to incorporate the wear-sensing ECU wiring harness
into their vehicle harness. The minimum wire gauge for
connectors is 20 AWG. The ECU connector should be
secured by hand until the connector clicks into place.
Refer to the Troubleshooting: Electronic Control Unit (ECU)
Wiring Harness Connectors section of this document.

NOTE: Request of ADB wear sensing must be specified
at the time of order, as continuous wear sensors cannot
be installed after the caliper has already been assembled.

SENSOR POWER AND GROUND

Refer to Table 5 for further information on SPN/FMI.

The ECU supplies three (3) 5-volt power and ground
outputs to be utilized by the continuous wear sensor. Refer
to Table 2.

SAE J1939 SERIAL COMMUNICATIONS
A Controller Area Network (CAN) data link (SAE J1939) is
provided for communication. This link is used for various
functions, including broadcasting the brake pad and rotor
life remaining and circuit diagnostic messages.
The wear-sensing ECU utilizes SAE J1939 CAN protocol
to communicate brake pad and rotor wear status. The
ECU utilizes PGN 64512 - Trailer Wheel Brake Wear Life
Remaining Information message to broadcast brake pad
and rotor wear information.

COMMUNICATION
The ADB wear-sensing ECU can utilize all eight (8) SPNs
of PGN 64512 correlating to trailer axle #1-#4 depending
on the ECU axle configuration. Refer to Table 1.

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 or video
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.

DIAGNOSTIC TROUBLE CODES (DTCs)
FOR CONTINUOUS WEAR SENSORS
If an issue is detected with one of the continuous wear
sensors, a DTC will be broadcast to indicate what kind
of failure that sensor is experiencing. All other wear
sensors should maintain normal function. Refer to the
Troubleshooting section for more information.

3

PGN

64512

65216

PARAMETER
GROUP
LABEL

Trailer Wheel
Brake Wear
Life Remaining
Information

Service
Information

ECU AXLE CONFIGURATION
ACRONYM

TWBW

SERV

SPN

SPN LABEL

DATA RANGE

1
AXLE

2
AXLE

3
AXLE

4
AXLE

22754

Brake Wear Life Remaining,
Trailer Axle #1, Left Wheel

0% to 100%

X

X

X

X

22755

Brake Wear Life Remaining,
Trailer Axle #1, Right Wheel

0% to 100%

X

X

X

X

22756

Brake Wear Life Remaining,
Trailer Axle #2, Left Wheel

0% to 100%

X

X

X

22757

Brake Wear Life Remaining,
Trailer Axle #2, Right Wheel

0% to 100%

X

X

X

22758

Brake Wear Life Remaining,
Trailer Axle #3, Left Wheel

0% to 100%

X

X

22759

Brake Wear Life Remaining,
Trailer Axle #3, Right Wheel

0% to 100%

X

X

22760

Brake Wear Life Remaining,
Trailer Axle #4, Left Wheel

0% to 100%

X

22761

Brake Wear Life Remaining,
Trailer Axle #4, Right Wheel

0% to 100%

X

22762

Brake Wear Life Remaining,
Trailer Axle #5, Left Wheel

0% to 100%

22763

Brake Wear Life Remaining,
Trailer Axle #5, Right Wheel

0% to 100%

22764

Brake Wear Life Remaining,
Trailer Axle #6, Left Wheel

0% to 100%

22765

Brake Wear Life Remaining,
Trailer Axle #6, Right Wheel

0% to 100%

22766

Brake Wear Life Remaining,
Trailer Axle #7, Left Wheel

0% to 100%

22767

Brake Wear Life Remaining,
Trailer Axle #7, Right Wheel

0% to 100%

22768

Brake Wear Life Remaining,
Trailer Axle #8, Left Wheel

0% to 100%

22769

Brake Wear Life Remaining,
Trailer Axle #8, Right Wheel

0% to 100%

911

Service Component Identification
Service Component Identification

Not Broadcast
(or 15)

X

X

X

X

Table 1 – Communication

DRIVER WARNING DEVICES
Individual Original Equipment Manufacturers (OEMs)
are responsible for integrating this information into their
dash. OEMs shall follow those rules laid out in Federal
Motor Vehicle Safety Standards (FMVSS) for warning light
operation, symbol, and color for brake pad and rotor wear.

4

IMPORTANT
The ADB wear-sensing ECU may broadcast the “Service
Component Identification” message with the number
“15” if any wheel position is below 10% life remaining
or there is a Diagnostic Trouble Code (DTC) present.
That message will not stop broadcasting until all wheel
positions are above 15% life remaining and there are
no DTCs active.

TROUBLESHOOTING
REMOVING THE BENDIX® AIR DISC BRAKE
(ADB) WEAR-SENSING ELECTRONIC
CONTROL UNIT (ECU)
1. Turn the vehicle ignition off.
2. Remove as much contamination as possible prior to
disconnecting the electrical connections.
3. Note the Electronic Control Unit (ECU) assembly
mounting position on the vehicle.

ECU DIAGNOSTICS
The ADB wear-sensing ECU contains self‑testing diagnostic
circuitry that continuously checks for the normal operation
of external wear-sensing ECU components and wiring.

ACTIVE DIAGNOSTIC TROUBLE
CODES (DTCs)

4. Disconnect the electrical connector from the ECU.

When a DTC is detected, the ADB wear-sensing ECU
performs the following:

5. Remove and retain the mounting bolts that secure
the ECU.

1. The ECU places the appropriate DTC information in
the ECU memory.

INSTALLING A NEW BENDIX ADB WEARSENSING ECU

When replacing the ADB wear-sensing ECU, verify
that the unit you are installing has the correct default
settings.
Verify correct operation of the ADB wear-sensing ECU
by evaluating the system function with Bendix ® ACom®
Diagnostic Software. Refer to the section titled Using
PC-based Diagnostics in this document.
For further information, contact either the vehicle