SD-13-47672A

®

Bendix® TABS‑6™ Advanced Multi-Channel (MC) Trailer ABS Module Generation 2
Electronic Control Unit (ECU)
Cover (Sealed)
Mounting Studs

Wheel Speed
Sensor (WSS)
Connectors

For Part Label Information,
See Page 58

Lockable ECU Connector
Covers on Both Sides
(removable)
12-Pin
Connector
7-Pin
Connector

For Port
Descriptions,
See Page 3

Mounting
Studs

Wheel Speed
Sensor (WSS)
Connectors

Figure 1 – Bendix ® TABS‑6™ Advanced Multi-Channel (MC) Antilock Braking System (ABS) Module

1. INTRODUCTION
The Bendix® TABS‑6™ Advanced Multi-Channel (MC) module
(Generation 2) is an integrated, MC (4S/2M) trailer service
brake module controller for air-braked, heavy-duty semi trailers
that features the Bendix® Antilock Brake System (ABS) and
Bendix® Trailer Roll Stability Program (TRSP®).
Installed on semi-trailers, the module acts as a relay valve
during normal braking, but during ABS events, it will intervene
to help maintain vehicle stability and minimize stopping distance
by preventing wheel lock-up. The Bendix TRSP monitors the
trailer's motion and reduces the risk of rollovers by automatically
applying the brakes when a risk of a rollover is detected.
This module features:
•

modular design with an integrated Electronic Control Unit
A
(ECU); pressure sensors; a lateral acceleration sensor;
and Modulator Relay Valves (MRVs) – eliminating external
pigtail harnesses for these components

•

An operating voltage range of 8 - 32 volts

•

n electronic odometer with trip counters and service
A
interval options

•

scratch-pad feature with up to 1,008 bytes of freely
A
definable read/write text space available for customer use

•

n extended data logging feature, including a resettable
A
drive recorder

Section TABLE OF CONTENTS . . . . . . . . . . . PAGE
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. General Safety Guidelines . . . . . . . . . . . . . . . . . 2
3. Antilock Braking System (ABS) Operation . . . . . 3
4. Bendix® Trailer Roll Stability Program
(TRSP®) Operation . . . . . . . . . . . . . . . . . . . . . . 4
5. Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6. Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7. Pigtail Wiring Harnesses . . . . . . . . . . . . . . . . . . .8
8. Antilock Braking System (ABS) Indicator Lamp . 9
9. Bendix® WS-24™ Wheel Speed Sensors . . . . . . 9
10. SAE J2497 (PLC) Diagnostic Link . . . . . . . . . . 10
11. SAE J1939 (CAN) Diagnostic Link . . . . . . . . . . 10
12. Auxiliary I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
13. Bendix® ABS Flex™ Program . . . . . . . . . . . . . . 11
14. Customer Scratch Pad . . . . . . . . . . . . . . . . . . . 11
15. Power-Up Sequence . . . . . . . . . . . . . . . . . . . . . 11
16. Odometer Function . . . . . . . . . . . . . . . . . . . . . . 12
17. Non-Standard Tire Size . . . . . . . . . . . . . . . . . . 12
18. Diagnostic Trouble Code (DTC) Detection . . . . 13
19. Partial ABS Shutdown . . . . . . . . . . . . . . . . . . . .13
20. Blink Code Diagnostics . . . . . . . . . . . . . . . . . . . 13
21. Auxiliary Features . . . . . . . . . . . . . . . . . . . . . . . 14
22. Diagnostic Trouble Codes (DTCs) . . . . . . . . . . . 17
23. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . 28
1

● A wide variety of electrical inputs/outputs (I/Os) that
allow the customer to program auxiliary functions such
as automatic Lift Axle Control (LAC); Integrated Speed
Switch (ISS); external load sensors; Auxiliary Design
Language (ADL) for customized auxiliary functions; and
others
● A wide range of diagnostic tools for flexible
troubleshooting such as blink codes; SAE J2497 Power
Line Carrier (PLC); SAE J1939 (CAN) diagnostics; the
Bendix® Trailer Remote Diagnostic Unit (TRDU); and
the Bendix® Trailer Information Module

● Support for SAE J2497 PLC communication to the
towing vehicle and diagnostics
● Support for SAE J1939 (CAN) communication for
diagnostics and external devices
● A pressure-equalizing valve in the sealed Electronic
Control Unit (ECU) housing to give improved protection
from water, etc.
● A serviceable nylon filter to help prevent foreign material
from entering the control port
● Locking dust covers to provide electrical connector and
cable protection

2. GENERAL SAFETY GUIDELINES
2. GENERAL
SAFETYGUIDELINES
GUIDELINES
GENERAL
SAFETY

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. must
injury resulting from contact with moving,
be of equivalent size, type and strength as original
rotating, leaking, heated or electrically‑charged
equipment and be designed specifically for such
applications and systems.
components.
▲ 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.
Do not attempt repairs requiring machining or
and thoroughly understand, the recommended
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 a
indicator lamp should be ON) prior to performing
Bendix® AD‑IS® air dryer system, a Bendix® DRM™
any vehicle maintenance where one or more
®
®
dryer reservoir module, a Bendix AD‑9si, AD‑HF ,
wheels on a drive axle are lifted off the ground
™
or AD‑HFi air dryer, be sure to drain the purge
and moving.
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.

Disconnect the electrical connectors from the
Bendix® Antilock Braking System (ABS)/Bendix®
Trailer Roll Stability Program (TRSP®) controller
before welding on the trailer.

2

Dielectric grease should be applied to electrical
connectors to help protect against moisture
intrusion.

3/8-in. NPTF Load Port 42 for Air Suspension
(Plugged for the Bendix® Antliock Braking System (ABS)
only or Spring Suspension Vehicles)

Two 3/8-in. NPTF
Delivery Ports 21
(to Brake Chambers)

3/8-in. NPTF Delivery
Port 21
(to Brake Chambers)

3/8-in. NPTF Control Port 4
with Integral Filter

3/8-in. NPTF Delivery
1/2-in. NPTF Supply
Port 22
Port 1 (Plug Unused (to Brake Chambers)
Port)

Two 3/8-in. NPTF Delivery Ports 22
(to Brake Chambers)

For NPTF fittings, the use of a thread sealant is recommended. This can be a pre-applied or a
hand-applied sealant product (with PTFE) can be used. When using a hand-applied sealant,
use caution so as not to over-apply. Always follow the fitting manufacturer’s pre-applied or
hand-applied thread sealant recommendations. Use of PTFE tape is not approved and will
void the Bendix® ABS/Bendix® Trailer Roll Stability Program (TRSP®) valve warranty.
Figure 2 – Ports Used

3. ANTILOCK BRAKING SYSTEM (ABS)
OPERATION
The Bendix® TABS‑6™ Advanced Multi-Channel (MC)
module uses Wheel Speed Sensors (WSS), Modulator
Relay Valves (MRVs), and an Electronic Control Unit
(ECU) to optimize the contact between the tires and the
road surface during a braking event where excessive wheel
slip – or wheel lock-up – is detected.
When a situation is detected where the system needs
to intervene, the ECU will activate the MRVs to apply
controlled brake pressure at the wheel ends. Depending on
the configuration of the ABS system, interventions may be
made on individual wheels, or pairs of wheels. In the case
of pairs of wheels, the wheels controlled by a modulator
may be either on the same side of the vehicle, or at both
ends of an axle.

Axle control (select high) and side control should
not be used on fifth-wheel dollies or steerable axles.
In these cases, it could cause a yaw moment during
braking that results in unwanted steering of the axle.
Use a dolly control (select low) configuration.
Side Control (Independent Control)
Side control uses a single MRV to separately control the
braking on one (1) or more wheels, on either side of the
vehicle.
In the case of braking surfaces with poor overall traction,
the side control ABS interventions will maintain the wheels
on each side of the vehicle independently, at just under the
speed where they would lock up.

The TABS‑6 Advanced MC module ECU is typically able
to modulate the brake pressure with greater speed and
accuracy than a driver.

NOTE: Side control should not be used on fifth-wheel
dollies or steerable axles.

Normal Braking

Axle control uses a single Modulator Relay Valve (MRV) to
control the wheels at both ends of a given axle (or multiple
axles in cases where a single MRV is controlling several
axles).

During normal braking, the TABS‑6 Advanced MC module
functions as a standard relay valve. If the ECU does not
detect excessive wheel slip, it will not activate the ABS
system, and the vehicle will stop with normal braking.

Axle Control

3

In the case of braking surfaces with poor overall traction
(e.g. roads that are worn, slippery, or are made of loose
gravel) – or braking surfaces with areas of poor traction
(e.g. asphalt roads with patches of ice) – axle control
Antilock Braking System (ABS) interventions will maintain
the wheel that is not slipping at just under the speed that
will lock the wheel. The system permits the other wheel (that
is experiencing slippage) temporary periods of wheel-lock
during the intervention.
Axle control should not be used on fifth-wheel dollies or
steerable axles.
When intervening on regular traction road surfaces, a
system configured for axle control performs similar to a
side-control, two-modulator system.
Steerable Axles
For applications that have both fixed and steerable axles,
such as drawbar trailers (full-pull trailers), a 4S2M axle
configuration should be used. These configurations have
the ability to minimize yaw on steerable axles.

Even with TRSP-equipped vehicles, the driver remains
responsible for ensuring vehicle stability during
operation. The TRSP system only functions within
the limits of physics. The system can help mitigate
potential vehicle stability incidents, but cannot prevent
them in all cases. Other factors – such as driving
too fast for the road, traffic or weather conditions,
over-steering, an excessively high vehicle Center of
Gravity (CG), poor road conditions, or insufficient
vehicle maintenance – can cause vehicle instability
that is beyond the capability of any stability system
to mitigate.

Operating the vehicle with a damaged/disconnected
load sensor could lead to a serious accident. The
advanced ABS system used on this vehicle uses
sensors, including the load sensor, to assist the
TRSP function.

ABS Fail-Safe
The Bendix® TABS‑6™ Advanced Multi-Channel (MC)
module is designed to react in a fail-safe manner in the
event of a system Diagnostic Trouble Code (DTC). For
example, if the Electronic Control Unit (ECU) detects that
a sensor is not responding, an ABS system DTC will be set
and the TABS‑6 Advanced MC module will illuminate the
trailer ABS indicator lamp and revert to a fail-safe mode
where some, or all, advanced ABS functions (including
the Bendix® Trailer Roll Stability Program (TRSP®) may
not function. Even in cases where the ABS system is
completely disabled, the standard pneumatic brake function
of the vehicle will still be available, but without the benefits
of the ABS system. The TRSP feature is also disabled
with an active ABS system DTC. If the indicator lamp is
illuminated, always have the ABS system serviced at the
earliest opportunity
.

4. BENDIX ® TRAILER ROLL STABILITY
PROGRAM (TRSP®) OPERATION

During a TRSP system intervention, the vehicle
automatically decelerates. The TABS‑6 Advanced
MC module can slow the vehicle with or without the
driver applying the brake pedal, and even when the
driver applies the throttle.

4

The TRSP system should only be used on specific
vehicle platforms that have been validated and
approved by Bendix engineering.

For vehicles installed with spring suspension
systems, care must be taken to prevent damage to
the load sensor when lifting the trailer. The linkage
rod must be disconnected from the sensor’s rubber
boot whenever the frame of the trailer is lifted,
dropping the axle(s). This includes situations where
a jack is used on the rear bumper or when a crane is
used to lift the trailer.
The TRSP system reduces the risk of rollovers during
driving by automatic application of the service brakes when
the system detects potential rollover conditions. This is
accomplished with monitoring sensors both at the trailer
wheel ends and within the TABS‑6 Advanced MC module.
The TRSP system reacts by applying the trailer service
brakes and slowing the vehicle combination.

The Bendix® Trailer Roll Stability Program (TRSP®) system
uses the following sensors:
•

ateral Acceleration: A lateral accelerometer is located
L
within the Bendix® TABS‑6™ Advanced Multi-Channel
(MC) module. This sensor detects the lateral motion (or
“roll”) of the vehicle as it moves. The TABS‑6 Advanced
MC module must be mounted either facing forward
(0 degrees) or facing the rear (180 degrees) of the trailer
to function correctly – See the Troubleshooting section
for full details of acceptable installation locations.
NOTE: Do not attempt to change the location of the
module without contacting Bendix for engineering
approval.

•

ehicle Speed: The TRSP system obtains information
V
about the vehicle speed and rate of acceleration from
the Wheel Speed Sensors (WSS).

•

Axle/Bogie Load: The trailer’s axle load information
is obtained either by the use of:
a. An integrated pressure sensor port (P42) of the
TABS‑6 Advanced MC module, where a direct
reading of the suspension air spring pressure is
taken; or
b. If configured for a mechanical spring deflection
sensor, a voltage reading that is proportional to the
spring deflection.

•

rake Demand Pressure Sensor: This sensor
B
monitors the trailer service brake pressure being
applied by the driver and sends an electrical signal
directly proportional to the driver’s brake demand to
the ECU.

•

rake Delivery Pressure Sensors: These sensors
B
(P21 and P22) monitor the trailer service brake pressure
that is being delivered to the wheel ends through, or by,
the TABS‑6 Advanced MC module system and sends
electrical signals directly proportional to the delivered
trailer service brake pressure to the ECU.

•

Internal Load Sensor: For air suspension systems,
the load sensor port (P42) must be plumbed to a fixed
axle air ride bellows. NOTE: The sensor must not be
plumbed to lift axle bellows since they are not charged
when the axle is not being used. The function of this
sensor is to monitor the pressure and send an electrical
signal directly proportional to the trailer’s axle load to
the ECU.

•

L ateral Accelerometer Sensor: The lateral
accelerometer sensor senses the lateral movement
of the trailer and sends an electrical signal directly
proportional to the trailer’s lateral acceleration to the
ECU.

•

odulator Relay Valve (MRV): MRVs are integrated
M
into the module and are controlled electrically by the
ECU to decrease, hold, or allow the fully applied brake
pressure into the brake chamber to control the braking
torque at the wheels.
Supply Pressure Sensor: Supply pressure sensors
are non-serviceable, and are located within the module.

TRSP Intervention with Driver Actions
It is possible that the driver will also apply the brakes before
or during a TRSP intervention by the TABS‑6 Advanced
MC module. In all cases, the Electronic Control Unit (ECU)
monitors the driver’s brake application and compares that
to the amount of braking the TRSP program has calculated
needs to be applied. The pressure delivered to the brakes
will always be the higher of the two (2) values.

5. COMPONENTS
Installations of the TABS‑6 Advanced MC module use the
following components:
Internal
• ECU: The ECU monitors the WSS signals, lateral
accelerometer sensor signal, and various pressure
sensors (and, if configured, external spring deflection
sensor) to determine when the Antilock Braking System
(ABS) and/or TRSP intervention is required. When
needed, the ECU actuates the appropriate pressure
Modulator Relay Valves (MRVs) to optimize the brake
pressure. The ECU monitors the system to detect
and warn the driver of any malfunctions. Diagnostic
Trouble Codes (DTCs) are stored in the ECU and can
be reviewed to diagnose the TABS‑6 Advanced MC
module system.

•

External
• E xternal Load Sensor: For spring suspension
systems, an external electrical spring deflection sensor
is installed – typically as close to the center (±5 in. /
12.7 cm) as possible of an axle with linkage attached
to the center of the axle (but MUST NOT be installed
on a lift axle), See Figure 3. Vehicles with a mechanical
load sensor have the port (P42) used for sensing the
air suspension system plugged.
•

oad Sensor: See Figure 3. If a trailer is equipped with
L
an external electrical spring deflection sensor, a linkage
is attached to an axle (but must not be installed on a lift
axle) – within five (5) in. (12.7 cm) of the center of the
axle – connects to a load sensor attached to the chassis
of the vehicle. The output from the sensor is an electrical
signal that is proportional to the spring deflection. The
connection to the ECU is via the auxiliary 12-pin or 2.4
connector.

5

•

Lift Axle Sensing: If a trailer is equipped with a lift axle,
then lift axle sensing must be used, unless configured
for automatic lift axle control (see below). A pressure
threshold switch must be installed in the lift bag for the
lift axle and connected to the Electronic Control Unit
(ECU). The ECU can then monitor the position of the lift
axle and will compensate correctly for the load transfer
to the other axle(s) when the lift axle is raised.
Mounting
Bolts

Rubber Link
and Rod

Load Sensor
FRONT OF TRAILER

Figure 4 – Trailer-Mounted ABS Indicator Lamp
•

Wheel Speed Sensors (WSS): Located at selected
hubs, WSS detect the rotation of individual wheels
and send an electrical signal to the ECU proportional
to the rotational velocity. See Figure 5.

•

Pigtail Wiring Harness: A power pigtail harness is
required. Auxiliary harnesses are available, as needed.
See Figure 6.