WABCO Easy-Stop Basic User manual

EASY-STOP™TRAILER
ABS: 2S/1M (BASIC AND
STANDARD), 2S/2M, 4S/2M
AND 4S/3M SYSTEMS
MAINTENANCE MANUAL

Copyright 7-18 WABCO
Service Notes
Important Information
This manual contains maintenance procedures for WABCO's Easy-StopTM Trailer Anti-Lock Braking System
(ABS). The information contained in this manual was current at time of publication and is subject to change
without notice or liability.
You must follow company procedures and understand all procedures and instructions before you begin to
service or repair a unit. Some procedures require the use of special tools for safe and correct service.
Failure to use special tools when required can cause serious personal injury to service personnel, as well as
damage equipment and components.
WABCO uses the following notations to warn the user of possible safety issues and to provide information
that will prevent damage to equipment and components.
WARNING
A WARNING indicates that you must follow
a procedure exactly. Otherwise, serious
personal injury can occur.
CAUTION
A CAUTION indicates that you must follow
a procedure exactly. Otherwise, damage to
equipment or components can occur. Serious
personal injury can also result, in addition to
damaged or malfunctioning equipment
or components.
NOTE
A NOTE indicates an operation, procedure or
instruction that is important for proper service.
A NOTE can also supply information that can
help to make service quicker and easier.
TORQUE
This symbol indicates that you must tighten
fasteners to a specific torque value.
Also Available from WABCO
ABS Tips
앫Driver Tips (SP-93161)
앫How to Brake with ABS audio cassette
(SP-94126)
앫Driver Tips for Trailer ABS Warning Lamps
(TP-97132)

Table of Contents
i
Asbestos and Non-Asbestos Fiber Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Section 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Section 2: System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Section 3: ABS Questions and Answers
The Electronic Control Unit (ECU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
The ABS Warning Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Types of Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Section 4: System Configurations
2S/1M Trailer ABS Configuration Installation Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2S/2M Trailer ABS Configuration Installation Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4S/2M Trailer ABS Configuration Installation Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
4S/3M Trailer ABS Configuration Installation Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Power Cable Wiring Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Section 5: Diagnostics
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Blink Code Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Diagnostic Tools For ECUs with External Diagnostic Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Normal Mode Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Repair Existing Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Section 6: Component Replacement
Wheel Speed Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
ABS Relay Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
The ECU/Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
How to Install the Blink Code Diagnostic Tool into the SAE J1587 Diagnostic Connector . . . . . . . .30
Section 7: Sensor Adjustment & Component Testing
How to Test Wheel Speed Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Sensor Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Sensor Output Voltage Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Check ABS Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
ABS External Modulator Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Final Test Before Returning a Trailer to Service:
For ECU/Valve Assembly Part Number 472 500 011 0
(without external diagnostic connector) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
For ECU/Valve Assembly Part Numbers 472 500 012 0 and
S 472 500 013 0 (Units with External Diagnostic Connector) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Trailer Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Section 8: Appendixes
Appendix A: Expert Mode Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Appendix B: Reconfigure Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Appendix C: Warning Lamp Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

ii
ASBESTOS FIBER WARNING
The following procedures for servicing brakes are recommended to reduce
exposure to asbestos fiber dust, a cancer and lung disease hazard. Material
Safety Data Sheets are available from WABCO.
Hazard Summary
Because some brake linings contain asbestos, workers who service brakes must understand
the potential hazards of asbestos and precautions for reducing risks. Exposure to airborne
asbestos dust can cause serious and possibly fatal diseases, including asbestosis (a chronic
lung disease) and cancer, principally lung cancer and mesothelioma (a cancer of the lining of
the chest or abdominal cavities). Some studies show that the risk of lung cancer among
persons who smoke and who are exposed to asbestos is much greater than the risk for
non-smokers. Symptoms of these diseases may not become apparent for 15, 20 or more years
after the first exposure to asbestos.
Accordingly, workers must use caution to avoid creating and breathing dust when servicing
brakes. Specific recommended work practices for reducing exposure to asbestos dust
follow. Consult your employer for more details.
Recommended Work Practices
1. Separate Work Areas. Whenever feasible, service brakes in a separate area away
from other operations to reduce risks to unprotected persons. OSHA has set a
maximum allowable level of exposure for asbestos of 0.1 f/cc as an 8-hour
time-weighted average and 1.0 f/cc averaged over a 30-minute period. Scientists
disagree, however, to what extent adherence to the maximum allowable exposure
levels will eliminate the risk of disease that can result from inhaling asbestos dust.
OSHA requires that the following sign be posted at the entrance to areas where
exposures exceed either of the maximum allowable levels:
DANGER: ASBESTOS
CANCER AND LUNG DISEASE HAZARD
AUTHORIZED PERSONNEL ONLY
RESPIRATORS AND PROTECTIVE CLOTHING
ARE REQUIRED IN THIS AREA
2. Respiratory Protection. Wear a respirator equipped with a high-efficiency (HEPA)
filter approved by NIOSH or MSHA for use with asbestos at all times when servicing
brakes, beginning with the removal of the wheels.
3. Procedures for Servicing Brakes.
a. Enclose the brake assembly within a negative pressure enclosure. The
enclosure should be equipped with a HEPA vacuum and worker arm sleeves.
With the enclosure in place, use the HEPA vacuum to loosen and vacuum
residue from the brake parts.
b. As an alternative procedure, use a catch basin with water and a biodegradable,
non-phosphate, water-based detergent to wash the brake drum or rotor and
other brake parts. The solution should be applied with low pressure to prevent
dust from becoming airborne. Allow the solution to flow between the brake
drum and the brake support or the brake rotor and caliper. The wheel hub and
brake assembly components should be thoroughly wetted to suppress dust
before the brake shoes or brake pads are removed. Wipe the brake parts clean
with a cloth.
c. If an enclosed vacuum system or brake washing equipment is not available,
employers may adopt their own written procedures for servicing brakes,
provided that the exposure levels associated with the employer's procedures
do not exceed the levels associated with the enclosed vacuum system or brake
washing equipment. Consult OSHA regulations for more details.
d. Wear a respirator equipped with a HEPA filter approved by NIOSH or MSHA for
use with asbestos when grinding or machining brake linings. In addition, do
such work in an area with a local exhaust ventilation system equipped with a
HEPA filter.
e. NEVER use compressed air by itself, dry brushing, or a vacuum not equipped
with a HEPA filter when cleaning brake parts or assemblies. NEVER use
carcinogenic solvents, flammable solvents, or solvents that can damage brake
components as wetting agents.
4. Cleaning Work Areas. Clean work areas with a vacuum equipped with a HEPA filter
or by wet wiping. NEVER use compressed air or dry sweeping to clean work areas.
When you empty vacuum cleaners and handle used rags, wear a respirator equipped
with a HEPA filter approved by NIOSH or MSHA for use with asbestos. When you
replace a HEPA filter, wet the filter with a fine mist of water and dispose of the used
filter with care.
5. Worker Clean-Up. After servicing brakes, wash your hands before you eat, drink or
smoke. Shower after work. Do not wear work clothes home. Use a vacuum equipped
with a HEPA filter to vacuum work clothes after they are worn. Launder them
separately. Do not shake or use compressed air to remove dust from work clothes.
6. Waste Disposal. Dispose of discarded linings, used rags, cloths and HEPA filters
with care, such as in sealed plastic bags. Consult applicable EPA, state and local
regulations on waste disposal.
Regulatory Guidance
References to OSHA, NIOSH, MSHA, and EPA, which are regulatory agencies in the United
States, are made to provide further guidance to employers and workers employed within the
United States. Employers and workers employed outside of the United States should consult
the regulations that apply to them for further guidance.
NON-ASBESTOS FIBER WARNING
The following procedures for servicing brakes are recommended to reduce
exposure to non-asbestos fiber dust, a cancer and lung disease hazard. Material
Safety Data Sheets are available from WABCO.
Hazard Summary
Most recently manufactured brake linings do not contain asbestos fibers. These brake linings
may contain one or more of a variety of ingredients, including glass fibers, mineral wool,
aramid fibers, ceramic fibers and silica that can present health risks if inhaled. Scientists
disagree on the extent of the risks from exposure to these substances. Nonetheless,
exposure to silica dust can cause silicosis, a non-cancerous lung disease. Silicosis gradually
reduces lung capacity and efficiency and can result in serious breathing difficulty. Some
medical experts believe other types of non-asbestos fibers, when inhaled, can cause similar
diseases of the lung. In addition, silica dust and ceramic fiber dust are known to the State of
California to cause lung cancer. U.S. and international agencies have also determined that
dust from mineral wool, ceramic fibers and silica are potential causes of cancer.
Accordingly, workers must use caution to avoid creating and breathing dust when servicing
brakes. Specific recommended work practices for reducing exposure to non-asbestos dust
follow. Consult your employer for more details.
Recommended Work Practices
1. Separate Work Areas. Whenever feasible, service brakes in a separate area away
from other operations to reduce risks to unprotected persons.
2. Respiratory Protection. OSHA has set a maximum allowable level of exposure for
silica of 0.1 mg/m3as an 8-hour time-weighted average. Some manufacturers of non-
asbestos brake linings recommend that exposures to other ingredients found in non-
asbestos brake linings be kept below 1.0 f/cc as an 8-hour time-weighted average.
Scientists disagree, however, to what extent adherence to these maximum allowable
exposure levels will eliminate the risk of disease that can result from inhaling non-
asbestos dust.
Therefore, wear respiratory protection at all times during brake servicing, beginning
with the removal of the wheels. Wear a respirator equipped with a high-efficiency
(HEPA) filter approved by NIOSH or MSHA, if the exposure levels may exceed OSHA or
manufacturers' recommended maximum levels. Even when exposures are expected to
be within the maximum allowable levels, wearing such a respirator at all times during
brake servicing will help minimize exposure.
3. Procedures for Servicing Brakes.
a. Enclose the brake assembly within a negative pressure enclosure. The
enclosure should be equipped with a HEPA vacuum and worker arm sleeves.
With the enclosure in place, use the HEPA vacuum to loosen and vacuum
residue from the brake parts.
b. As an alternative procedure, use a catch basin with water and a biodegradable,
non-phosphate, water-based detergent to wash the brake drum or rotor and
other brake parts. The solution should be applied with low pressure to prevent
dust from becoming airborne. Allow the solution to flow between the brake
drum and the brake support or the brake rotor and caliper. The wheel hub and
brake assembly components should be thoroughly wetted to suppress dust
before the brake shoes or brake pads are removed. Wipe the brake parts clean
with a cloth.
c. If an enclosed vacuum system or brake washing equipment is not available,
carefully clean the brake parts in the open air. Wet the parts with a solution
applied with a pump-spray bottle that creates a fine mist. Use a solution
containing water, and, if available, a biodegradable, non-phosphate,
water-based detergent. The wheel hub and brake assembly components should
be thoroughly wetted to suppress dust before the brake shoes or brake pads
are removed. Wipe the brake parts clean with a cloth.
d. Wear a respirator equipped with a HEPA filter approved by NIOSH or MSHA
when grinding or machining brake linings. In addition, do such work in an area
with a local exhaust ventilation system equipped with a HEPA filter.
e. NEVER use compressed air by itself, dry brushing, or a vacuum not equipped
with a HEPA filter when cleaning brake parts or assemblies. NEVER use
carcinogenic solvents, flammable solvents, or solvents that can damage brake
components as wetting agents.
4. Cleaning Work Areas. Clean work areas with a vacuum equipped with a HEPA filter or
by wet wiping. NEVER use compressed air or dry sweeping to clean work areas. When
you empty vacuum cleaners and handle used rags, wear a respirator equipped with a
HEPA filter approved by NIOSH or MSHA, if the exposure levels may exceed OSHA or
manufacturers' recommended maximum levels. When you replace a HEPA filter, wet
the filter with a fine mist of water and dispose of the used filter
with care.
5. Worker Clean-Up. After servicing brakes, wash your hands before you eat, drink or
smoke. Shower after work. Do not wear work clothes home. Use a vacuum equipped
with a HEPA filter to vacuum work clothes after they are worn. Launder them
separately. Do not shake or use compressed air to remove dust from work clothes.
6. Waste Disposal. Dispose of discarded linings, used rags, cloths and HEPA filters with
care, such as in sealed plastic bags. Consult applicable EPA, state and local
regulations on waste disposal.
Regulatory Guidance
References to OSHA, NIOSH, MSHA, and EPA, which are regulatory agencies in the United
States, are made to provide further guidance to employers and workers employed within the
United States. Employers and workers employed outside of the United States should consult
the regulations that apply to them for further guidance.

Page 1
Section 1
Introduction
Section 1Introduction
Overview
This manual describes how WABCO's Easy-Stop™
Trailer Anti-Lock Braking System (ABS) works;
answers some basic ABS questions; outlines
procedures on how to adjust, test, remove and
install ABS components, as well as how to test for
faults in the system by using Blink Code
Diagnostics; and illustrates ABS components and
wiring and plumbing installation diagrams. This
manual does not contain Original Equipment
Manufacturer (OEM) installation instructions. New
installations require the following documentation:
앫Easy-Stop™ Basic (2S/1M without external
diagnostics): TP-97145
앫Easy-Stop™ Standard (2S/1M, 2S/2M, 4S/2M
with external diagnostics): TP-97147
앫Easy-Stop™ Standard (4S/3M with external
diagnostics): TP-97153
Scope of Blink Code
Diagnostics in This Manual
This manual contains blink code diagnostics
information and instructions for most of
the ECU/Valve Assemblies listed in Ta b l e A —
Scope of Blink Code Diagnostics.
The serial and part numbers are located on the
ECU/Valve Assembly. Refer to Figure 1.1.
Table A — Scope of Blink Code Diagnostics
ECU/Valve Assembly Part
Number
Blink Code
Diagnostics
472 500 001 0
(Serial Number 3080002745
and lower)
Contact WABCO for
blink code
diagnostics
information.
472 500 001 0
(Serial Number 3080002746
and higher)
See Section 5 and
Appendix A and B.
472 500 011 0
(Serial Number Not
Applicable)
See Section 5 and
Appendix C.
472 500 012 0
(Serial Number Not
Applicable)
See Section 5 and
Appendix A, B
and C.
472 500 013 0
(Serial Number Not
Applicable)
See Section 5 and
Appendix A, B
and C.
Figure 1.1
1003290d
SERIAL NUMBER
EASY-STOP™ TRAILER ABS ECU/VALVE ASSEMBLY
DATE CODE
FIRST TWO DIGITS = BUILD WEEK
LAST TWO DIGITS = BUILD YEAR
PART NUMBER

Section 1
Introduction
Page 2
Easy-Stop™ Trailer ABS Parts
Parts book PB-96133 lists WABCO Easy-Stop™
replacement parts. To obtain a copy, contact
WABCO North America Customer Care at
855-228-3203.
What Is WABCO’s Easy-Stop™
Trailer ABS?
WABCO’s Easy-Stop™ Trailer ABS is an electronic,
self-monitoring system that works
with standard air brakes. The major components
of the system are the Electronic Control Unit
(ECU)/Valve Assembly, ABS relay (modulator)
valve, tooth wheel and wheel speed sensor.
Refer to Figure 1.2.
ECU Part Numbers 472 500 001 0, 472 500 012 0
and 472 500 013 0 have an external diagnostics
connector for use with a special diagnostic tool.
These models are also compatible with an MPSI
Pro-Link®9000 diagnostic tool and WABCO
cartridge. ECU/Valve Assembly 472 500 011 0 does
not have a diagnostic connector port. Diagnostic
procedures for all of these ECUs are detailed in
Section 5, "Diagnostics" of this manual.
The ABS configuration defines the number of
wheel speed sensors and ABS relay valves used in
a system. For example, a 2S/1M configuration
includes two wheel sensors and one ABS relay
valve. A 2S/2M configuration includes two wheel
sensors and two relay valves. A 4S/2M
configuration includes four wheel sensors and
two ABS relay valves.
How Trailer ABS Works
WABCO ABS is an electronic system that monitors
and controls wheel speed during braking. The
system works with standard air
brake systems.
ABS monitors wheel speeds at all times and
controls braking during wheel lock situations. The
system improves vehicle stability and control by
reducing wheel lock during braking.
The ECU receives and processes signals from the
wheel speed sensors. When the ECU detects a
wheel lockup, the unit activates the appropriate
modulator valve, and air pressure is controlled.
In the event of a malfunction in the system, the
ABS in the affected wheel(s) is disabled; that wheel
still has normal brakes. The other wheels keep the
ABS function.
An ABS warning lamp lets drivers know the status
of the system.
Figure 1.2
1 ECU/Valve Assembly
2 External ABS Relay Valve (not used in
1M configurations)
3 Tooth Wheel
4 Wheel Speed Sensor
1002071d
2
1
4
3

Page 3
Section 2
System Components
Section 2SystemComponents
ECU/Valve Assembly
앫12 volt
앫Integrated ECU and ABS relay valve
앫The 2S/1M Basic ECU/Valve Assembly does not
have an external diagnostics connector.
ABS External Valve
앫Controls air pressure to the brake chambers
where it is plumbed.
앫During ABS operation, the valve adjusts air
pressure to the brake chambers to control
braking and prevent wheel lock.
앫Used in conjunction with ECU/Valve Assembly
for 2M or 3M systems.
Sensor with Molded Socket
앫Measures the speed of a tooth wheel rotating
with the vehicle wheel.
앫Produces an output voltage proportional to
wheel speed.
Sensor Spring Clip
앫Holds the wheel speed sensor in close proximity
to the tooth wheel.
Sensor Extension Cable
앫Two-wire cable with molded-on connector.
앫Connects the wheel speed sensor to the ECU.
Figure 2.1
1 2S/1M Basic
2 Standard
Figure 2.2
1002072d
2S/1M BASIC STANDARD
1002073c
Figure 2.3
Figure 2.4
Figure 2.5
1002074a
1002075a
1002076a

Section 2
System Components
Page 4
Connection Cable for ABS External Valves
앫Three-wire cable with connector.
앫Connects the ABS external valve to the ECU.
앫“Y” cable for use with 4S/3M configurations
also available.
Power Cables
앫Connects power to the ECU and provides a
connection for the warning lamp.
앫Available with blunt-end four- or five-wire cable
or four- or five-wire industry standard harness
connector at one end.
앫Molded connector on opposite end used to
attach cable to ECU.
Diagnostic Cable
앫Provides for blink code diagnostics and
diagnostics using the MPSI Pro-Link®9000
diagnostic tool.
앫Five-wire cable with over-molded connector to
ECU on one end and SAE J1587 diagnostic
connector over-molded on the other end.
Diagnostic Tool
앫Sealed switch and lamp that connects to the
SAE J1587 diagnostic connector.
앫Used to activate blink code diagnostics,
reconfigure the ECU and test the
ECU installation.
앫Protective dust cap included.
앫Designed to remain on the trailer at all times.
Figure 2.6
Figure 2.7
1 Blunt End
2 Industry Standard
1002077a
1002078b
BLUNT END
INDUSTRY
STANDARD
Figure 2.8
Figure 2.9
1002079a
1002080a

Page 5
Section 2
System Components
Diagnostic Cable Mounting Bracket
앫Bracket used to mount the diagnostic cable
assembly to the trailer.
ECU/Valve Assembly Mounting Bracket
앫Bracket used to remote mount the ECU/Valve
Assembly to the trailer frame.
Diagnostic Cable Assembly with Protective Cap
앫Diagnostic cable mounted to the bracket
with a protective cap on the SAE J1587
diagnostic connector.
Diagnostic Cable Assembly with Diagnostic Tool
앫Diagnostic cable mounted to the bracket with a
diagnostic tool connected to the SAE J1587
diagnostic connector.
앫Protective dust cap included.
Tooth Wheel
앫A machined ring mounted to the
machined surface on the hub of each
ABS-monitored wheel.
Figure 2.10
Figure 2.11
Figure 2.12
1002081a
1002082a
1002083a
Figure 2.13
Figure 2.14
1002084a
1002085a

Section 2
System Components
Page 6
Installation Hardware Kit
앫Contains Schedule 80 NPT pipe nipple fittings
and Grade 8, 3/8-inch SAE bolts for proper
mounting of ABS components to the trailer
frame or reinforced air tanks.
Easy-Stop™ Trailer ABS Warning Label
앫Provides information about the operation of the
ABS warning lamp and illustrates blink code
fault locations.
앫Label is self-adhesive and is mounted on the
trailer near the ABS warning lamp.
앫If there is no warning label on your trailer, let
your supervisor know. Labels are available from
WABCO. Ask for Part Number TP-95172.
MPSI Pro-Link®9000 Diagnostic Tool
앫Provides diagnostic and testing capability for
ABS components.
앫Requires a cartridge (version 4.0 or higher)
designed for use with WABCO ABS.
NOTE
The Pro-Link®9000 diagnostic tool is not available
from WABCO. Contact Kent-Moore at
800-328-6657 to order.
Figure 2.15
Figure 2.16
1003296a
1002094a

Page 7
Section 3
ABS Questions and Answers
Section 3A BS Quest ions and Answ ers
The Electronic Control
Unit (ECU)
How do you activate the ECU?
In a constant-powered system, the ECU activates
and then begins a self-diagnostic check of the
system when you turn the ignition ON. In a
stoplight-powered system, the ECU activates when
you apply the brakes. All trailers manufactured on
or after March 1, 1998 will be equipped with ABS
that has constant power capability with stoplight
power as back-up.
What if the ECU finds a fault in an ABS component
during normal operation?
If the ECU senses a fault in the system (with an
ABS valve, for example), the ECU turns the trailer
ABS warning lamp on and returns the wheel
controlled by that valve to standard braking. Or, if
the ECU finds a fault with one wheel speed sensor
in a system that has four sensors on a tandem
axle, the ECU uses information from the other
sensor on the same side of the tandem to ensure
continuous ABS function. The ECU continues to
provide full ABS function to the wheels unaffected
by system faults. However, the ECU will turn the
trailer ABS warning lamp on to tell the driver a
fault has been detected in the system.
How does the ECU respond to a wheel
approaching lock-up?
The ECU directs the ABS relay valve to function as
a modulator valve and adjust air pressure to the
chambers up to five times a second. This pressure
adjustment allows a wheel (or wheels) to rotate
without locking.
The ABS Warning Lamp
What is the function of the warning lamp?
The warning lamp enables a driver to monitor the
ABS at all times. Refer to the OEM operating
manual for the mounting location of the
warning lamp.
How does the warning lamp operate?
How the warning lamp operates depends on
whether the ABS is powered by stoplight or
constant power:
앫If the trailer was manufactured prior to February
28, 1998, or was manufactured outside of the
United States, the ABS may be either stoplight
or constant powered.
앫If the trailer was manufactured March 1, 1998 or
later — and was manufactured in the United
States — it will have constant power capability.
This is mandated by Federal Motor Vehicle
Safety Standard (FMVSS) 121.
Check your vehicle specification sheet to
determine the type of ABS power. Ta b l e B —
Stoplight Power and Table C — Constant Power,
in this section, illustrate warning lamp operation
on stoplight and constant powered
ABS systems.
Table B — Stoplight Power
System Power Comes from Activating the Stoplight Circuit.
Brakes Fault in System Vehicle Speed Warning Lamp
Released N.A. N.A. OFF
Applied NO Less than 4 mph ON for 3 seconds, then goes OFF.
Applied NO Greater than 4 mph Flashes once, then stays OFF for
remainder of stop.
Applied YES N.A. ON

Section 3
ABS Questions and Answers
Page 8
Table C — Constant Power
An ECU with part number 472 500 001 0
manufactured prior to September 1997 requires all
sensed wheels to detect a 4 mph signal to shut off
the ABS warning lamp. Do not confuse this with a
faulty ABS system. If the warning lamp stays on
when the brakes are applied to a moving vehicle,
service the ABS system.
Most trailers manufactured prior to February 1998
require that the brakes be applied to operate the
ABS warning lamp. If the warning lamp stays on
when the brakes are applied to a moving vehicle,
service the ABS system.
What does the trailer ABS warning lamp mean to
service personnel?
The trailer ABS warning lamp indicates the status
of the trailer ABS. If it comes ON and stays ON
when you apply the brakes to a moving vehicle,
there is an ABS malfunction. It is normal for the
lamp to come ON and go OFF to perform a bulb
check, but it should not stay ON when the vehicle
is moving above 4 mph. As with any safety system,
it is important not to ignore this warning. If the
warning lamp indicates a malfunction, the vehicle
can be operated to complete the trip, but it is
important to have it serviced as soon as possible
using the appropriate maintenance manual to
ensure proper braking performance and that the
benefits of ABS remain available to your drivers.
Typical ABS warning lamp mounting locations are
illustrated in Figure 3.1.
For more information, contact WABCO North
America Customer Care at 855-228-3203.
System Is Powered When Ignition Is Switched ON.
Brakes Ignition Fault in System Vehicle Speed Warning Lamps (Trailer and Dash)
Released OFF N.A. N.A. OFF
Released ON NO Less than 4 mph ON for 3 seconds, then go OFF.
Released ON NO Greater than 4 mph OFF
Released ON YES N.A. ON
Applied OFF NO Less than 4 mph ON for 3 seconds, then go OFF.
Applied OFF NO Greater than 4 mph Flash once, then stay OFF for
remainder of stop.
Applied OFF YES N.A. ON
Applied ON NO Less than 4 mph ON for 3 seconds, then go OFF.
Applied ON NO Greater than 4 mph OFF
Applied ON YES N.A. ON
Figure 3.1
1 Prior to March 1, 1998
2 On or after March 1, 1998
Typical ABS Warning Lamp Mounting Locations

Page 9
Section 3
ABS Questions and Answers
Can you continue to operate a vehicle when the
warning lamp indicates a fault?
Yes. When a fault exists in the ABS, standard
braking returns to the affected wheel, and the ABS
still controls other monitored wheels. This lets you
complete the trip. You should not ignore the
warning lamp and should have the vehicle
serviced as soon as possible after the lamp
comes ON and stays ON.
Types of Faults
What is a “fault” in the system?
A fault in the system is a problem that can exist in
the ABS or in the system’s components. Faults
can be either existing faults or intermittent
stored faults.
What is an existing fault?
An existing fault is a problem that exists currently
in the system. For example, a damaged sensor
cable is an existing fault that the ECU will detect
and store into memory until you identify the cause,
repair the cable and clear the fault from the ECU.
What is an intermittent fault?
An intermittent fault is a problem that usually
occurs only under certain driving conditions. For
example, the ECU may detect a loose cable or wire
or receive an erratic signal from a wheel sensor.
Since intermittent faults can be unpredictable and
may only happen periodically, you can use
information stored in ECU memory to find and
correct the loose cable or wire.
Is an intermittent fault difficult to locate
and repair?
It can be, because you may not be able to easily
see the cause of the problem. WABCO
recommends that you write down intermittent
faults to help you isolate a fault that recurs over a
period of time.
Can the ECU store more than one fault
in memory?
Yes. And the ECU retains existing and intermittent
faults in memory even when you turn OFF the
power to the ECU.
NOTE
For part number information, refer to PB-96133.
Copies are available from the WABCO North
America Customer Care at 855-228-3203.

Notes
Page 10

Page 11
Section 4
System Configurations
Section 4System Configur ations
2S/1M Trailer ABS Configuration Without External Diagnostics
Capability Installation Diagram
For direct tank-mounted installations, see “How to
Install the ECU/Valve Assembly,” in Section 6,
"Component Replacement".
Typical Application:
앫Single-Axle Dolly
앫Single- and Tandem-Axle Semi-Trailer
NOTE
Sensors may be installed on either axle,
depending upon suspension and other
vehicle characteristics.
Figure 4.1
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
1 ECU/Valve Assembly (YE)
2 Air Tanks
1003292e
AIR TANK
ECU/VALVE
ASSEMBLY (YE)
YE1
YE2
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
AIR TANK

Section 4
System Configurations
Page 12
2S/1M Trailer ABS Configuration with External Diagnostics
Capability Installation Diagram
For direct tank-mounted installations, see “How to
Install the ECU/Valve Assembly” in Section 6,
"Component Replacement".
Typical Application:
앫Single-Axle Dolly
앫Single- and Tandem-Axle Semi-Trailer
NOTE
Sensors may be installed on either axle,
depending upon suspension and other
vehicle characteristics.
Figure 4.2
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
1 ECU/Valve Assembly (YE)
2 Air Tanks
1002086f
AIR TANK
ECU/VALVE
ASSEMBLY (YE)
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
AIR TANK
YE1
YE2

Page 13
Section 4
System Configurations
2S/2M Trailer ABS Configuration Installation Diagram
For direct tank-mounted installations, see “How to
Install the ECU/Valve Assembly” in Section 6,
"Component Replacement".
Typical Application:
앫Single- and Tandem-Axle Semi-Trailer
NOTE
Sensors may be installed on either axle,
depending upon suspension and other
vehicle characteristics.
Figure 4.3
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
1 ECU/Valve Assembly (YE)
2 Air Tanks
3 External Valve (BU)
1002087e
BU1
AIR TANK
ECU/VALVE
ASSEMBLY (YE)
AIR TANK
YE1
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
EXTERNAL
VALVE (BU)

Section 4
System Configurations
Page 14
4S/2M Trailer ABS Configuration Installation Diagram
For direct tank-mounted installations, see “How to
Install the ECU/Valve Assembly” in Section 6,
"Component Replacement".
Typical Application:
앫Tandem and Tri-Axle Semi-Trailer
Figure 4.4
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
1 ECU/Valve Assembly (YE)
2 Air Tanks
3 External Valve (BU)
1002088e
YE1 YE2
EXTERNAL
VALVE (BU)
AIR TANK
BU1 BU2
AIR TANK
ECU/VALVE
ASSEMBLY (YE)
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines

Page 15
Section 4
System Configurations
4S/2M Trailer ABS Configuration Diagram for Lift Axle Applications
(Forward Lift Axle Installation Diagram)
For direct tank-mounted installations, see “How to
Install the ECU/Valve Assembly” in Section 6,
"Component Replacement".
Typical Application:
앫Tandem and Tri-Axle Semi-Trailer
Figure 4.5
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
1 ECU/Valve Assembly (YE)
2 External Valve (BU)
3 Air Tanks
4 Lift Axle
5 Fixed Axle
1002089e
EXTERNAL
VALVE (BU)
AIR TANK
ECU/VALVE
ASSEMBLY (YE)
AIR TANK
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
BU2 BU1
YE2 YE1
LIFT AXLE FIXED AXLE
LIFT AXLE FIXED AXLE

Section 4
System Configurations
Page 16
4S/2M Trailer ABS Configuration Diagram for Lift Axle Applications
(Rear Lift Axle Installation Diagram)
For direct tank-mounted installations, see “How to
Install the ECU/Valve Assembly” in Section 6,
"Component Replacement".
Typical Application:
앫Tandem and Tri-Axle Semi-Trailer
Figure 4.6
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines
1 ECU/Valve Assembly (YE)
2 External Valve (BU)
3 Air Tanks
4 Fixed Axle
5 Lift Axle
1002090e
EXTERNAL
VALVE (BU)
AIR TANK
ECU/VALVE
ASSEMBLY (YE)
AIR TANK
FIXED AXLE LIFT AXLE
FIXED AXLE LIFT AXLE
BU1 BU2
YE1 YE2
A Service/Control Lines
B Sensor Cables
C Service to Brake Lines (Delivery Lines)
D Air Supply/Emergency Lines