WABCO SMARTTRAC MM1543 User manual

SMARTTRAC™
HYDRAULIC ANTI-LOCK
BRAKING SYSTEMS
MAINTENANCE MANUAL
MM1543

3
Table of Contents
Table of Contents
1 General Information. ...................................................................................................................................................5
1.1 Symbols Used in this Document ........................................................................................................................5
1.2 How to Obtain Additional Maintenance, Service and Product Information.........................................................6
1.3 How to Obtain Parts and Kits.............................................................................................................................6
1.4 WABCO TOOLBOX PLUS™ Software ..............................................................................................................6
1.5 WABCO Academy..............................................................................................................................................6
1.6 WABCO Online Product Catalog .......................................................................................................................6
1.7 Your Direct Contact to ZF CVS ..........................................................................................................................7
2 Safety Information.......................................................................................................................................................8
2.1 Provisions for a safe work environment .............................................................................................................8
3 Introduction. ................................................................................................................................................................9
3.1 About This Manual .............................................................................................................................................9
3.2 Manual Information ............................................................................................................................................9
3.3 Overview ............................................................................................................................................................9
3.4 System Components........................................................................................................................................12
4 Troubleshooting and Testing. ..................................................................................................................................17
4.1 Maintenance ....................................................................................................................................................17
4.2 Wiring Diagrams ..............................................................................................................................................18
4.3 System Diagnostics .........................................................................................................................................20
4.4 Testing the System...........................................................................................................................................22
4.5 Testing with TOOLBOX™ Software .................................................................................................................22
4.6 Standard Testing ..............................................................................................................................................23
4.7 Component Testing ..........................................................................................................................................23
4.8 Voltage Check..................................................................................................................................................24
4.9 ESC Testing .....................................................................................................................................................26
4.10 Steering Angle Sensor (SAS) Testing ..............................................................................................................29
4.11 ECU Circuit Testing..........................................................................................................................................31
4.12 J1939 Serial Communications Testing.............................................................................................................31

Edition 1
Version 2 (03.2022)
MM1543 (en)
This publication is not subject to any update service. Information contained in this
publication was in e󰀨ect at the time the publication was approved for printing and is
subject to change without notice or liability. ZF CV Systems North America LLC reserves
the right to revise the information presented or to discontinue the production of parts
described at any time.
You will nd the current edition at: https://zf.com/cvliterature
5 Component Replacement.........................................................................................................................................32
5.1 Component Removal and Installation ..............................................................................................................32
5.2 Brake Bleeding Procedures .............................................................................................................................36
6 Appendix I..................................................................................................................................................................52
6.1 SPN/FMI Codes ...............................................................................................................................................52
7 Appendix II.................................................................................................................................................................63
7.1 Aftermarket Programming................................................................................................................................63
7.2 Minimum Requirements for Aftermarket Programming....................................................................................63
7.3 Aftermarket Programming Procedures ............................................................................................................64

1 General Information
1.1 Symbols Used in this Document
DANGER
Description of an immediate situation which will result in irreversible injury or death if the warning is
ignored.
WARNING
Description of a possible situation which may result in irreversible injury or death if the warning is
ignored.
CAUTION
Description of a possible situation which may result in irreversible injury if the warning is ignored.
NOTICE
Description of a possible situation which may result in material damage if the warning is ignored.
Important information, notices and/or tips
Reference to information on the Internet
Descriptive text
– Action step
1. Action step 1 (in ascending order)
2. Action step 2 (in ascending order)
ÖResult of an action
• Listing
Indicating the use of a tool / WABCO tool
5
General Information

6
General Information
1.2 How to Obtain Additional Maintenance, Service and Product
Information
If you have any questions about the material covered in this publication, or for more
information about the WABCO product line, please contact WABCO Customer Care
Center at 855-228-3203, by email at [email protected], or visit our website:
www.zf.com/cv.
Refer to the Society of Automotive Engineers (SAE) website to nd all current SAE
documents and standards applicable to WABCO products (such as SAE J447 and SAE
J908 at www.sae.org).
Refer to the National Highway Tra󰀩c Safety Administration (NHTSA) website to nd all
current documents referenced in the manual at www.nhtsa.gov.
1.3 How to Obtain Parts and Kits
Contact the WABCO Customer Care Center at 855-228-3203 (United States and Canada);
800-953-0248 (Mexico). Email: [email protected].
1.4 WABCO TOOLBOX PLUS™ Software
TOOLBOX PLUS™ Software provides PC diagnostic for WABCO products and can be
purchased and downloaded from https://wabco.snapon.com.
The software User Guide, MM19047 can be obtained by visiting our Literature Center.
Purchase and Download TOOLBOX PLUS™
https://wabco.snapon.com
ZF Commercial Vehicle Literature Center
https://zf.com/cvliterature
1.5 WABCO Academy
www.wabco-academy.com
1.6 WABCO Online Product Catalog
www.wabco-customercenter.com

7
General Information
1.7 Your Direct Contact to ZF CVS
ZF CV Systems North America LLC
1220 Pacic Drive
Auburn Hills, MI 48326
Customer Care Center: [phone]
www.zf.com/cv
[email protected]

8
Safety Information
2 Safety Information
2.1 Provisions for a safe work environment
Only experienced, trained and qualied automotive technicians may carry out work on the vehicle.
Read this publication carefully.
Follow all warnings, notices and instructions to avoid personal injury and property damage.
Always abide by the vehicle’s Original Equipment Manufacturer (OEM) specications and instructions.
Observe all accident regulations of the repair facility as well as regional and national regulations.
The workplace should be dry, su󰀩ciently lit and ventilated.
Use personal protective equipment if required (safety shoes, protective goggles, respiratory protection
and ear protectors).
Read and observe all Danger, Warning and Caution hazard alert messages in this publication. They provide
information that can help prevent serious personal injury, damage to components, or both.
WARNING
To prevent serious eye injury, always wear safe eye protection when you perform vehicle
maintenance or service.
WARNING
Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving. Support
the vehicle with safety stands. Do not work under a vehicle supported only by jacks. Jacks can slip
or fall over. Serious personal injury and damage to components can result.
WARNING
This product can expose you to chemicals including Nickel, which is known to the State of California
to cause cancer and birth defects or other reproductive harm. For more information, go to
www.P65Warnings.ca.gov.

9
Introduction
3 Introduction
3.1 About This Manual
This manual provides service and repair procedures for WABCO’s SmartTrac™ hydraulic anti-lock braking
system for medium-duty trucks, buses and motor home chassis.
3.2 Manual Information
This manual contains service information for the WABCO SmartTrac™ hydraulic ABS. For earlier versions
of WABCO hydraulic ABS, refer to:
MM38 C Version HABS
MM39 D Version HABS
MM0677 E Version HABS
MM0401 HPB Hydraulic Power Brake
MM1543 SmartTrac™ HABS
Copies of these manuals are posted on our website: https://zf.com/cvliterature.
3.3 Overview
WABCO SmartTrac™ Hydraulic Anti-lock Braking System (HABS) is an electronic wheel speed monitoring
and control system used on medium-duty trucks, buses and motor home chassis equipped with a hydraulic
brake system. Features included with SmartTrac™ are:
Anti-Lock Braking System (ABS)
Drag Torque Control (DTC)
Electronic Brake Force Distribution (EBD)
Hill Start Aid (HSA)
Automatic Traction Control (ATC)
Electronic Stability Control (ESC)
Typically, the hydraulic ABS unit is mounted on the frame rail of the vehicle.
4011782a

10
Introduction
3.3.1 How ABS Works
The ABS uses wheel speed sensors to measure wheel speeds. The sensors generate signals that are
transmitted to an ECU. If the wheels start to lock, the ECU signals the modulator assembly to regulate the
brake pressure of each locking wheel.
During an ABS stop, a solenoid valve in the modulator assembly is rapidly pulsed; that is, it opens and
closes several times per second to control the brake pressure. When this occurs, drivers may notice a
pulsation of the brake pedal.
An ABS warning lamp on the vehicle instrument panel alerts the driver to a possible system fault. If the ABS
warning lamp comes on during normal vehicle operation, drivers may complete their trip, but are instructed
to have their vehicle serviced as soon as possible.
In the unlikely event of an ABS malfunction, the ABS in the a󰀨ected wheel will be disabled and will return to
normal braking. The other sensed wheels may retain their ABS function. Do not rely on the ABS functioning
for any of the sensed wheels. Have the vehicle serviced as soon as possible.
3.3.2 How ATC Works
ATC uses the same wheel sensors mentioned in the above ABS description, ATC monitors drive axle wheel
speeds to detect wheel spin that can occur on slippery surfaces. ATC works automatically in three di󰀨erent
ways:
a. If a drive wheel starts to spin, ATC pulses hydraulic pressure to reduce the wheel spin. This
transfers engine torque to the wheels with better traction.
b. If all drive wheels spin, ATC reduces engine torque to provide improved traction.
c. When needed, the SmartTrac™ system will combine hydraulic pressure pulses and engine torque
reduction simultaneously.
ATC turns itself on and o󰀨; drivers do not have to select this feature. If drive wheels spin during
acceleration, the ATC indicator lamp comes on, indicating ATC is active. It goes out when the drive wheels
stop spinning.
3.3.3 How DTC Works
DTC prevents the driven wheels from locking on slippery surfaces under a condition that would result
from an engine braking event. This condition can happen if the driver releases the accelerator abruptly
or shifts down a gear quickly. The braking e󰀨ect of the engine may cause the driven wheels to slip and
they temporarily lose traction resulting in the vehicle becoming unstable. In this situation, DTC maintains
directional stability by slightly increasing engine speed until the driven wheels match the road speed again.
3.3.4 How EBD Works
EBD provides constant review of the vehicle’s load status and monitoring of each wheel end. Based on
wheel slip observed by the ABS during braking, braking forces at the axles are automatically adjusted to
achieve a balanced, e󰀩cient use of the brakes. This results in improved stopping performance and allows
the vehicle to adjust for consistent brake feel independent of the load.

11
Introduction
3.3.5 Deep Snow and Mud Switch
A deep snow and mud option switch is included with ATC. This function increases available traction on extra
soft surfaces like snow, mud or gravel, by slightly increasing the permissible wheel spin.
Drivers use a deep snow and mud switch to select this feature. When this function is in use, the ATC
indicator lamp blinks continuously.
3.3.6 How ESC Works
If a vehicle becomes unstable, this intelligent system automatically intervenes to reduce rollover, skidding
and jackkning risk. The system detects instability through the use of onboard sensors measuring vehicle
dynamics and selectively applies foundation braking to correct vehicle heading and/or prevent rollover.
3.3.7 How HSA Works
Hill Start Aid (HSA) supports select automated manual transmissions in reducing/totally eliminating the
rolling back of the vehicle while launching on a grade. When requested from the transmission, HSA holds
pressure in the service brakes of all axles of the towing vehicle when the vehicle is standing still. HSA will
hold pressure for a maximum of three seconds following full release of the brake pedal. Communication
between the transmission and the ECU takes place via the J1939 data link.
HSA grade threshold parameters may be modied in the Transmission ECU. These parameters must be
reviewed with the transmission manufacturer prior to making any modications in order to ensure safe
operation.
3.3.8 System Layout
A typical WABCO SmartTrac™ hydraulic ABS installation is illustrated below.
4011783a
ABS SENSOR CABLE
MASTER
CYLINDER
FRONT OF
VEHICLE
SENSOR
ASSEMBLY
HYDRAULIC
BRAKE LINE
ABS
MODULATOR
ASSEMBLY
ECU
BRAKE
BRAKE
BRAKE
BRAKE
HYDRAULIC BRAKE LINE
The ABS modulator assembly must be mounted below the master cylinder and above the brake calipers
and wheel cylinders.

12
Introduction
WABCO requires that the motor axis is positioned at an angle between +0 degrees and +10 degrees
with the horizontal plane, with the motor end pointing up and between -20 degrees and +20 degrees of
rotation of the motor axis. Contact the OEM or WABCO for additional information regarding the modulator
assembly’s orientation.
4013016a
0°±20°
360°
Z
1:2
5°±5°
±X
±Y
3.4 System Components
The SmartTrac™ hydraulic ABS unit consists of an electronic control unit (ECU) mounted directly on a
modulator assembly. The assembly is manufactured and sold as one part. Replacement of the individual
components is not available.
3.4.1 Electronic Control Unit (ECU)
The electronic control unit (ECU) processes sensor signals and generates solenoid valve commands to
reduce, maintain or reapply brake pressure.
4011784a
SmartTrac™
ECU

13
Introduction
3.4.2 Modulator Assembly
CAUTION
The modulator assembly contains brake uid. Handle the modulator assembly with appropriate
care. Do not expose the modulator assembly to impact loads or excessive vibrations. Do not blow
compressed air into the hydraulic ports. Mishandling the modulator assembly may lead to component
damage and system failure.
The modulator assembly houses the system’s solenoid control valves. There are three valves per wheel,
including an inlet and outlet for controlling ABS and the third to control ATC (rear axle only). The modulator
assembly also includes a pump motor, two low pressure accumulators and six ttings. Details about the
ttings can be seen below.
1 2 3 4
5
6
4011785a
Recommended tightening torque for the above mentioned ttings, known as thread savers, is
15 +2.2 ft-lb (20 +3 Nm).
Recommended tightening torque for brake line tube nuts is 11 +2.2 ft-lb (15 +3 Nm).

14
Introduction
3.4.3 Sensors
3.4.3.1 Sensor with Molded Socket
Used to measure the speed of a tooth wheel rotating with the vehicle wheel.
Produces an output voltage proportional to the wheel speed.
1004685a
3.4.3.2 Sensor Spring Clip
Holds the wheel speed sensor in close proximity to the tooth wheel.
1004686a
3.4.3.3 Tooth Wheel
A machined or stamped ring mounted to a machined surface on the hub of each ABS-monitored wheel.
This can also be referred to as a tone ring.
1004687a

15
Introduction
3.4.3.4 Steering Angle Sensor
The steering angle sensor (SAS) is part of the ESC system. The SAS delivers the driver’s steering input
(steering wheel position) to the ECU using a dedicated ESC system internal datalink. The ECU supplies
the sensor with voltage and ground. The SAS must be calibrated using diagnostic tools whenever it is
replaced, or when any vehicle steering components are replaced or adjusted.
4006873a
3.4.3.5 Electronic Stability Control (ESC) Module
The ESC module is part of the ESC system. It measures the vehicle yaw rate as well as vehicle lateral
acceleration. The ESC module includes part of the ESC control algorithm. It exchanges data with the
ECU via the ESC system internal data link. The ECU supplies the module with voltage and ground. The
ESC module must be initialized by diagnostic tools whenever the ECU or the ESC module is replaced.
4015103b
3.4.3.6 HSA Lamp
A multiplexed HSA lamp provides the driver with a visual indication of system deactivation and/or
active fault. If the lamp is hard wired, it must be an incandescent lamp or LED with a resistor to prevent
the ECU from setting a fault code. A failure detected on any of these components will lead to no HSA
availability.

16
Introduction
3.4.3.7 ABS and ATC Warning Lamps
Located on the vehicle instrument panel.
The ABS warning lamp illuminates for 3 seconds while performing a self check when the ignition is
turned on. It also illuminates when there is a fault.
The ATC warning lamp will remain on continuously if ATC is disabled due to a failure. The ATC lamp will
ash when ATC is active. See the “How ATC Works” section of this manual for details about ATC.
ABS and ATC warning lamps are included as part of the instrument cluster provided by the vehicle
manufacturer. Indicators are activated through the J1939 CAN system.
ESC and ATC may share the same lamp or separate lamps depending on the OEM and vehicle. Please
refer to OEM documentation for lamp operation on your vehicle.
1004689b
ABS WARNING LAMP
4011789b
OR
ATC WARNING LAMP
TC

17
Troubleshooting and Testing
4 Troubleshooting and Testing
4.1 Maintenance
4.1.1 General Information
There is no regularly scheduled maintenance required for the WABCO SmartTrac™ hydraulic ABS unit.
However, ABS does not change current vehicle maintenance requirements. For example, it is important that
the vehicle brake uid level be correctly maintained and regularly changed per the vehicle manufacturer’s
maintenance requirements.

18
Troubleshooting and Testing
4.2 Wiring Diagrams
4.2.1 System Wiring Information
The SmartTrac™ hydraulic ECU connector pin identication is below. Wiring may vary according to
the vehicle. Refer to the vehicle specications in the vehicle manual for specic wiring diagrams. The
SmartTrac™ hydraulic ABS wiring diagram appears on the next page.
4011786b
123456789101112131415
31
33 34 35 36 37 38 39 40 41 42 43 44 45 46
3029282726252423222120191817
32
16
47
PIN IDENTIFICATION FOR HYDRAULIC ABS WIRE HARNESS CONNECTORS TO THE ECU
Count from the pin number at the end of each row, identify pin assembly to measure.
Connector view shows the back of the harness connector.
Pin# Circuit Label
1 Pump Motor Supply 12v+ (KL30_P)
2 Not Used
3 Not Used
4 Not Used
5 Not Used
6 Not Used
7 Not Used
8 Ignition 12v (IGN)
9 Not Used
10 Not Used
11 Not Used
12 J1939 + High (CAN_1H, Vehic. Bus)
13 J1939 – Low (CAN_1L,Vehic. Bus)
14 ATC Switch (ATC Switch In)
15 Not Used
16 Not Used
17 Not Used
18 CAN_2H
19 CAN_2L
20 Not Used
21 Not Used
22 SC Supply
23 Not Used
24 Not Used
Pin# Circuit Label
25 Not Used
26 Not Used
27 Not Used
28 Not Used
29 SC GND
30 Not Used
31 Not Used
32 Solenoid Valve Supply 12v+ (KL30_VS)
33 Front Right Wheel Speed Sensor (FR iGM)
34 Front Right Wheel Speed Sensor (FR iG)
35 Not Used
36 Rear Left Wheel Speed Sensor (RL IG)
37 Rear Left Wheel Speed Sensor (RL IGM)
38 Not Used
39 Not Used
40 Not Used
41 Not Used
42 Rear Right Wheel Speed Sensor (RR IGM)
43 Rear Right Wheel Speed Sensor (RR IG)
44 Not Used
45 Front Left Wheel Speed Sensor (FL IG)
46 Front Left Wheel SpeedSensor (FL IGM)
47 Ground

19
Troubleshooting and Testing
4011787b
(KL_30) BATT
(KL_31) GND
(KL_15) IGNITION
(CAN_1 H) J1939 H
(CAN_1 L) J1939 L
IGNITION FUSE 1A
RF IG RF IGM LF IG LF IGM RR IG RR IGM LR IG LF IGM IGN ATC SWITCH IN SC SUPPLY SC GND CAN_2H CAN_2L CAN_1H. VEHICLE BUS CAN_1L. VEHICLE BUS KL30_P KL30_VS GND
33 45 46 43 42 36 37 81
41
213132 4734
SENSOR
FRONT
RIGHT
2x0.75 mm2 TWISTED
SENSOR
FRONT
LEFT
2x0.75 mm2 TWISTED
SENSOR
REAR
RIGHT
2x0.75 mm2 TWISTED
SENSOR
REAR
LEFT
2x0.75 mm2 TWISTED
WIRING DIAGRAM SmartTrac™ HYDRAULIC ABS
SAS ESC
22 29 18 19
1
3
6
5
4
3
2
1

20
Troubleshooting and Testing
4.3 System Diagnostics
4.3.1 WABCO TOOLBOX™ Software
Use WABCO’s PC-based diagnostic program, TOOLBOX™ Software, to diagnose SmartTrac™ hydraulic
ABS faults and trouble codes. The software runs in Windows®XP, Vista, Windows®7, 8 and 10. It is used
to display system faults, wheel speed data, test individual components, verify installation wiring, enable and
disable system functions, view counters and more.
The TOOLBOX™ Software is available for purchase at https://wabco.snapon.com. Follow the instruction
and correctly install the software. Once you have TOOLBOX™ Software installed on your computer, follow
the on-screen repair information to make the necessary repairs or replacements. See the following section
for basic fault identifying and system testing instructions.
A J1939 cable and USB vehicle communication interface adapter are required to connect the
PC to the J1939 vehicle bus while performing diagnostics.
For complete instructions for using this program, refer to the User’s Manual at
https://zf.com/cvliterature under Service and Support, TOOLBOX™ Software. Contact the
WABCO Customer Care Center at 855-228-3203 for information about TOOLBOX™ Software.
4.3.2 SmartTrac™ Hydraulic ABS Main Screen and Menus
Select Hydraulic ABS from the TOOLBOX™ Software Main Menu. TOOLBOX™ Software will read and
identify the type of ECU being used and displays the SmartTrac Hydraulic screen.
4.3.2.1 Main Screen
This screen provides product information (ECU part number, serial number, software version, etc.),
component data, wheel sensor data, sensor status and pull-down menu selections.
ECU information is read once from the ECU and does not change. All other information (e.g.,
wheel sensors, voltages and fault information) is read and updated continuously.
4.3.2.2 Pull-Down Menu Selections
System
Adapter Selection: Select the adapter used to interface between the vehicle, the communication
connector and the laptop. The protocol for SmartTrac™ hydraulic is J1939.
Exit: Exit the program.
Display
Diagnostic Trouble Codes: Displays the faults and trouble codes, along with SPN and FMI numbers that
can be referenced in the system reaction codes and repair instructions listed in Appendix.