WABCO ESC - 1 Section 1: Introduction; System Components; Electronic Control Unit (ECU); Wheel Speed Sensing Systems

1 Introduction
1
WABCO Maintenance Manual MM-0112 (Revised 07-18)
1 Introduction
Contents
This manual contains service information for the following systems.
앫 E version WABCO Anti-Lock Braking System (ABS)
앫 Automatic Traction Control (ATC)
앫 Roll Stability Control (RSC)
앫 Electronic Stability Controls (ESC) for trucks, tractors and buses
The ABS version is marked on the ECU. Figure 1.1. If you cannot
identify the ECU version installed on your vehicle, contact WABCO
North America Customer Care at 855-228-3203.
Figure 1.1
For Additional Information
Diagnostic and testing procedures for other ECU versions can be
found in the following manuals.
앫 C version ECUs — Maintenance Manual 28, Anti-Lock Braking
Systems (ABS) for Trucks, Tractors and Buses
앫 D version ECUs — Maintenance Manual 30, Anti-Lock Braking
Systems (ABS) for Trucks, Tractors and Buses
Refer to the following manuals for Trailer ABS diagnostics and
information.
앫 Maintenance Manual 33, Easy-Stop™ Trailer ABS
앫 Maintenance Manual MM-0180, Enhanced Easy-Stop™ Trailer
ABS with PLC
Anti-Lock Braking System (ABS)
ABS is a system designed to provide and maintain the best possible
traction and steering control during an extreme braking event.
During a potential wheel lock event, the ABS ECU, using information
provided by the wheel speed sensors, sends a signal(s) to the
appropriate modulator valve(s) to hold, apply or release the brakes
as needed. ABS works automatically, the driver does not have to
select this feature.
System Components
Electronic Control Unit (ECU)
The ECU is the control center or “brain” of the ABS, RSC and ESC
systems. It receives information from the sensors, processes data
and sends signals to modulators and active braking valves to
achieve different tasks. Depending on the system and vehicle
configuration, ECUs are available for cab- or frame-mounted
applications and are divided into Basic Cab, Universal Cab, Frame
and Advance Frame models. RSC and ESC systems are only
available on universal and advance frame ECUs. Figure 1.2.
Figure 1.2
Wheel Speed Sensing Systems
Wheel speed sensing systems consist of a tooth wheel mounted on
the hub or rotor of each monitored wheel and a speed sensor
installed with its end against the tooth wheel. The sensor
continuously sends wheel speed information to the ECU. A sensor
clip holds the sensor in place and against the tooth wheel.
Figure 1.3.
Figure 1.1
4010603a
Figure 1.2
UNIVERSAL
ECU
FRAME-MOUNTED
ECU
BASIC
ECU
4003974a