1 Introduction
1
Meritor WABCO Maintenance Manual MM-0112 (Revised 07-05)
1 Introduction
Contents
This manual contains service information for E version Meritor
WABCO Anti-Lock Braking System (ABS) and ABS with Automatic
Traction Control (ATC) for trucks, tractors and buses. E version ABS
incorporates Power Line Carrier Communication (PLC), an optional
feature that allows tractor/trailer communication. For the driver, this
means that a trailer ABS indicator lamp located on the vehicle dash
will come on if a trailer ABS fault occurs on a trailer equipped
with PLC.
NOTE: For diagnostic and testing procedures for systems with
C version ECUs, use Maintenance Manual 28, Anti-Lock Braking
Systems (ABS) for Trucks, Tractors and Buses. For D version ECUs,
use Maintenance Manual 30, Anti-Lock Braking Systems (ABS) 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 ArvinMeritor’s Customer Service Center at
800-535-5560.
Figure 1.1
Description
How ABS Works
Meritor 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.
Two ABS indicator lamps, one for tractor and one for trailer, let
drivers know the status of the system. The tractor ABS lamp is also
used to display tractor blink code diagnostics. Figure 1.2. The
location of the ABS indicator lamps varies depending on the make
and model of the vehicle.
Figure 1.2
If the vehicle is equipped with optional Automatic Traction Control
(ATC), or with ATC and Roll Stability Control (RSC), the ATC indicator
lamp is used to indicate both ATC and RSC. Refer to Section 2.
Blink code diagnostics information for trailer ABS is not included in
this manual. Refer to Maintenance Manual 33, Easy-Stop™ Trailer
ABS, or Maintenance Manual MM-0180, Enhanced Easy-Stop™
Trailer ABS with PLC, for trailer diagnostics.
Figure 1.1
E
MANUFACTURING
INFORMATION
PART
NUMBER
ECU
VERSION
ABS
CONFIGURATION
4003972a
Figure 1.2
Do not open the ECU. Opening the ECU to gain access to the
internal components will void the warranty.
1002000a
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