This manual describes how Meritor 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:

· Easy-Stop™ Basic (2S/1M without external diagnostics): TP-97145

· Easy-Stop™ Standard (4S/3M with external diagnostics): TP-97153

This manual contains blink code diagnostics information and instructions for most of the ECU/Valve Assemblies listed in Table A-Scope of Blink Code Diagnostics. The serial and part numbers are located on the ECU/Valve Assembly. Refer to Figure 1.1.

Easy-Stop™ Trailer ABS Parts

Parts book PB-96133 lists Meritor WABCO Easy-Stop™ replacement parts. To obtain a copy, contact the Meritor Customer Support Center at 800-535-5560.

Meritor 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 Meritor 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.

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.

An ABS warning lamp lets drivers know the status of the system.