A100039239 | Genuine Bendix ABS Trailer Valve Assembly TABS-6

An ABS Trailer Valve Assembly A100039239 is the brain and control valve of the trailer’s anti-lock brake system, helping the trailer stop safely without skidding. Related Part Numbers: BXK109808, 0468500160, 0468500182

General Specifications

Specifications

TABS-6 ABS Kit for Trailers

Purpose & Function

1. Prevent Wheel Lockup

During hard braking:

• The ECU detects if a wheel is about to stop rotating.

• The valve rapidly adjusts air pressure to that wheel.

This prevents skidding.

2. Improve Trailer Stability

It helps:

• Prevent trailer swing

• Reduce risk of jackknifing

• Keep the trailer tracking straight behind the tractor

3. Maintain Steering & Control

Even though the trailer doesn’t steer, preventing lockup:

• Keeps the trailer stable

• Prevents loss of directional control

• Reduces loss of traction on wet or icy roads

4. Reduce Tire Wear

Locked wheels cause:

• Flat spots

• Rapid tire damage

ABS prevents that by keeping wheels rotating during braking.

5. Meet Legal Requirements

In many countries, including the U.S., ABS has been required on most air-brake trailers since the late 1990s.

Signs of a Bad ABS Trailer Valve

1. ABS Warning Light Stays On

• Trailer ABS light stays illuminated on the trailer

• ABS warning stays on in the tractor dash

This is the most common symptom.

2. Wheels Lock Up During Hard Braking

If ABS is not functioning:

• Trailer wheels may skid

• You may see flat spots on tires

• Trailer may feel unstable under heavy braking

3. No ABS Self-Check Click

When you first power the trailer (key on), you should often hear:

• A brief clicking or cycling sound from the ABS valve

If there’s no sound, the valve may not be activating.

4. Air Leaks from the Valve

A failing modulator valve may:

• Leak air constantly

• Leak only during brake application

• Leak from exhaust ports

Air leaks can reduce braking performance.

5. Intermittent ABS Operation

• ABS light turns on and off

• Braking feels inconsistent

• Fault appears only during wet conditions

Could indicate internal valve or ECU failure.

6. Fault Codes (Most Accurate Method)

Using a diagnostic tool, you may see:

• Modulator valve faults

• ECU internal failure codes

• Power/ground communication faults

This is the most reliable way to confirm failure.

7. Poor Trailer Stability During Braking

• Trailer pulls to one side

• Feels like brakes are grabbing unevenly

• Increased risk of trailer swing

About Bendix

Bendix is a leading manufacturer of air brake systems, safety technologies, and control components for commercial trucks, buses, and trailers. Known for innovations in braking, stability, and traction control, Bendix supplies OEM and aftermarket parts across North America. It is a subsidiary of Knorr-Bremse, a global leader in braking systems.