400 500 430 0 | Genuine Wabco® Trailer IABS 2M Premium Valve

A Trailer iABS 2M Premium Valve 400 500 430 0 is a key part of a trailer’s anti-lock braking system (ABS)—it’s the unit that both controls braking electronically and modulates air pressure to keep the wheels from locking up. Trailer IABS 2M Premium Valve trailers with WABCO iABS 2M systems (2-modulator ABS setup)

General Specifications

Dry van trailers
Refrigerated (reefer) trailers

Flatbeds
Tank trailers
Most air-brake equipped commercial trailers

Purpose & Function

• 1. Prevents skidding
• When a wheel is about to lock, the valve quickly reduces brake pressure so the tire keeps rotating instead of sliding.

2. Maintains trailer stability
Helps keep the trailer tracking straight behind the tractor, reducing the risk of:

• Jackknifing
• Trailer swing or fishtailing

• 3. Improves braking control
• Instead of all-or-nothing braking, it applies precise, rapid adjustments to each side of the trailer.

• 4. Reduces stopping distance (in many conditions)
• Especially on wet or slippery roads, controlled braking is more effective than locked wheels.

• 5. Protects tires and components
• Prevents flat spots and excessive wear caused by locked brakes.

Signs of a Bad

1. ABS warning light stays on

• Trailer ABS light doesn’t go off after startup
• Indicates stored fault codes or system failure

2. Wheels lock up during braking

• Especially on wet or slippery roads
• Means ABS modulation isn’t working

3. Poor or uneven braking

• One side brakes harder than the other
• Trailer may pull or feel unstable

4. No ABS function at all

• Brakes work, but ABS is inactive
• System behaves like an old non-ABS trailer

About Wabco

WABCO (originally the Westinghouse Air Brake Company) is a global leader in vehicle control systems for commercial vehicles such as trucks, buses, and trailers. Founded in 1869 and later becoming a part of ZF Friedrichshafen AG in 2020, WABCO is best known for pioneering advanced braking, stability, and suspension technologies.