745-K070958 | Genuine Bendix® Traction Relay Valve

1. Fast brake application and release

Like a standard relay valve, the ATR-6 is mounted close to the brake chambers. It allows air to flow directly from a nearby air reservoir to the brakes instead of traveling all the way from the foot valve, which:

• Reduces braking delay
• Improves brake response
• Helps the vehicle stop more predictably

2. ABS operation

When the ABS detects that a wheel is about to lock during braking, the electronic controller can command the ATR-6 to adjust brake pressure at that axle.
This helps:

• Prevent wheel lockup
• Maintain steering control
• Reduce skidding

3. Traction control

When a drive wheel spins on a slippery surface (snow, ice, mud, wet pavement), the traction control system can use the ATR-6 to apply brake pressure to the spinning wheel.
This:

• Transfers torque to the wheel with better grip
• Helps the truck get moving
• Improves stability during acceleration

1. Air leak near the valve

One of the most common failures is an internal or external air leak.

Symptoms:

• Hissing sound around the valve
• Air system takes longer to build pressure
• Compressor runs more frequently
• Difficulty maintaining air pressure when parked

2. ABS warning light

If the electrical solenoid or wiring associated with the ATR-6 fails, the ABS controller may detect a fault.

Symptoms:

• ABS light stays on
• Stored ABS fault codes
• ABS system becomes disabled

3. Traction control warning light

Because the ATR-6 is used for traction control on many trucks, a failure can trigger:

• Traction control warning lamp
• Loss of automatic traction assistance on slippery roads

4. Brakes apply slowly or release slowly

The relay-valve portion may stick internally.

Symptoms:

• Delayed brake response
• Brakes dragging after pedal release
• Uneven brake feel

5. Drive axle brakes behave abnormally

A sticking or malfunctioning ATR-6 may cause:

• One axle braking harder than expected
• Erratic brake application
• Unexpected wheel lockup under some conditions

6. Poor traction on slippery surfaces

If the traction-control function isn't working:

• Drive wheels spin more easily
• Reduced ability to start on snow, ice, gravel, or mud
• Truck gets stuck more readily

7. ABS fault codes related to pressure modulation

Common diagnostic systems may log faults involving:

• Traction relay valve circuit
• ABS modulator performance
• Solenoid open circuit
• Solenoid short circuit
• Valve response errors