25834221 | Genuine GM® AntiLock Brake Module For Silverado 1500 - 2009-2014

1. Monitors wheel speed

Wheel speed sensors send signals to the module many times per second.

2. Detects wheel lock-up

If one or more wheels slow down too quickly (about to skid), the module identifies that as lock-up.

3. Controls brake pressure

The module rapidly pulses the brake pressure through hydraulic valves:

• Reduces pressure to a wheel starting to lock

• Reapplies pressure when traction returns

This action happens many times per second—much faster and more precisely than a human could pump the brakes.

4. Helps maintain vehicle control

By preventing wheel skid, the ABS module allows:

• Straighter stopping

• Steering control during hard braking

• Better stability on wet or slippery surfaces

The ABS light on the dashboard is the most common sign.
Sometimes the Traction Control or Stability Control light also turns on because those systems rely on the ABS module.

2. Brakes Lock Up Under Hard Braking

If the module fails, the ABS system may not activate.
The wheels can lock up, causing skidding or loss of steering during emergency stops.

3. Unresponsive or Weak ABS Operation

On slippery surfaces, you may notice:

• No ABS pulsation in the brake pedal

• The ABS doesn’t “kick in” like it should

4. Increased Stopping Distance

Without proper ABS control, the vehicle can take longer to stop, especially on wet or icy roads.

5. Brake Pedal Feels Abnormal

A failing module or its hydraulic control unit can cause:

• Pulsating even when not braking hard

• A soft/spongy pedal

• A hard, unresponsive pedal (less common)

6. Speedometer Problems (in some cars)

Some vehicles rely on the ABS module for speed data. If the module fails, the speedometer may stop working or behave erratically.

7. Traction Control or Stability Control Failure

Systems like ESC, TCS, and VSC use the ABS module.
If the module goes bad, you may see:

• “TRAC OFF”

• “ESC OFF”

• “Stability Control Disabled”

8. Wheel Speed Sensor Codes (Even If Sensors Are Good)

A failing ABS module may misread wheel sensor signals, causing false sensor trouble codes.