25021217674 | Genuine Volkswagen® ABS Pump Assembly 2010-2013

1. Restore Brake Pressure After ABS Releases It

When the ABS activates, it temporarily releases brake pressure to prevent wheel lock-up.
The pump then rebuilds and restores that pressure so braking can continue smoothly.

2. Allow Rapid Brake Pulsing

The ABS pump enables the system to:

• Apply

• Release

• Reapply
  brake pressure multiple times per second, giving you maximum stopping power without losing traction.

3. Maintain Steering Control During Hard Braking

By preventing wheel lock-up, the pump helps keep the vehicle steerable on slippery or emergency stops.

4. Support Traction Control and Stability Systems

ABS pumps are also used by:

• Traction Control (TCS)

• Electronic Stability Control (ESC)

They adjust brake pressure to help maintain grip and vehicle stability.

1. ABS Warning Light On

• The ABS light stays on or appears while driving.

• Often the first and most common sign of pump failure.

2. Brake Pedal Feels Hard or Unresponsive

• When ABS should activate, the pedal may become very stiff.

• The pump may not build pressure correctly.

3. ABS Activates at the Wrong Time

• You may feel pulsations or vibrations in the brake pedal even during normal braking.

• Sometimes the pump acts like the car is sliding when it isn’t.

4. No ABS Function During Hard Braking

• Wheels may lock up under heavy braking.

• The pedal may not pulse like it normally would during ABS activation.

5. Strange Noises From the ABS Unit

• A failing pump can make:

  • Grinding noises

  • Buzzing that lasts too long

  • Clicking sounds

• The pump may struggle or fail to run.

6. ABS Pump Running Constantly

• If the pump motor runs nonstop, even when you’re not braking, it may be stuck on due to internal failure.

7. Brake System Codes on a Scan Tool

• Trouble codes related to pump motor failure, hydraulic pressure faults, or pump relay issues.