How to Troubleshoot and Replace a Faulty Brake Actuator in a 2010-2015 Toyota Prius


If you own a 2010-2015 Toyota Prius and you’re hearing an abnormal pump or buzz noise coming from your car, it might be time to inspect your brake actuator. A faulty brake actuator can not only lead to a lit-up dashboard but also severely affect braking performance. This article serves as a comprehensive guide for troubleshooting and replacing a faulty brake actuator in a 3rd-generation Toyota Prius.

Identifying the Problem: Is it the Brake Actuator?

Before diving into repairs, it’s important to diagnose the issue correctly. A common symptom is a recurring pump or buzz noise every 10-15 seconds, which can become more frequent over time. An ABS code for low accumulator pressure can also indicate an issue with your brake actuator. If you encounter these signs, consult a professional or plug in a high-level scan tool to confirm the diagnosis.

The Cost of Inaction

Ignoring the signs can lead to a lit-up dashboard, an abnormal brake feel, and the loss of regenerative braking. In one firsthand account, a Prius owner was quoted a staggering $4,500 for a professional repair. However, if you’re willing to get your hands dirty, you can fix the issue for as low as $130.

The Replacement Process: A Step-by-Step Guide

Required Tools and Parts

  • 10mm and 12mm impacts
  • Pliers
  • Pry tool
  • Line wrenches
  • Brake fluid
  • High-level scan tool (for system bleeding and recalibration)

Preliminary Steps

  1. Disconnect the high voltage and 12V batteries.
  2. Remove the wiper cowl and wiper assembly for better access.

Removing Old Parts

  1. Brake Fluid Reservoir: Use a 10mm impact to unbolt and drain it. Disconnect the hoses to prevent spills.
  2. Booster Assembly: Disconnect the bracket and brake lines. Maneuver the assembly out carefully.
  3. Brake Actuator: Disconnect hoses and electrical connectors. Use a 12mm impact to remove the four bolts holding it in place. Remove the actuator arm from the brake pedal.

Installing New Parts

  1. Install the new pump by aligning and rocking it into place.
  2. Reinstall the booster assembly, carefully feeding through the brake lines and bolting it back.

Final Steps: Bleeding and Recalibration

After installation, you’ll need to bleed the brake system and recalibrate the linear solenoid valve. A high-level scan tool is highly recommended for this process due to additional tests and relearn procedures it offers.

Real-world Experience and Tips

One Prius owner, who had never done any brake work before, successfully replaced the brake actuator in his 2011 model over two days. If you’re the least bit handy, this task is 100% doable. Purchasing a used brake actuator with the same part number can help you avoid the need for reprogramming. If you don’t want to tackle the job yourself, consider buying a used part and having a mechanic do the work for around $500.


The brake actuator is a crucial component that affects your Prius’ braking performance. Diagnosing and fixing a faulty brake actuator is not as daunting as it sounds, especially when you compare the cost of DIY repair to what dealerships charge. With the right tools and a bit of patience, you can restore your Prius back to optimal performance.