Lexus EPB Activation Stopped Incompletely: Causes & Fixes

Electronic Parking Brakes (EPB) is a perfect example of innovation in the automotive industry.

Not too long ago, most cars made use of manual hand brakes. Today, we can command our vehicle to lock its rear brakes with a button.

However, technological advancement comes with its challenges. 

This article will discuss the meaning, symptoms, causes and fix for the EPB Activation Stopped Incompletely error message in Lexus and Toyota. Let’s get right into it!

What is EPB Activation Stopped Incompletely error message all about?

Before we look at the meaning of this error message appearing on your instrument cluster, let’s begin with EPB.

Electronic Parking Brake (further referred to as EPB) is an electronically controlled parking brake system.

The driver activates the EPB by holding a button, and the brake pad at the rear side is electronically applied.

This system is more energy efficient than the former manual hand brake. The EPB relied on the actuator and electronic control unit (ECU) to function well. 

So, why are you seeing this error on your information cluster?

The “EPB Activation Stopped Incompletely Message” will appear on the information cluster of your Lexus or Toyota when the parking brakes have developed faults.

To confirm that your EPB has developed faults, turn “on and off” your EPB button multiple times. It should reset the EPB system, and the warning signs should disappear from the cluster.

If it doesn’t, then there is a problem with your vehicle’s parking brake, and you should read further. 

Note: Before troubleshooting, the Toyota Basic warranty covers this repair. 

Vehicles under 36 months or 36,000 miles, whichever comes first, are covered and troubleshooting yourself may void this cover.

Symptoms of “EPB Activation Stopped Incompletely Message” in your Toyota or Lexus

The obvious sign of EPB malfunction in your vehicle is the error message that appears on your information cluster.

If the error message does not go away after resetting, it is most certainly that the EPB is faulty.

Another symptom is the flashing parking brake warning light on your vehicle dashboard.

During diagnostic scanning, you may have DTC C059746 stored in the vehicle ECU.

Causes of the “EPB Activation Stopped Incompletely Message” in your Toyota or Lexus

The following are the causes of the error message on your dashboard display.

Corroded brake cable

Corrosion is a major issue with braking cables as they age. We recommend taking your vehicle to a mechanic for brake system inspection at least once a year.

Firstly, physically inspect the capable conditions. Check for cuts, short circuits and other deteriorating states that can affect the power supply to the EPB.

Inspect the cables running to the actuator, ECU, and switches are in good conditions.

Low or High Voltage

The EPB relies on electric power supplies by the battery to engage and disengage the rear brakes.

Therefore, a power supply below or above the threshold may trigger the error message on your information cluster.

Using a multimeter, examine the voltage of the battery terminal. While the engine is off, you should ideally get 12.4V to 12.9V.  

In addition, while the engine is idle, the battery voltage should read between 13.7- 14.7V.

Any figure above or below the threshold shows an issue with the battery.

Furthermore, a weak battery, corroded cable or broken actuators may trigger the error message.

Damaged EPB Switch

The parking brake system relies on the brake to send commands to the ECU to engage or disengage the rear brakes.

A faulty switch means the EPB cannot properly communicate with the control module.

Furthermore, a bad EPB switch will impact the brake light, torque converter control system and all other control modules within the EPB system.

EPB and ECU miscommunication

The EPB relies on the actuator and Engine control unit (ECU) to generate the right amount of force the brakes need.

Inconsistencies or miscommunication between the two systems can trigger the error message.

The first step is to evaluate the operating condition of the ECU and actuator. You can physically examine if the actuator is damaged.

Or you can use an OBD II scan tool to diagnose the fault with the ECU and actuator.

Faulty fuse

Most electrical components in your vehicle have a dedicated fuse, including the EPB. 

For the EPB, check the fuse box near the engine compartment and the car battery.

You will need a multimeter to inspect whether the fuse is functioning well. If there is no current within the fuse, replace it with a new one.

Remedies for EPB Activation Stopped Incompletely Message

The EPB system relies on the Actuator and ECU for operational function. 

First, physically inspect the actuator, battery and wiring for damages and faults.

If any damage is noticed on the listed components, we recommend you fix or replace the damaged item.

Next, run diagnostic testing on the vehicle to fix the EPB Activation stopped Incompletely message. 

You will require one of the Toyota Techstream software to run a diagnostic scan. Using the scan tool check for the stored presence of DTC C059746. 

The presence of the stored code alongside the error message means that there is a parking brake malfunction. 

Confirm that the skid control computer calibration is updated and running on the latest software.

If not, you must flash reprogram the skid control computer calibration. Ensure to maintain the 13.5V battery voltage as required for flashing.

Next, install the authorized modification label onto the vehicle.

And finally, test drive the vehicle to confirm the error message has disappeared and the car is operating properly.

Final Thought!

We examined the EPB Activation Stopped Incompletely message. We encourage our readers to take all error messages on their vehicle dashboards seriously. 

Such warning signs may inform you of a serious problem affecting the car’s drivability and safety. 

As seen above, many issues can trigger the error message above. If the error persists after following all the instructions listed above, visit a mechanic to diagnose your Electronic parking brake system comprehensively.

  • Edmond Davis

    I'm Edmond Davis, an automotive expert with years of experience in vehicle repair, performance, and safety. I graduated from the University of Michigan with a degree in Automotive Engineering and have worked with major companies like Ford, GM, and Chrysler. I'm a trusted source of information for anyone looking to learn more about cars or improve their driving experience.

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