2021 Toyota Prius Cruise Control Isn't Working

Troubleshooting Common Issues with Cruise Control in Your 2021 Toyota Prius and How to Fix Them

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Reviewed by
Devin Cabugcal
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
0%
25% chance it's the
Control Module
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25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 2021 Toyota Prius cruise control isn't working are failed control module, sensor or switch issues, or throttle actuation problems.
  • Sensor: A faulty or malfunctioning sensor can lead to incorrect readings, causing issues with engine performance or other systems relying on accurate data.
  • Control Module: A faulty control module can lead to erratic vehicle behavior or failure of various electronic systems due to improper signal processing.
  • Throttle: A faulty throttle body or a defective accelerator pedal position sensor may be causing inconsistent throttle response.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2021 Toyota Prius cruise control isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

In the event that a wheel speed sensor fails, the ABS, traction control system (TCS) and manufacturer specific stability control system lights will illuminate, informing the driver that the systems are disabled. The vehicle will be more prone to tire slip, and normal driving patterns may need to be adjusted to correct for the loss of computer control. On older vehicle's, the speedometer can be affected, causing illumination of the check engine light as well.

The cruise control switch can cause complete failure of the cruise control feature, but in a lucky scenario only partial functionality will be lost. This means that the cruise control may come on, but that it will not increase in speed automatically, or the cancel button does not work leading the driver to cancel cruise control with the foot brake. In some vehicles, the cruise control light may illuminate, or a warning message may be displayed due to lack of functionality.

What are the initial diagnostic steps to take when the cruise control isn't working on a 2021 Toyota Prius?

When faced with a malfunctioning cruise control system in your 2021 Toyota Prius, it's important to approach the diagnosis methodically. Begin by checking the cruise control fuse located in the fuse box; a blown fuse can often be the simplest fix. Next, inspect the cruise control buttons on the steering wheel to ensure they are operational, as any malfunction here can prevent the system from engaging. The speed sensor is another critical component, so verify its functionality, as it directly influences cruise control performance. Additionally, examine the brake lights; if they are not working correctly, this can inadvertently disable the cruise control system. Utilizing an OBD-II scanner to check for error codes can provide valuable insights into any underlying issues. Finally, look for mechanical problems such as a stuck throttle or damaged wiring, as these can also hinder cruise control operation. By following these steps, you can effectively diagnose and potentially resolve the cruise control issue on your Prius, saving time and money on repairs.

What are the common problems that could cause the cruise control to stop working in a 2021 Toyota Prius?

When troubleshooting cruise control issues in a 2021 Toyota Prius, it's essential to understand the common problems that may be at play. One frequent culprit is a faulty brake light switch, which can prevent the cruise control from engaging since the system is designed to disengage when the brake pedal is pressed. Additionally, speed sensor issues can disrupt the cruise control's ability to maintain a constant speed, leading to malfunction. A blown fuse in the cruise control system can also be a straightforward yet often overlooked reason for failure. Furthermore, problems with the throttle control system can hinder the cruise control's performance, making it difficult to maintain speed. Lastly, if the Electronic Control Module (ECM) is experiencing issues, it can affect various functions, including cruise control. By identifying and addressing these common problems, you can effectively diagnose and potentially resolve the cruise control issues in your Prius, ensuring a smoother driving experience.

How urgent is it to address the malfunctioning cruise control in a 2021 Toyota Prius?

Addressing a malfunctioning cruise control in a 2021 Toyota Prius is of utmost importance due to the safety risks it poses. A malfunction can lead to unexpected acceleration or deceleration, which can create hazardous driving conditions for both the driver and others on the road. Additionally, a faulty cruise control system diminishes the convenience and enjoyment of driving, as it disrupts the intended functionality of this feature. Ignoring these symptoms not only compromises safety but can also lead to more severe issues within the vehicle's systems, resulting in costly repairs down the line. Therefore, it is crucial to prioritize the diagnosis and repair of cruise control problems promptly to ensure a safe and reliable driving experience.

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