2015 Toyota Prius Plug-In Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2015 Toyota Prius Plug-In 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
0%
25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 2015 Toyota Prius Plug-In 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 2015 Toyota Prius Plug-In 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 2015 Toyota Prius Plug-In?

When faced with a malfunctioning cruise control system in your 2015 Toyota Prius Plug-In, it's essential to adopt a systematic diagnostic approach. Begin by checking the cruise control fuse, as a blown fuse is a straightforward issue that can easily be resolved. Next, inspect the cruise control buttons on the steering wheel; ensuring they are functioning correctly can save you from more complex repairs. Following this, verify the speed sensor's operation, as it plays a crucial role in the cruise control system's functionality. Utilizing a diagnostic scanner to check for error codes can provide valuable insights into any underlying issues. Additionally, ensure that your brake lights are operational, as a faulty brake light switch can inhibit cruise control engagement. Finally, take a moment to inspect the wiring connections associated with the cruise control system for any signs of damage or looseness. By methodically addressing these areas, you can effectively diagnose and potentially resolve the cruise control issues in your vehicle.

What are the common problems that could cause the cruise control to stop working in a 2015 Toyota Prius Plug-In?

When troubleshooting the cruise control system in a 2015 Toyota Prius Plug-In, it's essential to understand the common problems that may lead to its failure. One of the primary culprits is a faulty brake light switch, which can disrupt the system's ability to engage by failing to signal when the brake pedal is pressed. Additionally, issues with the speed sensor can prevent the vehicle from maintaining a constant speed, directly affecting cruise control functionality. A blown fuse within the cruise control circuit can also halt its operation entirely, making it a straightforward fix. Furthermore, the throttle actuator, which regulates engine speed, may malfunction, leading to cruise control issues. Lastly, problems with the Electronic Control Module (ECM) can impact various vehicle functions, including cruise control. By identifying and addressing these potential issues, DIY enthusiasts can effectively troubleshoot and restore the cruise control system in their Prius Plug-In.

How urgent is it to address the malfunctioning cruise control in my 2015 Toyota Prius Plug-In?

Addressing a malfunctioning cruise control in your 2015 Toyota Prius Plug-In is of utmost urgency due to the significant safety risks it poses. A faulty system can lead to unpredictable acceleration or deceleration, which can be particularly hazardous on highways or in heavy traffic. This unpredictability not only increases the likelihood of accidents but also compromises your ability to maintain control over your vehicle's speed. Furthermore, timely intervention is crucial for preserving the overall performance and efficiency of your Prius. Ignoring the issue may result in further complications, potentially leading to more extensive and costly repairs down the line. Therefore, it is essential to prioritize the repair of your cruise control system to ensure your safety, enhance vehicle reliability, and avoid unnecessary expenses.

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2015 Toyota Prius Plug-In Cruise Control Issues & Repairs