2015 Toyota Prius C Cruise Control Not Working

Common Causes of Cruise Control Malfunctions in Your 2015 Toyota Prius C and How to Fix Them

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Reviewed by
Aisha
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 C 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 C 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 steps to diagnose the cruise control issue in a 2015 Toyota Prius C?

To effectively diagnose cruise control issues in your 2015 Toyota Prius C, begin with the simplest checks before moving on to more complex diagnostics. Start by inspecting the brake pedal switch, as a malfunction here can prevent cruise control from activating. Next, examine the fuse box for any blown fuses related to the cruise control system, as this could indicate an electrical issue. If the fuses are intact, verify the functionality of the speed sensor, since inaccurate readings can disrupt cruise control operation. For vehicles with mechanical systems, check the vacuum actuator and throttle cable for any signs of damage or leaks. Additionally, inspect the clock spring in the steering wheel, as a failure here can affect the cruise control buttons. Ensure that all wiring and connectors are secure and undamaged, as loose connections can lead to system failures. If your Prius C is equipped with Dynamic Radar Cruise Control, clean the radar sensor and check for error codes using an OBD-II scanner. Finally, test the cruise control switch to see if it activates the system. By following this structured approach, you can systematically identify and address the underlying issues affecting your cruise control system. If problems persist after these checks, seeking professional assistance may be necessary.

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

When troubleshooting cruise control issues in a 2015 Toyota Prius C, it's essential to consider several common problems that may be at play. One frequent culprit is the clock spring, a vital component that connects the steering wheel controls to the vehicle's electrical system. If this spiral cable malfunctions, it can disrupt the functionality of the cruise control buttons. Additionally, battery and electrical issues can lead to cruise control failure; a weak or dead 12-volt battery can prevent the system from operating correctly, making it crucial to ensure the battery is in good condition. Faulty sensors, including speed, ABS, or steering angle sensors, can also interfere with cruise control, as can blown fuses associated with these components. For models equipped with dynamic radar cruise control, problems with the radar sensor or software glitches may trigger error messages, indicating that the system is unavailable. Furthermore, the cruise control switch itself may have dirty or worn contacts, which can sometimes be remedied by toggling the switch on and off. Lastly, issues related to the airbag system or steering wheel assembly can impact cruise control functionality, particularly if recent maintenance has knocked sensors out of alignment. By systematically checking these areas, DIYers can effectively diagnose and address the underlying causes of cruise control malfunctions in their Prius C.

How urgent is it to address the malfunctioning cruise control in a 2015 Toyota Prius C?

Addressing a malfunctioning cruise control in a 2015 Toyota Prius C should not be overlooked, as it can lead to several complications if neglected. While the immediate safety risk may seem low, the malfunction could indicate underlying issues such as a faulty brake pedal switch or speed sensors, which are critical for the vehicle's overall functionality. Ignoring these symptoms could result in more severe problems, including inaccurate speed readings or electrical malfunctions that affect other systems. Additionally, the absence of cruise control can make long drives more tiring, reducing driver comfort and increasing fatigue. Therefore, it is advisable to diagnose and repair the issue promptly, not only to restore the convenience of cruise control but also to prevent potential damage to other components, ensuring the vehicle remains safe and reliable for future journeys.

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