Toyota Prius Plug-In Cruise Control Isn't Working

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

Troubleshooting Cruise Control Issues in a Toyota Prius Plug-In

When troubleshooting cruise control issues in your Toyota Prius Plug-In, begin with the simplest solutions before delving into more complex diagnostics. Start by checking the fuse associated with the cruise control system, as a blown fuse is a common and easily fixable problem. Next, inspect the cruise control switches for any signs of malfunction; faulty switches can disrupt the system's operation. If these components are functioning correctly, turn your attention to the speed sensor, as issues here can prevent the cruise control from engaging properly. If the speed sensor checks out, consider examining the control module or Engine Control Module (ECM), as these can also be culprits in cruise control failures. Additionally, ensure that all wiring harnesses are securely connected and free from damage, as disconnected or damaged wiring can lead to system malfunctions. Finally, inspect the actuators and sensors for wear and tear, as damaged or worn components can significantly impact performance. By following this diagnostic approach, you can systematically identify and resolve the issues affecting your cruise control system, ensuring a smoother driving experience.

What Could Cause the Cruise Control to Malfunction in a Toyota Prius Plug-In?

When dealing with cruise control malfunctions in a Toyota Prius Plug-In, it's essential to recognize the common problems that may arise. A failed control module, sensor, or switch can often be the root cause, leading to a complete loss of functionality. Additionally, throttle actuation issues, particularly stemming from a faulty throttle position sensor, can cause the engine's computer to mismanage fuel delivery, which may result in noticeable black exhaust emissions. A blown fuse is another straightforward yet frequently overlooked issue that can disable the cruise control system entirely. If the cruise control operates intermittently, the problem may lie within the cruise control switch on the steering wheel, the spiral cable in the steering hub, or even the high-voltage ECU. Other potential culprits include faulty switches, speed sensor malfunctions, or issues with the engine control module (ECM). By understanding these common failure modes, DIY enthusiasts can effectively troubleshoot and address cruise control issues, ensuring a smoother driving experience.

Why is the Cruise Control Not Working in a Toyota Prius Plug-In?

When your Toyota Prius Plug-In's cruise control system fails, it’s crucial to address the issue promptly to ensure both your safety and the vehicle's performance. Common culprits include a malfunctioning control module, faulty sensors, or defective switches, all of which can disrupt the cruise control's operation. Additionally, throttle actuation problems may prevent the system from engaging properly, while a blown fuse can completely disable it. Ignoring these symptoms can lead to more severe complications, such as engine overcompensation due to a failing throttle position sensor, which may result in excessive fuel consumption and black exhaust emissions. Furthermore, the clock spring and brake light switch are vital components that can also affect cruise control functionality. Therefore, it’s essential to conduct a thorough inspection of these elements to identify the root cause of the malfunction. By addressing these issues promptly, you can avoid potential safety risks and costly repairs down the line.

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