2008 Scion TC Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2008 Scion tC and How to Fix Them

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Reviewed by
Andrew Hajjar
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 2008 Scion tC 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 2008 Scion tC 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.

When the vehicle speed sensor fails or the wiring harness prevents signal transmission, the speedometer is the first thing that will stop functioning properly. This can be an intermittent issue where the speedometer only works occasionally, the speedometer may cease all function, or the speedometer may read erratically or incorrectly. Also, the traction control and anti lock brake warning lights specific to each vehicle may be illuminated, depending on the design of those systems. You may notice the vehicle hesitate to accelerate, cruise control will not function properly, and the vehicle may not shift properly through all of the gears.

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 troubleshoot the non-functioning cruise control in a 2008 Scion tC?

When troubleshooting the non-functioning cruise control in a 2008 Scion tC, it's essential to adopt a systematic diagnostic approach that begins with the simplest solutions before progressing to more complex issues. Start by checking the cruise control fuse located in the fuse box, as a blown fuse is a common and easily fixable problem. Next, inspect the cruise control buttons on the steering wheel to ensure they are operational, as malfunctioning buttons can prevent the system from engaging. Following this, verify the speed sensor, which is crucial for the cruise control to maintain a constant speed; a faulty sensor can disrupt the entire system. Utilizing an OBD-II scanner to check for error codes can provide valuable insights into any underlying issues affecting the cruise control. Additionally, ensure that the brake lights are functioning correctly, as a defective brake light switch can inhibit cruise control engagement. Lastly, if your vehicle's cruise control operates using vacuum pressure, inspect the vacuum lines for any leaks or damage that could be impacting performance. By methodically addressing these areas, you can effectively diagnose and potentially resolve the cruise control issue in your Scion tC.

What are the common problems that could cause the cruise control to stop working in a 2008 Scion tC?

When troubleshooting the cruise control system in a 2008 Scion tC, it's essential to consider several common problems that could be causing the malfunction. One of the primary issues is a faulty brake pedal switch, which is crucial for the cruise control's operation as it disengages the system when the brake is applied. If this switch is defective, the cruise control may not engage at all. Another potential culprit is a defective speed sensor; this component is responsible for relaying the vehicle's speed to the cruise control system, and if it fails, the system cannot maintain a constant speed. Additionally, a blown fuse can completely disable the cruise control, so checking the fuse box for any blown fuses is a straightforward first step. Vacuum leaks in the engine can also disrupt the necessary vacuum pressure for the cruise control to function properly, leading to erratic behavior or complete failure. Lastly, a malfunctioning cruise control module itself may be the root of the problem, preventing the system from engaging or maintaining speed. By systematically checking these components, you can effectively diagnose and potentially resolve the cruise control issues in your Scion tC.

How urgent is it to address the malfunctioning cruise control in a 2008 Scion tC?

When it comes to a malfunctioning cruise control system in your 2008 Scion tC, the urgency of addressing the issue cannot be overstated. A faulty cruise control can lead to unexpected acceleration or deceleration, creating a significant safety hazard on the road. This unpredictability not only puts you at risk but also endangers other drivers and pedestrians. Moreover, delaying repairs can exacerbate the problem, potentially leading to more extensive damage to the vehicle's components, which could result in costly repairs down the line. Therefore, it is crucial to prioritize the inspection and repair of your cruise control system by a qualified mechanic. Taking swift action not only ensures your safety but also helps maintain the overall integrity of your vehicle, making it a vital step for any responsible car owner.

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