2018 Subaru Legacy Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2018 Subaru Legacy 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 2018 Subaru Legacy 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.

What are the initial diagnostic steps to troubleshoot the non-functioning cruise control in a 2018 Subaru Legacy?

When faced with a non-functioning cruise control in your 2018 Subaru Legacy, start by checking the cruise control fuse, as a blown fuse can often be the simplest explanation for the malfunction. Next, verify that the cruise control settings are correctly configured; sometimes, the system may not engage due to incorrect settings. Utilizing a diagnostic scanner to check for error codes can provide insights into any underlying issues that may not be immediately visible. Additionally, inspect the cruise control buttons on the steering wheel for any signs of damage or sticking, as these can prevent proper operation. Finally, test the cruise control engagement at various speeds to determine if the system activates and maintains speed as expected. By systematically following these steps, you can effectively diagnose and potentially resolve the cruise control issue in your Subaru Legacy.

What are the common problems that could cause the cruise control to stop working in a 2018 Subaru Legacy?

When troubleshooting cruise control issues in a 2018 Subaru Legacy, it's essential to consider several common problems that could be at play. One of the first areas to check is the brake light switch, as a faulty switch can prevent the cruise control from engaging, since it is designed to deactivate when the brake pedal is pressed. Additionally, the speed sensor plays a crucial role in maintaining a constant speed; if it malfunctions, the cruise control may fail to operate correctly. Another potential culprit is a blown fuse within the cruise control system, which can completely disable its functionality. Throttle control malfunctions can also hinder the system's ability to maintain speed, so inspecting this component is advisable. Lastly, vacuum leaks in the engine can disrupt the necessary vacuum pressure for the cruise control to function smoothly. By systematically examining these areas, DIYers can identify and address the root cause of their cruise control issues effectively.

How urgent is the repair of the non-functioning cruise control in a 2018 Subaru Legacy?

When considering the urgency of repairing a non-functioning cruise control in a 2018 Subaru Legacy, it is essential to recognize the potential safety risks involved. A malfunctioning cruise control system can lead to unpredictable vehicle behavior, especially during long drives or in heavy traffic, increasing the likelihood of accidents. Additionally, for those who rely on cruise control for comfort during extended trips, the absence of this feature can result in driver fatigue and discomfort, making timely repairs even more critical. Furthermore, neglecting to address this issue can adversely affect the vehicle's resale value; prospective buyers often shy away from cars with unresolved mechanical problems. To make an informed decision about the urgency of repair, it is advisable to have the cruise control system diagnosed by a qualified mechanic. This assessment will provide clarity on the severity of the malfunction and help prioritize repairs, ensuring a safer and more enjoyable driving experience.

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2018 Subaru Legacy Cruise Control Issues & Repairs