2021 Subaru Legacy Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2021 Subaru Legacy and How to Fix Them

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Reviewed by
Bo Fader
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 2021 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 cruise control issue in a 2021 Subaru Legacy?

When troubleshooting a cruise control issue in a 2021 Subaru Legacy, it's essential to start with the simplest and most accessible checks before moving on to more complex diagnostics. Begin by inspecting the cruise control fuse; a blown fuse can easily disrupt the system's functionality. Next, verify the cruise control switch to ensure it is operating correctly, as a faulty switch can prevent the system from engaging. Following this, check the speed sensors, which are vital for the cruise control's operation, as they relay the vehicle's speed to the system. Utilizing a diagnostic scanner to scan for error codes can provide further insights into any underlying issues that may not be immediately visible. Lastly, ensure that the brake lights are functioning properly, as malfunctioning brake lights can inadvertently disable the cruise control system. By systematically addressing these areas, you can effectively diagnose and potentially resolve cruise control issues in your Subaru Legacy.

What are the common problems that could cause the cruise control to stop working in a 2021 Subaru Legacy?

When troubleshooting cruise control issues in a 2021 Subaru Legacy, it's essential to understand the common problems that may be at play. One frequent culprit is a faulty brake light switch, which can prevent the cruise control from engaging since the system is designed to disengage when the brake pedal is pressed. Additionally, issues with the speed sensor can disrupt the vehicle's ability to maintain a constant speed, leading to cruise control failure. Another potential problem is a blown fuse within the cruise control system; checking and replacing this fuse can often restore functionality. Furthermore, a malfunction in the throttle control system may hinder the cruise control's performance, making it difficult to maintain speed. Lastly, a defective cruise control module can also be the source of the problem, potentially requiring replacement to ensure proper operation. By systematically addressing these common issues, you can effectively troubleshoot and resolve cruise control problems in your Subaru Legacy.

How urgent is it to address the malfunctioning cruise control in my 2021 Subaru Legacy?

When it comes to the malfunctioning cruise control in your 2021 Subaru Legacy, the urgency of addressing the issue cannot be overstated. A faulty cruise control system can lead to unpredictable vehicle behavior, such as sudden acceleration or deceleration, which poses a significant safety risk while driving. Ignoring these symptoms may not only increase the likelihood of accidents but could also result in more extensive damage to your vehicle's systems, leading to costly repairs down the line. Therefore, it is crucial to have the cruise control inspected and repaired by a qualified mechanic or authorized service center as soon as possible. Taking prompt action not only ensures your safety on the road but also helps maintain the overall health of your vehicle, preventing further complications that could arise from neglecting the issue.

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