2021 Mercedes-Benz GLC300 Cruise Control Isn't Working

Fixing Cruise Control Issues in the 2021 Mercedes-Benz GLC300

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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 2021 Mercedes-Benz GLC300 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 2021 Mercedes-Benz GLC300 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.

What steps should I take to diagnose the cruise control issue in my 2021 Mercedes-Benz GLC300?

To effectively diagnose the cruise control issue in your 2021 Mercedes-Benz GLC300, begin with a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Start by examining the cruise control fuse, as a blown fuse can easily disrupt functionality. Next, inspect the cruise control buttons on the steering wheel for any signs of damage or wear that could hinder their operation. Utilizing an OBD-II scanner is crucial for identifying any error codes that may provide insights into the underlying problem. Following this, check the speed sensors, as they are integral to the cruise control system's performance. It's also important to inspect the wiring connections for any loose or damaged wires that could be affecting the system. If these preliminary checks do not resolve the issue, testing the cruise control module will help determine if it is functioning correctly and sending the appropriate signals. Should you find yourself unable to pinpoint the problem after these steps, seeking assistance from a professional mechanic or an authorized Mercedes-Benz service center is advisable for a thorough diagnosis and resolution. This methodical approach not only saves time but also enhances the likelihood of identifying the root cause of the cruise control malfunction.

What are the common problems that could cause the cruise control to stop working in a 2021 Mercedes-Benz GLC300?

When the cruise control in your 2021 Mercedes-Benz GLC300 ceases to function, it can be frustrating, but understanding the common problems can guide you in troubleshooting the issue. One frequent culprit is a faulty speed sensor, which is essential for the cruise control system to accurately gauge your vehicle's speed. If this sensor malfunctions, the system may fail to engage or maintain the desired speed. Another common issue is related to the brake light switch; if this switch is defective, it can send incorrect signals to the cruise control system, causing it to disengage unexpectedly. Additionally, a malfunctioning throttle actuator can hinder the cruise control's ability to adjust the throttle position, further complicating its operation. In some cases, the cruise control module itself may be defective, necessitating repair or replacement to restore functionality. Lastly, electrical problems such as wiring issues or blown fuses can disrupt communication between the various components of the cruise control system. By identifying these potential problems, you can take the first steps toward diagnosing and fixing the cruise control system in your vehicle.

How urgent is it to address the malfunctioning cruise control in a 2021 Mercedes-Benz GLC300?

Addressing a malfunctioning cruise control in a 2021 Mercedes-Benz GLC300 is of utmost importance due to the significant safety risks and performance issues it can create. A malfunction can lead to unexpected changes in speed, increasing the likelihood of accidents and compromising the safety of both the driver and other road users. Furthermore, cruise control problems may signal deeper electronic system or sensor issues, which could affect other critical vehicle functions, leading to more extensive and costly repairs if left unaddressed. Additionally, ignoring these symptoms can result in decreased fuel efficiency and a diminished driving experience, ultimately impacting the vehicle's longevity. Therefore, it is crucial to prioritize the repair of cruise control malfunctions to ensure safe and efficient operation of your vehicle.

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