2020 Mercedes-Benz SL450 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2020 Mercedes-Benz SL450 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 2020 Mercedes-Benz SL450 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 2020 Mercedes-Benz SL450 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 2020 Mercedes-Benz SL450?

To diagnose the cruise control issue in your 2020 Mercedes-Benz SL450, begin with the simplest checks before moving on to more complex diagnostics. Start by inspecting the cruise control fuse; a blown fuse can easily disrupt the system's functionality. Next, examine the cruise control buttons on the steering wheel to ensure they are operational, as faulty buttons can lead to malfunctions. If these initial checks do not reveal the problem, utilize an OBD-II scanner to identify any error codes that may indicate specific issues within the cruise control system. Pay close attention to the speed sensors, as they are essential for the cruise control's performance; ensure they are functioning correctly. Additionally, inspect the wiring connections associated with the cruise control system for any signs of damage or loose connections that could be causing the problem. Finally, test the cruise control module itself, as a malfunction here can also lead to issues. If these steps do not resolve the problem, it may be time to consult a professional mechanic or an authorized Mercedes-Benz service center for a comprehensive diagnosis and repair. By following this structured approach, you can effectively troubleshoot and potentially resolve the cruise control issue in your vehicle.

What are the common problems that could cause the cruise control to stop working in a 2020 Mercedes-Benz SL450?

When the cruise control in your 2020 Mercedes-Benz SL450 ceases to function, it can be frustrating, but understanding the common problems can help you diagnose the issue. One frequent culprit is a faulty speed sensor, which is crucial for the system to accurately gauge your vehicle's speed. If this sensor is malfunctioning, the cruise control may fail to engage or maintain the desired speed. Another potential issue is the brake light switch; if this switch is defective, it can inadvertently signal the cruise control to disengage whenever the brakes are applied. Additionally, problems with the throttle actuator can hinder the system's ability to maintain speed, as it directly controls the engine's throttle. Electrical issues, such as blown fuses or wiring problems, can also disrupt the cruise control's operation, so checking these components is essential. Lastly, vacuum leaks within the cruise control system can lead to functionality problems, making it difficult for the system to engage or hold speed. By systematically checking these areas, you can identify the root cause of the cruise control failure and take the necessary steps to restore its functionality.

How urgent is it to address the malfunctioning cruise control in my 2020 Mercedes-Benz SL450?

Addressing the malfunctioning cruise control in your 2020 Mercedes-Benz SL450 is of utmost importance due to the potential safety risks it poses. A faulty cruise control system can lead to unexpected acceleration or deceleration, increasing the likelihood of accidents on the road. Moreover, neglecting this issue may result in more extensive damage to the vehicle's electronic systems, which could lead to costly repairs down the line. Beyond safety and financial implications, a properly functioning cruise control system significantly enhances your driving experience by providing comfort and efficiency during long trips. Therefore, it is crucial to prioritize the repair of your cruise control system to ensure your safety, protect your investment, and enjoy the full benefits of your vehicle's features.

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