2018 Mercedes-Benz CLS550 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2018 Mercedes-Benz CLS550 and How to Fix Them

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Reviewed by
Aisha
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
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25% chance it's the
Control Module
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25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 2018 Mercedes-Benz CLS550 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 2018 Mercedes-Benz CLS550 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.

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.

A faulty cruise control module will simply result in deactivation of cruise control settings. This is because a detected error in the cruise control system could lead to hazardous driving conditions, so the module will be disabled, and the cruise control system warning light will be displayed. This will be a different message depending on make and model, and a warning light or message may be displayed on the driver instrument cluster.

What steps should I take to diagnose the non-functioning cruise control in my 2018 Mercedes-Benz CLS550?

To effectively diagnose the non-functioning cruise control in your 2018 Mercedes-Benz CLS550, begin with a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Start by inspecting the cruise control fuse located in the fuse box, as a blown fuse is a common and easily rectifiable issue. Next, examine the cruise control buttons on your steering wheel for any signs of damage or sticking, as these can hinder the system's operation. Following this, verify the functionality of the speed sensors, as they play a crucial role in the cruise control system's performance. Utilizing a diagnostic scanner to check for error codes can provide valuable insights into any underlying issues. Additionally, ensure that the brake and clutch switches are operating correctly, as faulty switches can prevent the cruise control from engaging. Finally, inspect the wiring and connections associated with the cruise control system for any damage or corrosion, as these can lead to failures. By methodically following these steps, you can identify the root cause of the cruise control malfunction and take appropriate action to restore its functionality.

What are the common problems that could cause the cruise control to stop working in a 2018 Mercedes-Benz CLS550?

When the cruise control in your 2018 Mercedes-Benz CLS550 ceases to function, it can be frustrating, but understanding the common problems can help you troubleshoot effectively. One of the primary culprits is a faulty speed sensor, which is crucial for the system to accurately gauge your vehicle's speed. If this sensor malfunctions, the cruise control may fail to engage or maintain the desired speed. Another frequent issue arises from the brake light switch; if this switch is defective, it may not signal the cruise control system to disengage when the brake pedal is pressed, leading to operational failures. Additionally, a malfunctioning throttle actuator can disrupt the system's ability to maintain a constant speed, as it directly controls the engine's throttle opening. The cruise control module itself can also be a source of trouble; if this component is defective, it can prevent the cruise control from functioning correctly. Lastly, electrical problems such as wiring issues or blown fuses can significantly impact the cruise control system. By systematically checking these components, you can identify and address the underlying issues, potentially restoring your cruise control functionality without the need for professional assistance.

How urgent is it to repair the non-functioning cruise control in a 2018 Mercedes-Benz CLS550?

Repairing the non-functioning cruise control in a 2018 Mercedes-Benz CLS550 should be treated as an urgent matter due to its significant impact on both safety and driving comfort. A malfunctioning cruise control system can lead to increased driver fatigue, as maintaining a consistent speed becomes a manual task, particularly on long journeys. This added strain can distract the driver, heightening the risk of accidents. Furthermore, the absence of this feature diminishes the overall driving experience, making trips less enjoyable and more tiresome. Additionally, neglecting this repair could adversely affect the vehicle's resale value; potential buyers often look for well-maintained features, and a non-functioning cruise control system may raise concerns about the car's overall condition. Therefore, addressing this issue promptly not only enhances safety and comfort but also helps preserve the vehicle's value, making it a priority for any CLS550 owner.

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2018 Mercedes-Benz CLS550 Cruise Control Issues & Repairs