2018 Mercedes-Benz C300 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2018 Mercedes-Benz C300 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 Mercedes-Benz C300 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 C300 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 are the initial diagnostic steps to troubleshoot the non-functioning cruise control in a 2018 Mercedes-Benz C300?

When faced with a non-functioning cruise control in your 2018 Mercedes-Benz C300, start by checking the cruise control fuse located in the fuse box; a blown fuse can often be the simplest explanation for the malfunction. Next, ensure that the cruise control settings are correctly configured according to your vehicle's manual, as incorrect settings can prevent the system from engaging. Utilizing a diagnostic scanner to check for error codes can provide valuable insights into any underlying issues that may not be immediately apparent. Additionally, inspect the cruise control buttons on the steering wheel for any signs of damage or sticking, as these can hinder functionality. Finally, test the brake pedal switch, since a malfunction here can cause the cruise control to disengage unexpectedly. By systematically following these steps, you can effectively diagnose 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 2018 Mercedes-Benz C300?

When troubleshooting the cruise control system in a 2018 Mercedes-Benz C300, it's essential to understand the common problems that may lead to its failure. One of the primary culprits is a faulty brake light switch, which can prevent the cruise control from engaging since the system is designed to deactivate when the brake pedal is pressed. Additionally, issues with the speed sensor can disrupt the system's ability to maintain a steady speed, while a malfunctioning throttle actuator can hinder its capacity to regulate speed effectively. Electrical problems, such as blown fuses or wiring issues, can also contribute to cruise control failure. Lastly, software glitches within the vehicle's computer system may cause the cruise control to stop functioning properly. By identifying and addressing these potential issues, DIY enthusiasts can effectively diagnose and resolve cruise control problems in their Mercedes-Benz C300.

How urgent is it to address the malfunctioning cruise control in a 2018 Mercedes-Benz C300?

Addressing a malfunctioning cruise control system in a 2018 Mercedes-Benz C300 is of utmost importance due to the potential safety risks it poses. A malfunction can lead to unexpected acceleration or deceleration, which significantly increases the likelihood of accidents on the road. Promptly resolving this issue not only safeguards your safety but also prevents the risk of further complications that could arise from neglecting the problem. Delaying repairs may result in additional damage to the vehicle's components, leading to more extensive and costly repairs down the line. Moreover, a functioning cruise control system enhances the overall driving experience, providing convenience and comfort during long journeys. Therefore, it is crucial to prioritize the repair of the cruise control system to ensure both safety and optimal vehicle performance.

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