2009 Mercedes-Benz C300 Cruise Control Isn't Working

Fixing Cruise Control Issues in the 2009 Mercedes-Benz C300

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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 2009 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 2009 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 2009 Mercedes-Benz C300?

When faced with a non-functioning cruise control in a 2009 Mercedes-Benz C300, it's crucial to adopt a systematic diagnostic approach. Start by checking the cruise control fuse, as a blown fuse is a common and easily fixable issue that can halt the system's operation. Next, inspect the cruise control switch located on the steering wheel for any signs of damage or malfunction, as this component is vital for engaging the system. It's also important to verify that the brake lights are functioning correctly; a faulty brake light switch can inadvertently disable the cruise control. Additionally, examine the vehicle's speed sensors, as any issues here can directly impact the cruise control's ability to maintain speed. Finally, utilize an onboard diagnostic scanner to check for any error codes related to the cruise control system, which can provide valuable insights into more complex problems. By following these steps, you can effectively troubleshoot and potentially resolve the issue with your cruise control system.

What are the common problems that could cause the cruise control to stop working in a 2009 Mercedes-Benz C300?

When the cruise control in a 2009 Mercedes-Benz C300 ceases to function, several common problems may be at play. One of the primary culprits is a faulty brake light switch, which is crucial for the cruise control system as it disengages the system when the brake pedal is pressed. If this switch malfunctions, it can prevent the cruise control from engaging properly. Additionally, issues with the speed sensor can disrupt the system's ability to maintain a constant speed, leading to erratic behavior or complete failure. Another potential issue is vacuum leaks within the engine, which can interfere with the cruise control's operation, causing it to disengage unexpectedly. Furthermore, a defective cruise control module may also be responsible for the system's malfunction, as it is the central component that controls cruise functions. Lastly, electrical problems, such as blown fuses or wiring issues, can significantly impact the cruise control system's performance. By understanding these common problems, DIYers can effectively troubleshoot and address the issues plaguing their vehicle's cruise control system.

How urgent is it to address the non-functioning cruise control in a 2009 Mercedes-Benz C300?

When it comes to a non-functioning cruise control in a 2009 Mercedes-Benz C300, the urgency of addressing the issue cannot be overstated. While it may seem like a minor inconvenience, the cruise control system plays a crucial role in enhancing driving comfort and safety, particularly during long journeys. A malfunctioning cruise control could signal deeper electronic or sensor-related problems that might compromise other vehicle functions, leading to more significant issues down the line. Moreover, ignoring this symptom could pose safety risks, especially on highways where maintaining a consistent speed is essential for safe driving. For DIY enthusiasts, it’s advisable to conduct a thorough inspection of the cruise control system, checking for any blown fuses, faulty switches, or issues with the throttle control. By addressing the problem promptly, you not only ensure a safer driving experience but also potentially save on costly repairs in the future. Therefore, while it may not be an immediate emergency, taking action sooner rather than later is the best course of action for both safety and vehicle longevity.

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2009 Mercedes-Benz C300 Cruise Control Issues & Repairs