2009 Mercedes-Benz R350 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2009 Mercedes-Benz R350 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
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 R350 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 R350 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 R350?

When troubleshooting the non-functioning cruise control in your 2009 Mercedes-Benz R350, start with the simplest checks to avoid unnecessary complications. Begin by inspecting the cruise control fuse; a blown or damaged fuse can easily disrupt the system's operation. Next, examine the cruise control switch located on the steering wheel to confirm it is working correctly, as a malfunctioning switch can prevent activation. It's also crucial to check the brake lights, since a faulty brake light switch can inadvertently disable the cruise control. Additionally, ensure that the vehicle speed sensor is functioning properly, as it must relay accurate speed information to the cruise control module. Finally, utilize an onboard diagnostic scanner to check for any error codes that may indicate specific issues within the cruise control system. By systematically addressing these areas, you can effectively narrow down the potential causes of the cruise control malfunction and take appropriate action to resolve the issue.

What are the common problems that could cause the cruise control to stop working in a 2009 Mercedes-Benz R350?

When the cruise control in your 2009 Mercedes-Benz R350 ceases to function, it can be frustrating, but understanding the common problems can help you diagnose the issue effectively. 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 may prevent the cruise control from engaging at all. Another potential issue could be related to the speed sensor; if this component is not accurately relaying speed information, the cruise control may struggle to maintain a constant speed. Additionally, vacuum leaks in the engine can disrupt the system's ability to hold speed, leading to inconsistent performance. A defective cruise control module can also be a significant factor, as it is responsible for controlling the cruise system's operations. Lastly, electrical problems, such as blown fuses or damaged wiring, can interfere with the cruise control's functionality. By systematically checking these areas, you can effectively troubleshoot and potentially resolve the cruise control issues in your vehicle.

How urgent is it to address the non-functioning cruise control in a 2009 Mercedes-Benz R350?

Addressing a non-functioning cruise control in a 2009 Mercedes-Benz R350 is crucial for both safety and vehicle performance. While it may not seem like an immediate emergency, neglecting this issue can lead to more significant problems down the line. The cruise control system is designed to enhance driving comfort and efficiency, especially during long trips, and its failure could indicate underlying electronic or sensor issues that might affect other vehicle functions. Moreover, relying on manual speed control can increase driver fatigue and the risk of speed-related accidents, particularly on highways where cruise control is typically utilized. Therefore, it is advisable to have the system inspected and repaired by a qualified mechanic as soon as possible to ensure the vehicle remains safe and reliable on the road. Prompt attention to this issue not only preserves the functionality of the cruise control but also safeguards the overall health of the vehicle, preventing potential safety hazards and costly repairs in the future.

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