2009 Mercedes-Benz ML350 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2009 Mercedes-Benz ML350 and How to Fix Them

Find Repair Location
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 ML350 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 ML350 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.

What are the initial diagnostic steps to troubleshoot the non-functional cruise control in a 2009 Mercedes-Benz ML350?

When troubleshooting the non-functional cruise control in a 2009 Mercedes-Benz ML350, it's crucial to follow a structured diagnostic approach that prioritizes simpler checks before delving into more complex diagnostics. Start by inspecting the cruise control fuse in the fuse box, as a blown fuse can easily disrupt the system's functionality. Next, assess the cruise control switch on the steering wheel to ensure it is operational and free from damage. The brake pedal switch is another key component; a malfunctioning switch can prevent the cruise control from engaging, so it should be thoroughly examined. Utilizing a diagnostic scanner to retrieve any error codes from the vehicle's onboard computer can also provide critical information regarding potential issues. Finally, confirm that the vehicle speed sensor is working correctly, as it plays an essential role in the cruise control system's operation. By systematically addressing these areas, you can effectively identify and resolve the underlying causes of the cruise control malfunction in your vehicle.

What are the common problems that could cause the cruise control to stop working in a 2009 Mercedes-Benz ML350?

When troubleshooting cruise control issues in a 2009 Mercedes-Benz ML350, it's essential to consider several common problems that could be at play. One of the primary culprits is a faulty brake light switch, which can prevent the cruise control from engaging if it fails to detect when the brake pedal is pressed. Additionally, issues with the speed sensor can disrupt the system's ability to maintain a constant speed, leading to cruise control failure. Another potential problem is vacuum leaks within the system, which can hinder the engine's capacity to sustain a steady speed. Furthermore, a defective cruise control module may also be responsible for the malfunction, as it plays a critical role in the system's operation. Lastly, electrical problems, such as blown fuses or wiring issues, can significantly impact the functionality of the cruise control. By systematically addressing these common issues, you can effectively troubleshoot and potentially resolve the cruise control problems in your vehicle.

How urgent is it to address the non-functioning cruise control in a 2009 Mercedes-Benz ML350?

When it comes to the non-functioning cruise control in a 2009 Mercedes-Benz ML350, understanding the urgency of the situation is crucial for any DIY enthusiast. While the immediate safety risks may not be as pronounced as with other critical vehicle systems, neglecting this issue can lead to a range of inconveniences and potential complications. A malfunctioning cruise control can diminish the driving experience, particularly on long trips where maintaining a constant speed is beneficial for reducing fatigue and improving fuel efficiency. Moreover, if left unaddressed, the underlying causes of the malfunction could escalate, potentially affecting other vehicle systems and leading to more significant repairs down the line. Therefore, while it may not be an emergency, it is advisable to prioritize an inspection and repair of the cruise control system. This proactive approach not only ensures the vehicle's performance remains optimal but also helps maintain its overall value, making it a wise decision for any conscientious vehicle owner.

You’ve got options with RepairPal

Whether you need a more accurate auto repair estimate or help finding a reputable shop in your area, we’ve got you covered.