Mercedes-Benz ML350 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz ML350 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
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25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 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 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.

Troubleshooting Cruise Control Issues in a Mercedes-Benz ML350

When troubleshooting cruise control issues in your Mercedes-Benz ML350, it's essential to adopt a systematic diagnostic approach. Start by checking the simplest components, such as the brake pedal switch, which is a common culprit for cruise control malfunctions. If the switch is defective, it can prevent the system from engaging. Next, inspect the vehicle's battery; a dead or weak battery can disrupt electrical systems, including cruise control. Following that, examine the ABS wheel speed sensor, as a failure here may trigger warning lights and affect cruise control functionality. Additionally, check for a blown fuse, which is often an easy fix that can restore operation. Don't overlook the brake lights and brake switch, as issues in these areas can also interfere with cruise control. Lastly, if the check engine light is illuminated or if there are any engine-related problems, these could be underlying factors affecting the cruise control system. By methodically assessing these components, you can effectively diagnose and potentially resolve the issue before seeking professional assistance.

What Could Cause the Cruise Control to Malfunction in a Mercedes-Benz ML350?

When diagnosing cruise control malfunctions in a Mercedes-Benz ML350, it's essential to consider several common problems that could disrupt the system's functionality. A failed control module is often at the forefront, as it serves as the brain of the cruise control system. Additionally, issues with sensors, such as a faulty ABS wheel speed sensor, can lead to incorrect readings that cause the cruise control to disengage unexpectedly. Another frequent culprit is the brake pedal switch; if this switch is defective, it may signal that the brakes are engaged even when they are not, resulting in the cruise control system shutting down. Furthermore, a dead battery can affect the electrical components necessary for cruise control operation. It's crucial to inspect these components thoroughly, as their proper functioning is vital for the cruise control system to operate smoothly and reliably. By understanding these potential failure modes, DIY enthusiasts can better troubleshoot and address issues with their vehicle's cruise control system.

Why is the Cruise Control Not Working in a Mercedes-Benz ML350?

When the cruise control in your Mercedes-Benz ML350 is not functioning, it is crucial to address the problem promptly, as neglecting it can lead to safety risks and further vehicle damage. Common culprits include a defective brake pedal switch, which can prevent the system from engaging, or a blown fuse that disrupts electrical connections. Additionally, issues with the throttle control system or the ABS may also contribute to the malfunction. If you notice the cruise control lever flashing without displaying the set speed, this could indicate a deeper system issue that requires immediate attention. Older models may suffer from broken vacuum lines, which can significantly impair cruise control functionality. Given the potential for these problems to affect your driving experience and safety, it is advisable to diagnose and repair the issue as soon as possible, either through DIY troubleshooting or by consulting a professional service team.

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