Mercedes-Benz GLS550 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz GLS550 and How to Fix Them

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
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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 GLS550 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 GLS550 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 GLS550

When troubleshooting cruise control issues in your Mercedes-Benz GLS550, begin with the simplest potential problems before delving into more complex diagnostics. Start by inspecting the brake light switch, as a malfunction here can cause the cruise control to disengage unexpectedly. Ensure that the brake lights are functioning correctly; if they are not, replacing the brake light switch may resolve the issue. Next, check the cruise control control switch for any signs of wear or malfunction, as this can also impact the system's performance. If these components are functioning properly, consider examining the vehicle's sensors, as sensor failures are a common culprit in cruise control malfunctions. If necessary, you may need to replace specific modules that control the cruise control system. Lastly, keep an eye on any engine-related issues, such as a check engine light, which can interfere with cruise control functionality. By following this diagnostic approach, you can systematically identify and address the root cause of the cruise control problems in your GLS550.

What Are the Common Problems Causing Cruise Control Issues in a Mercedes-Benz GLS550?

When dealing with cruise control issues in a Mercedes-Benz GLS550, it's essential to understand the common problems that may arise. One frequent culprit is a failed control module, sensor, or switch, which can disrupt the cruise control's functionality. Additionally, throttle actuation problems can significantly impact how the cruise control operates, leading to erratic behavior or complete failure. Owners should also be aware of potential issues with the adaptive cruise control system, which may become unresponsive or fail to detect vehicles ahead, compromising safety and convenience. Other factors to consider include the brake pedal switch, which can prevent cruise control from engaging if malfunctioning, as well as a dead battery or faulty ABS wheel speed sensor, both of which can hinder the system's performance. By identifying these common problems, DIY enthusiasts can take the first steps toward troubleshooting and repairing their vehicle's cruise control system effectively.

Why is the Cruise Control Not Working in a Mercedes-Benz GLS550?

When the cruise control in your Mercedes-Benz GLS550 is malfunctioning, it is crucial to address the issue promptly, as neglecting it can lead to safety risks and further complications. A faulty ABS sensor is a common culprit, as it can disable not only the cruise control but also essential systems like ABS and stability control, which are vital for safe driving. Additionally, a blown fuse or a defective brake pedal switch can disrupt the cruise control's functionality, making it imperative to check these components. If the throttle control system is compromised, or if there are issues with the ABS, the cruise control may also fail to operate correctly. In older models, a broken vacuum line could be the source of the problem. It is advisable to have the vehicle's diagnostic codes read using the MB diagnostic system to pinpoint specific faults, as some cruise control issues may be linked to ESP problems. Furthermore, ensure that the cruise control is correctly selected; if the LIM indicator lamp is illuminated, it may prevent the system from engaging. By addressing these issues swiftly, you can maintain the safety and performance of your vehicle, avoiding potential hazards on the road.

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