Mercedes-Benz SLK250 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz SLK250 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
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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 SLK250 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 SLK250 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 SLK250

When troubleshooting cruise control issues in your Mercedes-Benz SLK250, begin by inspecting the simplest components first. Start with the fuses, as a blown fuse can easily disrupt the cruise control system. Next, check the brake light switch; if it’s faulty, it may prevent the cruise control from engaging. After these initial checks, examine the control module and associated sensors for any signs of failure. If these components appear functional, move on to the throttle actuation system, ensuring that the throttle cable is intact and properly connected. Additionally, inspect the vacuum actuator and hoses for any damage or leaks, as these can significantly impact performance. Finally, verify the wheel speed sensor, as accurate readings are crucial for the cruise control to operate correctly. If the check engine light is illuminated, it’s essential to address any underlying engine issues, as they can also inhibit cruise control functionality. By following this methodical approach, you can effectively diagnose and resolve cruise control problems in your SLK250, ensuring a smoother driving experience.

What Could Cause the Cruise Control to Malfunction in a Mercedes-Benz SLK250?

When diagnosing cruise control malfunctions in a Mercedes-Benz SLK250, it's essential to consider several common problems that may be at play. A failed control module, sensor, or switch can disrupt the system's functionality, while throttle actuation issues may prevent the cruise control from engaging properly. Additionally, a defective brake pedal switch can inadvertently disable the cruise control, as it is designed to disengage when the brakes are applied. Other potential culprits include a dead battery, which can affect electronic systems, and a faulty ABS wheel speed sensor that may send incorrect signals to the cruise control system. In some cases, the toothed sensor ring on the left rear axle CV shaft may fail, leading to intermittent cruise control operation. Environmental factors, such as rainy conditions, can also trigger a "Cruise Control Inoperative" message due to unknown errors. Lastly, faults with the Brake Assist System (BAS) or Electronic Stability Program (ESP) can further complicate the situation. By understanding these common issues, DIYers can better diagnose and address the specific cause of their cruise control problems, ensuring a smoother driving experience.

Why is the Cruise Control Not Working in a Mercedes-Benz SLK250?

When the cruise control in your Mercedes-Benz SLK250 fails to operate, it’s crucial to address the issue promptly, as neglecting it can lead to safety risks and further vehicle complications. A defective brake pedal switch is often the culprit, as it can prevent the cruise control from engaging, leaving you without this essential driving aid. Additionally, a blown fuse may disrupt the electrical flow necessary for the system to function, while a faulty ABS wheel speed sensor can interfere with the vehicle's ability to maintain speed. Problems within the throttle control system can also hinder cruise control performance, making it vital to investigate these areas. In older models, a broken vacuum line could be the reason behind the malfunction. Ignoring these symptoms not only compromises your driving experience but could also lead to more significant repairs down the line. Therefore, it’s advisable to conduct a thorough check of these components or consult a professional to ensure your cruise control system is restored to optimal working condition.

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