Mercedes-Benz SL550 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz SL550 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 SL550 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 SL550 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 SL550

When troubleshooting cruise control issues in your Mercedes-Benz SL550, it's essential to adopt a systematic diagnostic approach. Begin by checking the cruise control fuse, as a blown fuse is a straightforward fix that can often resolve the problem. Next, inspect the cruise control buttons on the steering wheel to ensure they are functioning correctly; sometimes, a simple button malfunction can prevent engagement. Following this, verify the speed sensors, which are crucial for maintaining a constant speed; any malfunction here can disrupt the system's operation. Additionally, examine the wiring connections associated with the cruise control system, as loose or damaged wires can lead to significant issues. If these initial checks do not reveal the problem, use a diagnostic scanner to scan for error codes that may indicate specific faults. It's also wise to inspect the vacuum lines for any leaks, as these can adversely affect the cruise control's performance. If, after all these steps, the issue persists, consider seeking professional assistance to ensure a thorough diagnosis and repair. By following this structured approach, you can effectively identify and potentially resolve cruise control issues in your SL550.

What Could Cause Cruise Control Issues in a Mercedes-Benz SL550?

When troubleshooting cruise control issues in a Mercedes-Benz SL550, it's essential to consider several common problems that could be at fault. A failed control module, sensor, or switch can disrupt the communication necessary for cruise control to function properly. Additionally, throttle actuation problems, often stemming from a malfunctioning throttle position sensor or control system, can hinder the system's performance. Another frequent culprit is a defective brake pedal switch, which can prevent the cruise control from engaging or disengaging as intended. It's also worth checking the battery; a dead battery can lead to various electrical issues, including those affecting cruise control. Furthermore, a faulty ABS wheel speed sensor can not only impact cruise control but may also trigger warning lights for the ESP and ABS systems. In older models, a broken vacuum line can disrupt the cruise control mechanism, while a bad spiral cable in the steering wheel can impede communication between the cruise control switch and the system. Lastly, any underlying electrical issues, such as damaged connectors or wiring, can also contribute to cruise control malfunctions. By systematically diagnosing these potential problems, you can effectively address and resolve cruise control issues in your SL550.

Why is the Cruise Control Not Working in a Mercedes-Benz SL550?

When your Mercedes-Benz SL550's cruise control fails, it’s crucial to understand the underlying issues that could be at play. A defective brake pedal switch is often the primary suspect, as it can prevent the system from engaging properly. Additionally, a blown fuse may disrupt the electrical flow necessary for cruise control functionality. If you notice warning lights such as ESP or ABS on your dashboard, this could indicate a faulty ABS wheel speed sensor, which directly impacts cruise control performance. Furthermore, problems with the throttle control system or even a broken vacuum line in older models can lead to similar malfunctions. While some of these issues may seem minor, neglecting them can pose safety risks and potentially lead to more significant damage to your vehicle. Therefore, if you encounter any symptoms of cruise control failure, it’s advisable to address them promptly, either through DIY troubleshooting or by consulting a qualified service technician for a thorough inspection and repair.

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Mercedes-Benz SL550 Cruise Control Issues & Repairs