Mercedes-Benz C400 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz C400 and How to Fix Them

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Reviewed by
Devin Cabugcal
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 C400 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 C400 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.

Troubleshooting Cruise Control Issues in a Mercedes-Benz C400

When troubleshooting cruise control issues in a Mercedes-Benz C400, it's essential to adopt a systematic diagnostic approach that begins with the simplest potential problems before moving on to more complex ones. Start by checking the cruise control button on the steering wheel for any dirt or damage that might prevent it from functioning properly. If the button appears to be in good condition, inspect the vehicle's fuses, as a blown fuse can easily disrupt the cruise control system. Next, examine the electrical connections and wiring for any signs of wear or damage, as these can lead to malfunctions. If these initial checks do not resolve the issue, consider the condition of the ABS wheel speed sensors, as a failure in any of these sensors can disable the cruise control along with other critical systems. Additionally, assess the throttle actuation and control module, as problems in these areas can also contribute to cruise control failures. By following this methodical approach, you can effectively identify and address the root cause of the cruise control malfunction in your Mercedes-Benz C400.

What Could Cause Cruise Control Issues in a Mercedes-Benz C400?

When troubleshooting cruise control issues in a Mercedes-Benz C400, it's crucial to recognize the various common problems that may be at play. A failed control module, sensor, or switch can often disrupt the functionality of the cruise control system, leading to frustrating driving experiences. Additionally, throttle actuation problems, particularly those stemming from a faulty throttle position sensor, can cause the engine's computer to mismanage fuel delivery, which may result in noticeable black exhaust emissions. Other factors to consider include a dead battery or a malfunctioning ABS wheel speed sensor, both of which can trigger warning lights for the Electronic Stability Program (ESP) and Anti-lock Braking System (ABS). Furthermore, a blown fuse or a defective brake pedal switch are frequent culprits that can affect cruise control performance. Given the interconnected nature of the cruise control system with other vehicle systems, diagnosing and repairing these issues can be complex. Therefore, while DIY enthusiasts may attempt to identify these problems, seeking expert advice can often lead to more effective and cost-efficient solutions.

Why is the Cruise Control Not Working in a Mercedes-Benz C400?

When the cruise control in your Mercedes-Benz C400 fails, it’s crucial to understand the potential implications of this malfunction. Ignoring the symptoms can lead to safety risks, especially if the issue stems from a faulty ABS sensor, which is vital for maintaining vehicle stability. A malfunctioning cruise control system not only diminishes driving comfort but can also indicate deeper problems, such as a failed control module or throttle actuation issues. These components are integral to the vehicle's performance, and neglecting them could result in more significant damage or costly repairs down the line. Therefore, if you notice your cruise control is not functioning properly, it’s essential to diagnose the specific cause promptly. This proactive approach not only ensures your safety on the road but also helps maintain the overall health of your vehicle.

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