Mercedes-Benz 400E Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz 400E 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 400E 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 400E 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 400E

When troubleshooting cruise control issues in your Mercedes-Benz 400E, start by checking the simplest components first. Begin with the cruise control switch and ensure it is functioning correctly; sometimes, a simple reset or cleaning can resolve the issue. Next, inspect the brake light switch, as a malfunction here can prevent the cruise control from engaging, even if the brake lights appear to work. If these initial checks do not yield results, examine the control module and associated wiring for any signs of damage or disconnection. Pay close attention to the spiral cable in the steering wheel, as a faulty sensor can disrupt the cruise control system. If the cruise control still fails to operate, investigate the throttle link rod for any looseness or disconnection, as this can directly affect functionality. Lastly, if you encounter warning messages on the instrument cluster or intermittent operation, it may be necessary to delve deeper into the electrical components and connectors. By following this structured approach, you can effectively diagnose and potentially resolve cruise control issues in your vehicle.

What Are the Common Problems Causing Cruise Control Issues in a Mercedes-Benz 400E?

When dealing with cruise control issues in a Mercedes-Benz 400E, it's important to understand the common problems that may arise. One of the primary culprits is a failed control module, which can disrupt the entire cruise control system's functionality. Additionally, sensor or switch malfunctions can lead to erratic behavior or complete failure of the cruise control feature. Another significant factor to consider is throttle actuation problems, which can prevent the system from maintaining the desired speed. By identifying these common issues, DIY enthusiasts can take the first steps toward diagnosing and potentially fixing their cruise control problems, ensuring a smoother and more reliable driving experience.

Why is the Cruise Control Not Working in a Mercedes-Benz 400E?

When the cruise control in your Mercedes-Benz 400E is not functioning, it’s crucial to address the issue without delay. Ignoring symptoms such as erratic behavior or complete failure can lead to more significant problems, including compromised safety features like ABS and stability control. A malfunctioning cruise control system can also indicate underlying issues with critical components such as the control module, sensors, or throttle actuation system. For instance, a faulty ABS sensor can not only disable cruise control but also affect your vehicle's braking capabilities. Additionally, mismatched tire sizes or uneven wear can cause intermittent operation, which may lead to unpredictable driving experiences. If the brake pedal switch is defective or a fuse is blown, these seemingly minor issues can escalate into major safety concerns. Therefore, it is essential to diagnose and repair these problems promptly, ensuring that your vehicle remains safe and reliable on the road. Taking the time to inspect these components can save you from costly repairs and enhance your driving experience.

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