Mercedes-Benz E300 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz E300 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
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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 E300 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 E300 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 E300

When troubleshooting cruise control issues in your Mercedes-Benz E300, begin by checking the simplest components first. Start with the brake light switch, as a malfunctioning switch can prevent the cruise control from engaging, even if the brake lights appear to be functioning correctly. Next, inspect the cruise control switch on the steering wheel for any signs of wear or damage, as this can also lead to operational failures. If these components are in good condition, move on to the control module and sensors, which are critical for the cruise control system's functionality. A diagnostic scan tool can be invaluable at this stage, as it can reveal error codes related to the Electronic Throttle Actuator (ETA) and other systems. If the cruise control inoperative warning message is displayed, it indicates a deeper issue that may require professional assistance. By following this methodical approach, you can effectively identify and address the common causes of cruise control malfunctions in your E300, ensuring a smoother driving experience.

What Could Cause Cruise Control Malfunctions in a Mercedes-Benz E300?

When troubleshooting cruise control malfunctions in a Mercedes-Benz E300, it's crucial to consider several common problems that could be affecting the system. One of the primary culprits is a failed control module, which can disrupt the communication between various components. Additionally, sensor or switch failures, particularly those related to the throttle or brake pedal, can prevent the cruise control from functioning correctly. Throttle actuation issues may also arise, leading to erratic behavior or complete failure of the cruise control system. Furthermore, problems with the throttle control system or the anti-lock braking system (ABS) can contribute to these malfunctions. In older models, a broken vacuum line may be responsible for the cruise control not engaging properly. Symptoms such as black exhaust from the tailpipe can indicate a faulty throttle position sensor, which is another factor to investigate. By understanding these potential issues, DIYers can effectively diagnose and address cruise control problems in their Mercedes-Benz E300.

Why is the Cruise Control Not Working in a Mercedes-Benz E300?

When your Mercedes-Benz E300's cruise control fails, it’s crucial to understand the potential implications of this malfunction. Ignoring the issue can lead to not only inconvenience but also safety risks, as cruise control is often linked to other critical systems like ABS and stability control. A malfunctioning control module, sensor, or switch can disrupt the cruise control's operation, while a faulty ABS sensor may disable it entirely, compromising your vehicle's safety features. Additionally, mismatched tire sizes or uneven tire wear can cause erratic cruise control behavior, which could lead to dangerous driving conditions. A defective brake pedal switch or a blown fuse can also be culprits, and these issues should not be overlooked. Addressing these problems promptly is essential to ensure your vehicle operates safely and efficiently, preventing further damage and maintaining your driving comfort.

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