Mercedes-Benz C320 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz C320 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 C320 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 C320 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 C320

When troubleshooting cruise control issues in your Mercedes-Benz C320, begin with the simplest potential problems before delving into more complex diagnostics. Start by checking the brake light switch, as a faulty switch can prevent the cruise control from engaging. Next, inspect the fuse box for any blown fuses related to the cruise control system, as this is a common and easily fixable issue. If these initial checks do not resolve the problem, examine the cruise control switch and the throttle actuation system for any signs of malfunction. Additionally, pay attention to any warning messages on the instrument cluster, as these can provide clues about the underlying issue. If the problem persists after these checks, it may be necessary to investigate the control module or the cruise control ECU/Amplifier, which may require professional diagnostic tools. By following this structured approach, you can systematically identify and address the root cause of the cruise control malfunction in your vehicle.

What Are the Common Problems Causing Cruise Control Issues in a Mercedes-Benz C320?

When diagnosing cruise control issues in a Mercedes-Benz C320, it's essential to understand the common problems that may arise. One of the primary culprits is a failed control module, sensor, or switch, which can disrupt the entire cruise control system. Additionally, throttle actuation problems can prevent the system from functioning correctly. A frequently overlooked issue is a faulty ABS sensor; if any of the ABS wheel speed sensors fail, it can not only disable cruise control but also impact other critical systems like ABS and stability control. Another potential cause is a blown fuse, which can occur due to a short circuit, leading to a complete failure of the cruise control system. Furthermore, a malfunctioning brake pedal switch can interfere with cruise control functionality, as this switch is responsible for activating the brake lights. Lastly, issues with the engine or transmission can also lead to the cruise control turning off unexpectedly, particularly in newer models. By identifying these common problems, DIY enthusiasts can better troubleshoot and resolve cruise control issues in their Mercedes-Benz C320.

Why is the Cruise Control Not Working in a Mercedes-Benz C320?

When the cruise control in your Mercedes-Benz C320 malfunctions, it’s crucial to address the issue promptly to avoid potential safety risks and further damage to your vehicle. Ignoring symptoms such as an error message indicating that the cruise control is inoperative or the presence of warning lights like ETS and ABS can lead to more significant problems down the line. For instance, a faulty brake pedal switch or a malfunctioning ABS wheel speed sensor not only affects cruise control functionality but can also compromise your vehicle's overall braking system. Additionally, if the cruise control system is disabled due to ESP errors, it may indicate deeper issues that require immediate attention. Regularly checking fuses and ensuring that brake lights are operational can help you catch these problems early. By taking swift action to diagnose and repair cruise control issues, you not only enhance your driving experience but also ensure the safety of yourself and others on the road.

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