Mercedes-Benz SL320 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Mercedes-Benz SL320 and How to Fix Them

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Reviewed by
Andrew Hajjar
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 SL320 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 SL320 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 SL320

When troubleshooting cruise control issues in your Mercedes-Benz SL320, begin by checking for any warning messages on the instrument cluster, as these can provide immediate insight into the problem. Next, inspect the cruise control module connector and ensure that the cruise control switch and brake switch are functioning correctly, as these components are often the source of the issue. Pay attention to blown fuses or malfunctioning brake lights, which can disrupt the cruise control system. If these initial checks do not resolve the problem, examine the vacuum actuator and associated hoses, as leaks or blockages here can prevent the system from operating. While DIY diagnostics can be effective, remember that some issues may require professional expertise, especially if you encounter persistent problems or if the system involves complex components. Always prioritize safety and consider consulting a qualified technician for a thorough evaluation if needed.

What Could Cause the Cruise Control to Malfunction in a Mercedes-Benz SL320?

When dealing with cruise control malfunctions in a Mercedes-Benz SL320, it's crucial to understand the various common problems that could be at play. One of the primary culprits is a failed control module, which can disrupt the entire cruise control system. Additionally, issues with sensors or switches, particularly the brake pedal switch, can prevent the cruise control from engaging properly. The throttle actuation system is another area to investigate, as any malfunction here can directly impact cruise control functionality. Furthermore, a faulty ABS sensor can disable the cruise control feature, as the system relies on accurate wheel speed readings to function correctly. Other potential issues include a blown fuse, defective wiring, or even problems with older vacuum-operated systems. To effectively diagnose the problem, using a diagnostic scanner to retrieve fault codes is recommended, along with a thorough visual inspection of the cruise control components. Testing the cruise control switch and module for proper operation can also help pinpoint the issue, allowing for targeted repairs that can restore functionality. By understanding these common problems, DIY enthusiasts can take informed steps toward troubleshooting and resolving cruise control issues in their Mercedes-Benz SL320.

Why is the Cruise Control Not Working in a Mercedes-Benz SL320?

When the cruise control in your Mercedes-Benz SL320 is not functioning, it is crucial to address the issue without delay. Ignoring symptoms such as unresponsive controls or sudden disengagement can lead to more significant problems, including potential safety hazards while driving. For instance, a malfunctioning ABS sensor can not only disable your cruise control but also compromise your vehicle's stability and braking systems, increasing the risk of accidents. Additionally, a defective brake pedal switch or faulty brake lights can disrupt the cruise control operation, making it essential to ensure these components are in good working order. By taking the time to inspect these systems early on, you can prevent further damage and ensure a safer driving experience. If basic checks do not resolve the issue, seeking assistance from a qualified mechanic is advisable to avoid escalating the problem and to maintain the integrity of your vehicle's performance.

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