Smart Fortwo Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your Smart Fortwo 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 Smart Fortwo 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 Smart Fortwo 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.

The cruise control switch can cause complete failure of the cruise control feature, but in a lucky scenario only partial functionality will be lost. This means that the cruise control may come on, but that it will not increase in speed automatically, or the cancel button does not work leading the driver to cancel cruise control with the foot brake. In some vehicles, the cruise control light may illuminate, or a warning message may be displayed due to lack of functionality.

Troubleshooting Cruise Control Issues in a Smart Fortwo

When troubleshooting cruise control issues in your Smart Fortwo, start with the simplest potential problems. Begin by checking the fuses associated with the cruise control system, as a blown fuse can easily disrupt functionality. Next, inspect the brake pedal and throttle body; both components are critical for the cruise control to operate correctly. Ensure that the speed sensor is functioning, as it provides essential data for the system. Don’t overlook the brake lights; if they are not working, the cruise control may not engage. Additionally, examine the brake pedal switch, as a defect here can prevent the system from activating. If these components check out, turn your attention to the throttle control system and the ABS system, as issues in these areas can also affect cruise control performance. Finally, inspect the electrical wiring for any signs of damage or poor connections, especially if modifications have been made. By following this diagnostic approach, you can effectively identify and resolve the root cause of cruise control issues in your Smart Fortwo.

What Could Cause the Cruise Control to Malfunction in a Smart Fortwo?

When dealing with cruise control malfunctions in a Smart Fortwo, it's essential to recognize the common problems that may arise. One of the primary culprits is a failed control module, which can disrupt the entire cruise control system. Additionally, issues with sensors, particularly the throttle position sensor, can lead to erratic behavior; a malfunctioning sensor may cause the engine to receive incorrect fuel levels, resulting in noticeable black exhaust. Other frequent issues include blown fuses and problems with the brake pedal position sensor, which can prevent the cruise control from engaging. Throttle body malfunctions and PRNDL/shifter position switch failures are also known to contribute to these problems. Furthermore, it's important to check for door closure detection issues, as the cruise control may deactivate if the system detects that a door or trunk is ajar. By understanding these potential failure modes, DIYers can systematically troubleshoot and address the underlying causes of cruise control malfunctions in their Smart Fortwo.

Why is the Cruise Control Not Working in a Smart Fortwo?

When the cruise control in your Smart Fortwo is not functioning, it’s crucial to address the issue without delay. Ignoring symptoms such as erratic behavior or complete failure can lead to safety risks, particularly if you rely on this feature for long drives. A faulty cruise control switch, for instance, can prevent the system from engaging, while issues with the speed sensor can disrupt its operation, leaving you without the convenience of maintaining a steady speed. Additionally, a malfunctioning brake light switch may cause the cruise control to disengage unexpectedly, which can be dangerous in certain driving conditions. If the throttle actuator is compromised, it may struggle to maintain speed, leading to unpredictable acceleration. Furthermore, electrical problems such as wiring issues or blown fuses can exacerbate the situation, potentially resulting in more significant damage if left unchecked. Therefore, it’s advisable to conduct a thorough inspection or consult a qualified mechanic to diagnose the specific cause of the cruise control failure, ensuring your vehicle remains safe and reliable on the road.

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