Smart Forfour Cruise Control Malfunction & Error Codes

Had the same cruise control failure on a Smart ForTwo (2018) with similar symptoms. After running diagnostics, the issue was traced to a faulty throttle body actuator and damaged wiring connections near the pedal assembly. The cruise control system relies heavily on proper communication between various car electronics components. In my case, the throttle body actuator had deteriorated connection pins, causing intermittent signal losses. The wire harness also showed signs of wear where it flexed near the pedal. The repair involved replacing the throttle body actuator assembly and rewiring the affected connection points. While not a critical safety issue that would prevent driving, it required specialized diagnostic equipment to properly identify the fault codes and verify the repair. The most common failure points in these systems typically involve either the actuator itself or the electrical connections. When these components fail, the car electronics system detects the inconsistency and disables the cruise control as a safety measure. Worth noting that leaving this unrepaired could potentially lead to other electrical issues down the line, as degraded connections tend to affect multiple systems over time.

Thanks for sharing your experience with the throttle body actuator replacement. The symptoms you described match mine exactly. Before I book a repair appointment, could you share how much the complete fix cost you? Also curious if youve had any other electrical issues pop up since the repair was done, especially wondering if the fuse box or other electronics stayed problem-free afterward.

Got my Smart ForTwo back from the shop recently where they fixed that cruise control malfunction. Pretty relieved it turned out to be just a loose cable connection at the steering wheel module, way simpler than the throttle body replacement I initially thought it might need. Total repair came to 95€, which covered diagnostics and fixing the faulty system. The mechanic mentioned these connection issues are fairly common in Smart models as the wiring can work loose over time. Since the repair, the cruise control works perfectly and no other electrical gremlins have shown up. No issues with the fuse box or any other electronics. The diagnostic scan showed everything else was running normally, so looks like it really was just that one connection causing all the trouble. Much cheaper fix than expected, and the car electronics are all functioning like they should now. Better to get these things checked early before they can cause more extensive problems.

Thanks to everyone who shared their experiences. Finally got my Smart fixed last week and wanted to close out this thread with my repair story. Took it to a specialist who immediately hooked up their diagnostic system. The car electronics showed multiple error codes pointing to the cruise control system. After a thorough check, they found a damaged throttle body actuator similar to what others mentioned. The repair cost ended up at 320€, including parts and labor. More than I hoped but less than I feared. They also discovered and fixed some corroded connections near the fuse box while they were in there, which might have caused problems later. The cruise control now works flawlessly. No warning lights or error messages since the fix. The mechanic mentioned these actuator failures are a known issue in these models, especially once they pass 100000km. Glad I got it sorted before it could affect other systems. The whole repair took about 3 hours, and they even cleaned up some other minor electrical connections while they were at it.