Smart Forfour EV Steering Sensor Causes Control Issues

Had almost the exact same issue with my Smart ForTwo EV 2019 last summer. Having worked on basic car maintenance, I have some experience with electric vehicle systems, though sensor issues were new territory for me. The symptoms matched yours perfectly, heavy steering and stability control acting up. The steering column was fine mechanically, but the angle sensor was causing problems with the power assist system. Took it to a workshop specializing in EV repairs. They ran diagnostics which pointed to incorrect coding of the steering angle sensor. The issue stemmed from a calibration problem rather than physical sensor damage. They had to recalibrate the sensor and run a wheel alignment check to ensure everything was properly synchronized. Total repair cost was 195€ and took about 2 hours. The steering went back to normal immediately, and the stability control warnings disappeared. Can you share your vehicle mileage and whether you notice the issue more during specific maneuvers? Also, have you had any recent work done on the suspension or steering components? This info would help determine if your case is similar to what I experienced. Worth checking if any software updates are available for your model, as these can sometimes affect sensor calibration and alignment problems.

Thanks for the detailed response. My car has 74142 KM on the odometer, with the last service completed two weeks ago. The steering issues started gradually after that service. The sensor failure symptoms get worse during low-speed maneuvers and parallel parking. It feels like the electronic stability system completely disengages at times, especially when making tight turns. No recent work was done on the suspension or steering components during the service. The steering column seemed fine when the mechanic checked it, but they did not perform any sensor-specific diagnostics. Your experience with recalibration gives me hope this might be a relatively straightforward fix. Will book an appointment focusing specifically on sensor replacement and diagnostic testing.

Thanks for the additional details about your Smart Forfour. The timing of your issues starting after the service is quite telling, as it matches what happened with my ForTwo. After reading about your specific symptoms during low-speed maneuvers, I am even more convinced this is related to the angle sensor calibration. My car showed identical behavior, particularly when parking, the electronic stability would disengage during tight turns just like yours. The steering angle sensor in these models can actually get miscalibrated during routine service work, especially if the battery was disconnected. Even though no direct steering work was done, the recent service might have triggered this issue. In my case, the workshop first ran comprehensive diagnostics on all automotive sensors to rule out other problems. They found the angle sensor was reporting incorrect values to the stability control unit. The fix involved electronic recalibration rather than full sensor replacement, which saved considerable cost. Since your symptoms match mine so closely, suggest asking the workshop to: 1. Check sensor calibration before replacing parts 2. Verify electronic stability system communication 3. Test power steering assist levels at different speeds Most steering sensor issues on these models are software-related rather than hardware failures. Getting proper diagnostics could save you from unnecessary sensor replacement costs.

Thanks everyone for the helpful responses. I wanted to follow up and share what happened with my Smart Forfour. Took it to a specialized workshop yesterday. Their diagnostic testing confirmed the traction control and steering issues were indeed linked to the angle sensor calibration, just as suggested. The technician found the steering angle sensor had lost its reference points during my recent service. The fix was actually simpler than expected, no sensor replacement needed. They performed a complete recalibration of the automotive sensors, particularly focusing on the angle sensor in the steering column. Total cost came to 165€ and took about 90 minutes. The steering now feels perfectly normal again, with proper power assist restored. The electronic stability system is working correctly, and those annoying vibrations have completely disappeared. Really glad I asked here first rather than assuming I needed expensive parts replaced. Will make sure to mention the sensor calibration requirement to my regular service center for future maintenance work.