Smart Forfour Battery Sensor Causing Start-up Issues

Having experienced similar battery sensor issues with my Smart Fortwo (2015, 1.0L gas), I can relate to these symptoms. The weak lights and starting problems matched my situation exactly, initially suggesting a simple battery problem. Battery testing revealed the issue wasnt the battery itself, but rather a faulty battery sensor that was sending incorrect voltage readings to the car computer. This caused the charging system to malfunction, leading to improper battery maintenance and eventual starting problems. The fix required replacing the complete battery sensor unit, as these components arent serviceable separately. The repair proved significant since a malfunctioning sensor can cause long-term damage to both the battery and charging system if left unaddressed. A proper diagnosis involves checking battery health with specialized equipment that bypasses the cars own sensor. When the external reading differs notably from the cars internal measurements, it typically confirms a sensor fault. For anyone facing similar issues, getting a comprehensive battery system diagnostic is crucial before replacing parts. The symptoms often mimic a dying battery, but the root cause can be more complex.

I faced similar low voltage issues with my Smart Forfour last winter. The vehicle diagnostics pointed to a failing battery sensor too. After getting it fixed, my starting problems and dim lights cleared up completely. The battery charge level now reads accurately and I have not experienced any related problems in the past 6 months. The battery testing showed the original battery was still good, it was just the faulty sensor causing issues. Did you end up getting yours fixed? Would be helpful to know the repair cost you paid and if you have noticed any other electrical gremlins since the repair.

Just had the battery sensor replaced last month after confirming it was the root cause. The repair totaled 315€ and completely resolved both the starting issues and dim lights in my Smart Fortwo. The vehicle diagnostics now show accurate battery health readings. A thorough battery testing confirmed my original battery was still in good condition, just like your case. The faulty sensor was causing improper voltage readings and affecting the charging system. Since the repair, battery maintenance has been optimal and all electrical systems are working normally. The battery sensor replacement made a clear difference, no more electrical issues or warning lights. The car starts perfectly even during cold mornings. Getting the proper diagnosis and fix was worth it to prevent potential damage to the charging system.

Thanks for providing me with your information. Last week I took my Smart Forfour to a certified mechanic after dealing with similar battery sensor problems for months. The total repair came to 290€ including the diagnostic work. The mechanic ran a complete vehicle diagnostics test which confirmed the faulty voltage sensor was causing my starting troubles. They found my battery was actually fine despite the incorrect readings. After replacing the battery sensor unit, all my electrical problems cleared up immediately. My car now starts perfectly every time and the lights are back to full brightness. The voltage readings are stable and accurate according to the follow-up testing. Really glad I got it properly diagnosed instead of just replacing the battery like my previous mechanic suggested.