Smart Forfour Memory Lock Fault After Service Persists

The undervoltage issue you describe matches what happened with my Smart EQ Fortwo (2018) last season. The computer system kept showing persistent fault codes even after standard repairs. The ECU diagnostics revealed it was more than just a memory lock, there was an actual voltage drop in the low-voltage circuit. The root cause turned out to be a failing DC-DC converter that wasnt maintaining proper voltage for the 12V systems. While the workshop initially tried clearing the ECU fault codes, the warnings kept returning because the underlying issue remained unresolved. This was a serious problem that required attention since the DC-DC converter is crucial for powering essential control modules. The auto repair involved replacing the converter unit and recalibrating the power management system. After the repair, the fault codes cleared permanently. Worth noting that in electric vehicles, voltage-related issues can cascade into multiple system warnings. Having a specialist perform proper ECU diagnostics is crucial rather than just clearing codes repeatedly. The memory lock you mentioned is likely protecting the system from potential damage due to unstable voltage.

Thanks for sharing your experience. That sounds exactly like what I am dealing with right now. My Smart showed similar automotive diagnostics patterns after they cleared the control unit memory. A suggested checking the DC-DC converter too but I wanted to get more opinions before going back to the workshop. Did you remember how much the complete repair cost in your case? Also, have you noticed any other electrical quirks since they fixed the converter?

Having resolved this exact issue on my Smart EQ Fortwo, I can confirm the repair was successful. The workshop replaced the faulty DC-DC converter and corrected the active memory lock in the car electronics system. The total cost came to 240€ for fixing the undervoltage problem. Since the ECU fault was addressed, the vehicle has performed flawlessly with no electrical issues. The control unit now maintains stable voltage levels across all systems. The persistent fault codes that were previously stuck in the active memory have completely disappeared. The investment was worthwhile as proper voltage regulation is crucial for the longevity of electric vehicle components. Most importantly, the memory lock feature is no longer active since the underlying voltage problem was fixed, indicating the auto repair was done correctly.

I finally got the issue resolved last week. After reading about similar experiences here, I took my Smart back to a different workshop that specializes in electric vehicle control units. Their diagnostic scan confirmed the DC-DC converter was causing the persistent fault codes in the active memory. The repair cost me 280€, which included replacing the converter and clearing the memory lock properly. They explained the whole process and showed me the before and after readings from the car electronics system. Much more transparent than my previous mechanic. Been driving for a week now and all the warning lights are gone. The car runs smoother and the electrical systems are working perfectly. Really glad I followed up on this rather than letting the first workshop brush it off as a simple fault code issue.