Smart Forfour Trans Stuck in Emergency Mode, Fix Tips

I had a similar issue with my Smart Fortwo from 2008 with an automatic transmission. As someone with some basic car maintenance experience, I first suspected transmission problems too, but it turned out to be an electrical issue. The symptoms matched exactly what you describe, erratic shifting, transmission warning light, and poor transmission performance. My workshop diagnosed an undervoltage problem that was affecting the transmission control unit. The fix involved checking the battery, alternator, and electrical connections rather than a transmission flush or oil replacement. The total repair came to 240€, which included diagnostic work and fixing the electrical system. After the repair, the transmission went back to shifting normally. Before jumping to transmission maintenance solutions, it would be helpful to know: What error codes are showing up? Has the battery been replaced recently? Are there any other electrical issues like dim lights or slow starter? When was the last automatic transmission service done? Getting these details would help determine if your issue is electrical like mine was or if it actually needs transmission work. If it is transmission-related, a proper diagnosis would show whether you need a simple transmission oil change or more extensive repairs.

Thank you for your help with my transmission issue. The last service was actually quite recent, just 2000km ago, where they checked all fluids including the hydraulic fluid. The issue started suddenly after my mileage hit 120281km. My case seems different from yours since I already had the battery and alternator tested at the workshop this week. Both are working fine. The transmission definitely feels mechanical rather than electrical, there are actual hard shifts and odd noises when the automatic transmission tries to change gears. I will get the error codes scanned tomorrow to help pinpoint whether a transmission flush might help or if the transmission needs more serious attention. Will share those results in the forum once I have them.

Thanks for the update on your Smart Forfour transmission issue. Since your symptoms differ from my electrical case and persist despite good battery/alternator readings, this does point more toward a mechanical transmission problem. The hard shifts and noises during gear changes, combined with recent fluid checks, suggest this might be more than just worn transmission oil. The automatic gearbox may have internal wear or a failing solenoid, common issues at this mileage point. When my transmission was repaired after ruling out electrical causes, the workshop found metal particles in the transmission oil, indicating internal wear. The full repair included: Complete transmission oil flush, Replacement of worn solenoids, New transmission filter, Fresh hydraulic fluid Total cost was around 1200€, but this prevented a complete transmission failure which would have been much costlier. Getting those error codes scanned is the right next step. This will help determine if specific transmission components are failing. Looking forward to seeing those results to better guide the repair approach. Consider requesting a transmission oil analysis when you visit the workshop, this can reveal if internal parts are wearing excessively.

Getting the error codes checked tomorrow sounds like the smart move. Your mechanical symptoms of hard shifts and noises during gear changes make me think this could be more serious than my electrical problem was. The fact that all fluids including transmission oil were checked recently, and you still have these issues, suggests something might be wearing inside the automatic gearbox. I hope the diagnostic scan helps identify whether its a failing solenoid, worn transmission components, or something else causing the problems. Good to rule out the simpler electrical issues first like you did with the battery and alternator tests. A proper hydraulic fluid analysis might also reveal if there are metal particles indicating internal wear. Will keep an eye out for your update with the error codes. That information should help determine if a transmission flush might help or if more extensive repairs are needed. Just want to avoid a complete transmission failure which would be much more expensive to fix at this point.