VW T-Cross Key Fob Issue Despite New Battery

I had a similar issue with my VW Polo from 2017. As someone who does basic maintenance but leaves complex issues to professionals, let me share my experience. Like you, my electronic key stopped working properly and the battery warning stayed on even after replacing the fob battery myself. After struggling for a few days, I took it to a workshop that specializes in auto key programming. Turns out the key fob had a faulty circuit board, not just a dead key battery. The technician explained that sometimes moisture can damage the internal components, causing these persistent errors even with a new battery. The repair cost was 37€, which included reprogramming the electronic key and clearing the error codes. Much cheaper than replacing the entire key fob unit. To better assist you, could you share: Does your spare key work normally? Did you notice any exposure to water/moisture before the issue started? Are there any other warning lights on the dashboard? Can you still start the car using the physical key hidden in the fob? This information would help determine if youre dealing with a similar circuit board issue or something else.

Latest service was at 12000km, about 2 months ago. The spare auto key works perfectly fine, which helped narrow down the issue. The physical key also works for manual door access, but the electronic key functions remain unresponsive. No water exposure that I recall. The only warning is the key battery alert on the dashboard. What stands out is that my fault happened right after parking outside during heavy rain last week. The car key was in my pocket, but perhaps moisture got in somehow. Your experience with the circuit board issue sounds very similar to my symptoms. Would it make sense to try the reprogramming route first, since its cheaper than a complete key fob replacement? Just want to avoid unnecessary costs if a simpler fix exists.

Thanks for those extra details about your situation. The timing with the heavy rain definitely matches my experience, moisture damage is a common culprit with auto key problems. Since your spare key works fine and the issue started after rain exposure, it strongly suggests the circuit board problem I encountered. In my case, the workshop found corrosion on the contacts inside the key fob, which caused the key battery warning to persist. I would absolutely recommend trying reprogramming first. When my T-Cross had this issue, the workshop first attempted a system reset and reprogramming, which solved the problem. They also applied a protective coating to prevent future moisture damage, something worth asking about. The total repair cost for my key fob, including diagnostics, reprogramming, and protective treatment, came to around 40€. A complete key fob replacement would have been over 200€. A low voltage warning that persists after battery replacement is often a sign of circuit issues rather than an actual battery problem. Since your symptoms match what I experienced almost exactly, theres a good chance you can avoid the more expensive key replacement option. Just be sure to mention the rain exposure when you take it in, it helps the technicians focus on the likely cause right away.

Thanks to everyone who provided input on my key fob issue. I just got back from the workshop and wanted to share how it turned out. The diagnosis confirmed it was indeed moisture damage to the circuit board, not just a low battery problem. The rain exposure last week had caused some corrosion on the internal contacts. They were able to repair and reprogram the key fob, plus added a protective coating to prevent future issues. Total cost was 45€ for the complete fix, way better than the 200€+ quoted for a new key fob replacement. The key battery warning has cleared from the dashboard and all electronic functions are working perfectly again. Really glad I tried the reprogramming route first instead of jumping straight to replacement. For anyone else facing similar issues with persistent key battery warnings after changing batteries, definitely worth checking for moisture damage and trying a repair before buying a new unit. Going to be more careful about keeping the key fob dry during rainy weather from now on!