VW Remote Key Problems: Quick Fix vs Workshop Visit

I had the exact same issue with my VW T4 2009 last winter, the dead key fob was showing similar symptoms. Being somewhat familiar with basic car maintenance, I initially thought it was something major with the central locking system. The dashboard warning about the key battery was spot on though. Took it to my regular workshop and turns out it just needed a key fob battery replacement. The whole thing cost 37€ including the new battery and labor. They also checked the central locking system just to be safe, but everything else was working fine. Since then, no more issues with keyless entry or central locking. These key batteries typically last 3-4 years depending on usage. The workshop mentioned it's a common issue with VW models from that era. What specific warning messages are you seeing on your dashboard? Also, how long have you been experiencing these issues? This info would help determine if your case is similar to what I encountered. Quick tip: If you notice the key fob range getting shorter before completely failing, that's usually a clear sign the battery is getting weak.

My T5 has 77876km and was last serviced in August. After seeing these responses, I checked the key battery using a voltage meter and found very low voltage, just 1.2V instead of the normal 3V. Seems like the battery is definitely the culprit here. The dashboard shows the classic key symbol with a red cross, exactly as described. The keyless entry started acting up about 2 weeks ago, with decreasing range before stopping completely. Given the similar experiences shared here, I will likely try replacing the key fob battery first before considering more expensive repairs. This seems like the most logical first step. Does anyone know the exact battery type needed for a 2011 T5 key? And roughly how much the battery itself should cost before labor?

Thanks for the voltage reading, that 1.2V definitely confirms what we suspected about the key battery being the issue. For the 2011 T5 key fob, you need a CR2032 3V battery. These typically cost between 2-5€ at most electronics stores. When I had this issue with my T5, I actually ended up replacing both key batteries since they were from the same period. The second one was still working but already down to 2.1V, so it made sense to do both while at it. The symptoms you describe, declining range followed by complete failure, match exactly what I experienced. The key battery warning with the red cross is the cars way of telling you its time for a replacement. If you are comfortable with basic DIY, replacing the car key battery is pretty straightforward. Just be careful when prying open the key fob housing. Otherwise, most workshops will do this quick fix for around 15-20€ labor plus the battery cost. One tip from my experience: after replacing the auto key battery, you might need to press the unlock button a few times to resync the key fob with the car. This is normal and doesnt indicate any additional problems.

Thanks for the helpful advice. I went ahead and bought two CR2032 batteries today for 8€ total. Figured I might as well replace both key fob batteries since they are probably equally old. The voltage meter was definitely useful in confirming the low battery issue. My local auto parts store had the batteries in stock and even showed me how to properly open the key housing without damaging it. Just finished replacing the first key battery and the keyless entry is working perfectly again. The dashboard warning disappeared after a couple button presses to resync. Range is back to normal too. Will tackle the second key battery replacement tomorrow, but glad to have solved this without an expensive workshop visit. Total cost was just 8€ for both batteries versus what could have been a much more costly central locking system repair. Really appreciate all the feedback here, saved me both time and money by addressing the simple low voltage issue first rather than assuming the worst.