VW Passat Key Fob Dead, Simple Fix or Complex Issue

Having experienced this with my 2018 VW Arteon Hybrid, a low battery in the car key was just part of the issue. Initially, the electronic key showed similar symptoms, inconsistent central locking and keyless entry failures. Replacing the key fob battery alone did not resolve all problems. The main cause was a combination of a weak car key battery and a degrading main vehicle battery. The low voltage from the aging main battery was affecting the key detection system. The fix required: New CR2032 battery in the auto key, Testing the main 12V battery, Replacing the main battery due to reduced capacity, Resetting the key recognition system Even with a fresh battery in the car key, if your main battery is weak, the keyless system can act unpredictably. This is a known issue with VW hybrids because the key detection systems are more sensitive to voltage fluctuations. Suggest having both batteries checked, its not a major repair but needs proper diagnosis to avoid recurring issues.

Thanks for sharing your experience. Your situation sounds exactly like what I went through with my Passat last month. Same symptoms with the electronic key acting up. Changed the fob battery first but still had problems. Turned out my main battery was also going bad, just like in your case. Would you mind sharing what the total repair cost was? Also curious if youve had any issues since getting both batteries replaced. My key detection is working fine now but always good to know if theres anything else to watch out for.

Thanks for asking about the follow-up. Since getting both the auto key and main battery fixed last year, the keyless system has worked flawlessly. The key battery low warning disappeared right after the battery replacement service. The cost breakdown was reasonable, just 37€ for the key battery replacement including programming. I actually saved money by addressing the battery issue early, as waiting too long can sometimes lead to more complex electronic problems in these keyless systems. A useful tip: I now keep a spare CR2032 battery at home. Even though car key batteries typically last 2-3 years, having a backup ready helps avoid getting stuck with a dead key situation. The main vehicle battery has also been solid since replacement, with no more voltage-related warnings or key detection problems. Just keep an eye on your dashboard for any new low voltage warnings, thats usually the first sign if the system starts having issues again. But with both batteries replaced, you should be good for several years of trouble-free operation.

Thanks for the advice. Just got back from the mechanic and wanted to share how it went. The diagnostic confirmed both battery issues, exactly what was discussed here. Total cost came to 320€ for everything including the main battery, fob battery, and labor. The mechanic showed me the voltage readings from the old main battery, which explained why my electronic key was acting up. They also programmed the new key fob right there. The whole service took about an hour. Best part is the keyless entry works perfectly now. No more dead key warnings on the dash, and the auto key responds instantly when I approach the car. Such a relief knowing it wasnt a major electrical problem. Quick tip for others: The service center mentioned these key detection issues are pretty common when the main battery starts getting weak. Getting both batteries checked early definitely saved me from bigger headaches later.