Hey there! I dealt with something really similar on my 2014 Porsche Boxster last winter. I've got some experience working on cars, and this issue was pretty frustrating. The symptoms were exactly like yours, weak starts and funky lighting behavior. Took it to my regular Porsche workshop, and yep, it was the battery temp sensor. They replaced it, recalibrated the system, and everything's been perfect since. Cost me around 315€, not cheap, but it beats replacing the whole battery! Before we dig deeper, what's your exact engine variant in the Cayman? With these Porsches, small details can matter a lot. Also, have you noticed any warning lights on the dash? (BTW, I also had a 718 Cayman before the Boxster, so I'm quite familiar with these platforms) Let me know these details, and I might be able to share some more specific insights!

Thanks for sharing your experience! My car's at 91635 KM and just had its service last month. Initially, I also thought it might just need a new battery, but the symptoms are too similar to what you described. That's really helpful to know about the sensor fix, 315€ sounds much better than shelling out for a new battery. No warning lights on the dash yet, thankfully. I've got the base 2.7L engine, and everything else runs perfectly fine. Did your mechanic mention how long the repair took? I'm trying to figure out if I can squeeze this in before a road trip next week.

Hey again! Yeah, no problem, happy to help out! My Boxster was around the same mileage (about 95,000 km) when I had this issue. The repair itself was actually pretty quick, took them about 2 hours total. Most of that time was spent on testing and recalibration after replacing the sensor. You should definitely be able to get it done before your road trip. Just a heads up though, make sure they have the part in stock before you go in. When I had mine done, they had to order it and I had to wait a couple of days. I know the feeling of wanting to get it sorted quickly, especially before a trip! One thing I forgot to mention in my first response, before they did the sensor replacement, my mechanic did a full charging system test just to rule out any alternator issues. Might be worth asking them to do that too, just to be on the safe side. Let me know how it goes! These Porsches are fantastic cars when everything's working right.

Thanks so much for all the details! Really appreciate the tip about checking part availability, I'll definitely call ahead. It's good to know it's just a 2-hour job, and I'll make sure to ask for that charging system test too. Better to be thorough! I'll try to get it booked in tomorrow morning. With a bit of luck, they'll have the part in stock and I can get this sorted before hitting the road. I've got a 6-hour drive ahead of me next week, so definitely want the car running at its best. Really grateful for your help and sharing your experience, it's made me feel a lot more confident about what I'm dealing with. Will update you on how it goes after I get it fixed!