Honda Gienia Check Engine + Fuel Flap Sensor Problems

Hey there! I have some experience working on cars, and I actually dealt with a similar issue on my 2014 Honda Civic (pretty close to your Gienia). The Civic line has had comparable wiring problems. I had basically the same symptoms, warning lights popping up and error codes related to the fuel door. My mechanic found that the wiring harness to the fuel filler flap was damaged and causing all sorts of electrical gremlins. They ended up replacing the entire wiring harness, which set me back about 155 Euro, but it completely fixed the problem. Before I share more specific details though, can you tell me if you've noticed any other electrical issues? Also, does your fuel door still open normally? This would help me understand if you're dealing with exactly what I faced. BTW, have you had the fault code read? Knowing the exact code would help confirm if it's the same problem I had.

Thanks for sharing your experience! Yes, the fuel door opens fine physically, but the warning lights are what concern me. I've had regular services done, last one at 46647 KM, and this is the first electrical issue I've encountered. Haven't noticed any other electrical problems yet, but I'm keeping an eye out. I'll definitely get that wiring harness checked, seems like a common issue worth investigating. Thanks for the tip about checking the fault codes too, I'll get those read and report back!

Hey again! Thanks for the follow-up info about your Gienia. Since you mentioned your fuel door opens fine physically, that's actually exactly how mine started too. The mechanical part worked perfectly, but those pesky warning lights just wouldn't go away. Looking at your mileage (46647 KM), you're right around where I started having these issues. In my case, the wiring started acting up at about 45000 KM. Before replacing the entire harness, my mechanic tried cleaning the connections and checking for loose wires, but that only helped temporarily. The warning lights came back after a few days. Just a heads up, if it is the wiring harness like in my case, you might want to get it sorted sooner rather than later. I waited a couple of months, and it eventually started causing some funny readings on my fuel gauge too. Not fun when you're trying to figure out how much fuel you actually have! Definitely get those fault codes read and let me know what they say. If they're similar to what I had, I can share more specifics about the repair process. The fix itself wasn't too complicated, but finding the right parts took a few days. Keep us posted!

Based on the conversation, here's how I would reply as: Thanks so much for all the detailed information! That's really helpful to know about the fuel gauge issues that could develop, definitely don't want to end up guessing how much fuel I've got left! I managed to get the fault codes read today. Turns out it's showing P0457, which from what I understand is related to the fuel cap/filler area. I'll get my mechanic to check the wiring harness first thing tomorrow. You've probably saved me a lot of troubleshooting time with your experience! It's reassuring to hear the repair wasn't too complex, even if finding parts took some time. I'll start looking into parts availability right away. Really appreciate you sharing your experience with this, it's given me a much clearer idea of what I'm dealing with. Will definitely update once I get it sorted!