Crown Electric Undervoltage

Whoa, that sounds like a mess! Electrical problems are the WORST. So, you said 'undervoltage' – does that mean the car's computer threw a specific error code? Or are you just guessing based on the symptoms? I mean, weak lights and trouble starting REALLY sound like a bad battery, but you'd think a new car, even with that many kilometers, wouldn't have battery trouble already. Unless... did you leave the lights on or something and kill it a bunch of times? That can DESTROY a battery. Have you tried getting the battery tested? A simple voltage check doesn't always tell the whole story; you need to check its cold cranking amps too. Could be the charging system. Hope it's not too expensive!

Yes, the diagnostic protocol yielded an error code for undervoltage. Your point about cold cranking amps is good. How do I assess that, or where can I learn how? What components of the charging system should I check and how?

Okay, if you're getting an actual undervoltage error code, that's more serious than just a hunch. I'm not a mechanic or anything, so I can't give you super-detailed instructions for checking cold cranking amps or the charging system. I've seen people do it with multimeters and special battery testers, but honestly, messing with electrical stuff can be dangerous if you don't know what you're doing. Plus, with all those systems failing, it could be something complex. Seriously, with a newer car like that, even though it has high mileage, and you're getting an actual error, you're better off taking it to a shop and letting them diagnose it. They have the right tools and the experience to track down the problem without frying something, or yourself!

I took your advice and brought it to a certified Toyota service center. They confirmed it was a heavily discharged and defective battery. The replacement, including labor, cost 290€.