Leaderboard

If it hasn't been done (I doubt it), see if your dealer can perform CSP 15B04 - read it here. It seemed to clear up dead 12v battery problems for a lot of us years back. It does sound like you may be having overnight 12V battery drain issues. A good (or new!) battery can be drained beyond full discharge (below 10.5 volts) when the problem occurs. I once saw mine down around 4 volts! You can charge it back up and it may load test OK but keep doing it and the battery is progressively degraded. What happens when you try and start the car depends on how low it went. If it only went down to maybe 8 volts (?) it might still start with you unaware of what happened. Or you might have some errors. At some point the car won't start and has to be jumped. You might get a cheap voltmeter and plug it in the 12v jack in the back (it doesn't turn off). Check it often and see what is going on.