Thanks Herbie, much appreciated. Sounds like there isn’t anything that visibly monitors the 12v.
I picked up a used approved 450HL last weekend and drove it long distance home (plus a fairly long midweek run too). This morning I started ignition but not the engine, and was installing a child seat for a couple of minutes when a warning noise sounded and it asked to be put into P as hybrid mode not working (something like that). It was already in Park though… long story short I couldn’t get the engine on
AA came out later and diagnosed a flat startup 12v. They’ve recommended I get to a dealer to do a drain test and potential replacement.
The theory was combination of cold weather and maybe sitting in a dealership for a few weeks pre sale, but underneath that likely a faulty battery.
I understand the petrol engine charges the hybrid battery which in turn charges the 12v. So I’m a bit worried it’s the hybrid battery that could be the issue. Hoping it’s just the 12v though.
I’ve read on this forum that others use a standalone charger to keep the 12v alive when they’re not using the car much. But any tips on this and the whole situation would be appreciated.
Many thanks
John