2015 Prius Trim 2 subpar MPG

Hard to prove it wasn't owner neglegence, to wit: leaving a door open or map light on. That said, it happens. Especially when cars sit on dealership lots for months.

Ours was dead-as-a-door-nail when we bought, it was 15 months past it's manufacture date, with about 10 km on the odometer. The salesman "had it running for us", when we showed up for a test drive. The ruse fell apart when we had to go back out and restart it to check something, after the drive.

But if he's driven it for a few months, harder to prove. Maybe everyone car shopping should take along a Solar BA5. Or a digital load-test should be mandatory part of the PDI. You pay enough for it.