Went from Neutral to Reverse without breaking - Check Hybrid Engine warning and ICE won't start

how fast were you going?

 

The computers protect the vehicle from being shifted when damage could happen. However if you've had a rough running engine due to bad head gasket in the past there may of been damage to the transmission dampener, which could of finally failed entirely during this event. There's other options, but this is my first thought. Soon as you find out what the error code is related to dash lights we can get specific on repair options.

 

If you open up your engine coolant reservoir you'll most likely hear a suction sound and will be low on coolant. Also your EGR system is likely clogged and needs cleaning. Basically Toyota screwed up huge with gen3 engine design and there's no such thing as a Gen3 Prius with 300K miles unless it has new head gasket, new piston rings and lots of regular EGR cleanings.

The best fix is to buy a used Gen4 Prius engine from a wrecker and put that in. There's a guy on here in Oklahoma who will install that engine for $1500 in your driveway in a day. So if you have a friend or family member closer to Oklahoma than Ohio is and can get an engine shipped to their place and they let you borrow the driveway for a day for an engine swap, that's the least expensive solution for the 2010-2015 era when Toyota destroyed their reputation with an awful Prius engine.

 

If it’s your time…

 

What’s the miles?

 

Nothing mechanical happens in the switch from neutral to reverse. Nothing grabs, releases or changes pressure or angle on anything else. It's a purely electrical change.

The fail-to-start and rough starts are coincidental. They're a real problem to be addressed; but there's no connection with what you did from the driner's seat.

 

yeah, i suppose mileage and head gasket would be something to think about, but maybe just a computer glitch?

 

thinking about this again, "thud" may well be where it hydrolocked and bent a rod.

 

would the engine be working fine with a bent rod?

 

It is not running fine.

 

no, but 'rattling came back after running fine' doesn't sound like a bent rod.

 

I’m then going along with @PriusCamper’s theory, that (due to EGR neglect and consequential head gasket failure), the damper between engine and transaxle has failed. If you can get under there, there’s a black plastic panel at the junction: pry it off and look for damage, say pieces of damper spring.