Red warning light and check engine light

First, welcome to Prius Chat.

You likely need your dealer to read the trouble codes to really have a good guess. Report the codes back here and let the troubleshooting begin!

 

Check the engine oil level and make sure its not super low.
Then check the Invert Coolant pump operation by removing the Inverter coolant tank cap and with a flashlight look down into the reservoir and see if the fluid is bubbling or has good turbulence while the car is on. If not the Inverter Coolant pump has failed and must be replaced. very very common.

If engine oil level is correct and not super low and you have good turbulence in the Inverter fluid it could be many other things. Its a Master caution so its not kidding. Get the codes read asap.

There was a technical Service Bulletin out for the pump I'm hoping your car has seen the dealer in the last few years and got the free pump.

 

And how's your 12V battery?

 

This has happened to me several times. Red triangle comes on with drippy oil can symbol and goes off immediately. Oil level always fine. Once, my wife drove with red triangle on from the start. She got 1/4 mile from home and said it shut down. When I got there, all was fine. Perfectly normal operation. She didn't observe the problem screen. Dealer found lots of codes, said most involved cascading--one led to another, etc. Suggested replacing injectors at $1000. Had replaced coils at $900+ to try to fix another check engine light problem. Coils were one of the codes stored. No thanks. Car has 150k and no observable problems. No check engine, no triangle. I'm NOT saying to ignore problem, but the codes don't necessarily suggest right action, at least not in my case. I'm no expert, just my two cents.

Posted via the PriusChat mobile app.

I wouldn't object if someone suggests deleting my post and someone else does do. Anecdotes aren't reliable means of solving problems.

Posted via the PriusChat mobile app.

 

I actually get this combined with beeping when the key/fob is too far from the dash, it goes away when I put the key closer to the slot.

 

So, perhaps a weak key fob battery?

 

If that does not happen with the key in the slot, I would try a new one.

 

This is nonsense.

 

The easiest and best code you can hope for. Your electric inverter pump needs replacing.

 

Prius Code P0A93: Inverter Water Pump Failure - Luscious Garage | Hybrid Specialists