Ignition Starts, but ready light and dashboard light off

Sounds like 12v battery replacement didn't go well... Possibly loose connections? Or possibly you bought an Optima pack? They don't do quality control the same way other battery sellers do it.

 

Get in the car. With your foot NOT on the brake, press the power button. The MFD should turn on. Does it?
Press the power button again, the dash should come alive. Does it?
Put your foot on the brake, press the power button again. The car should go ready and should go into it's warmup routine. Does it?

If the engine actually starts, then the car made it to ready mode. It may not indicate "ready" or any other information visually if the combination meter has failed.

I went to start my car and the engine turns on, but the dashboard is completely dark and the ready light is off.

The engine is not going to start if the car isn't in READY mode. Did you try putting it into gear and driving it? If it's a combo meter failure, you'll still be able to drive, even though the dash is dark.

 

welcome!

perhaps a bad combo meter? can you drive it?

 

If you access the battery in the hatchback on the right side. You can unplug the battery from the top (not the normal battery connection) the top part has 2 plugs. Unsnap the larger of the 2 for 30 seconds and then plug it back in. Turn on car and it should work. We had this problem in our 2007 model that Toyota had no idea how to fix it. Battery was fine. Check out the video on YouTube as well. It will walk you through it if you have trouble.

 

Congratulations, you are experiencing the classic symptoms of Combination Meter failure. Often, this 'blank out' occurs randomly for a while and progressively happens more often, eventually going to complete failure. Typically happens more often in colder weather. Sometimes, it's a one shot deal and it's done. Sounds like you may be falling under the one shot...

Matt at Texas Hybrids ( a member on the Forum) was one of the early pioneers of repairing these meters. I believe his company charges around $225 to send you an updated meter assembly, programmed to your odometer mileage and refunds $75? when you return your old one to him. Many people have swapped out their own assemblies, as the dealership will want your first-born.

 

Oh it will continue to happen alright to the point where you will not be able to shut the car off without disconnecting the 12 volt battery in the hatch which is loads of fun. It gets worse fast.
The colder it is outside the worse it gets. Does not like cold.

Texas Hybrids on this site is the guy to use. Not sure what the price is these days for a new combo as I bought mine from him 2 years ago but I think it was $100 for the whole module.

 

If you need a battery replacement you can go to. Prius hybrid repair call 4109197618 there in annapolis md