Reving after releasing gas.

This might be my issue. after . I have a 2016 prius c. After it runs 45-50 minutes . when i release the gas pedal it revs a few seconds. . once this starts the car says EV is not available at the moment. If I shut the car down for 4 hours it goes back to normal . started a few weeks ago. I will check the fan. went to the dealership and they didnt see anything . I also called Toyota about it and they logged a case but had no info .

 

you can break those clips easy. less than 2 bucks from the dealer. they should add this vent cleaning to their maintenance service every 15K. Talked to the dealer and also Toyota direct and they said they have not gotten complaints about it . I filed a complaint so it is on record with them . i have 2016 prius c and the engine rev along with it not going into EV mode started 2 days ago . I cleaned the battery air intake vent and it now is working properly . Not hot enough to set the battery alarm off so that is why diags dont pick it up. Eventually you would get the over heating light. 100% sure this is the issue. Thanks everyone . Saved me a few hundred bucks and aggravation.

 

Fan cleaning fixed it . thanks

 

I definitely think this is the case. I was having the revving issue in two contexts and this is consistent with the changes I've made.

First, I've had the Toyota techs tell me my car has too much dog hair and that's coincided with the revving issue. Thinking back, it's certainly correlated with the battery status and temperature.

Second, my hybrid battery recently failed and I had to get it replaced. I drove around 100 miles with just the ICE engine and noticed that the car was doing the revving thing every. single time. I drove on the freeway and noticed it happened at all speeds and regardless of incline or decline. Then, I changed my battery to a brand new one and the issue went away immediately.

Both of these suggest to me that the revving is done to protect the battery from high temps, and overcharging, AND to make it so the driver still feels like the car is slowing down around the same amount as it would if it was capturing energy. In other words, the car wants to make it feel like its engine braking always (either by electric capture or ICE engine braking) whenever letting off the gas. All this to say, I'm confident the overrevving is usually nothing and most folks need to just vacuum their car, make sure the vent can get plenty of air, and clean the vent.

Also, the vent goes from behind the driver seat, under the passenger seats, and out through the right side of the trunk. Look for the little vent on the right end and make sure that isn't blocked too!

As an aside, I bought a Lithium battery to try that out as rebuilds are crappy and the original ones are more expensive (and older technology). So far I love it!! I have noticed that the electric-only range is longer! Might just be my perception, however, since I am going from a busted Nickel battery to a brand new Lithium battery so not a true apples-to-apples comparison.