2009 Prius - Revving sound??

It's probably just coincidental but I had 12V battery replaced about a week ago. I'm noticing an extra noise coming from the engine. No rattling just a slight revving sound as if engine is working harder than usual and it continues even when my foot is not on the gas. Not in electric mode. Car doesn't feel off in any way except this sound.

Almost like a subtle motor boat sound driving along with me. Wondering if it's the beginning of an exhaust issue but it's coming from the front of the car.

I looked at my records and back in 2019 I was forewarned during dealer inspection that the muffler is rotting but not a word about it during the past few inspections and it passed emissions over the summer.

I have a long drive this upcoming week so I'll need to have service do a test drive on Monday. 189,000 miles. Any ideas?

I'm replacing this car as soon as I can make a decision on what to get next...Prius FWD/AWD or Prius Prime...plus the long wait for these cars to appear on the lots. Hoping to avoid additional expenses before replacing it. : / Test drove a 2020 Prime today but it costs as much as a 2022 plus only 1 year left on warranty.

Thanks!
Maria

 

Ok. I didn't know about "inspection mode". I was trying to figure out how I could get motor running while looking under hood. : } We're in the middle of some cold winter weather so I'll try this tomorrow. Really appreciate the advice. Thank you!

 

Yikes! Well that sounds like a nightmare. I guess I’ll have to wait and see. No warnings or codes yet.

 

I have an iPhone 7 that is so full I have most of my apps off. : / Unfortunately my Prius tech skills include changing engine and cabin filter and adding oil. I’m thinking I’ll have to get dealer to test hybrid battery on Monday. The screen that shows battery usage/charging looks normal and no codes or engine light yet. I have noticed a loss in mpg but I thought that was due to winter. I’m averaging about 43 mpg.

Maybe I should’ve put a deposit on that 2020 Prime today. Oh well…

Appreciate your help.

 

Wow…I’m not used to such attitude on this forum. You’re making a lot of assumptions and I’ll leave it at that.

 

Thank you. I was thinking the app wouldn’t load since others don’t but no problem. It must use very little space. Just read through Dr Prius info regarding which OBD units to buy. I guess I need to cancel this long distance appointment until I can figure this out. Wish I knew someone with OBD reader since it will take a few days to receive one. Is there an area in this forum to ask if anyone in my location might have an OBD reader I could borrow?

I was initially going to start by having the service manager do a quick free test drive. He’s been accommodating in the past. If it’s the hybrid battery failing I now know I need to use this OBD reader to test status. As I mentioned I’m not going to replace hybrid battery if that’s the issue.

It’s complicated. I’m technically very poor and have zero support. In place of small monetary inheritance I was recently told I would be gifted with a new car instead. The complication is the waiting time for these cars to be available.

 

I’m researching this now. My MacBook is as old as my car. : }

 

I just went out to start car to at least see the status of the battery charge from cold start in 30 degrees and the green bars are at the top.

Thank you so much. I barely slept last night after the assumption that it’s the hybrid battery. I’ve had the hybrid battery tested twice. Once in 2015 pre purchase and then a hybrid specialist ran diagnostics on it in 2017 with no issues. I just drove it and quickly went to 60 mph to see if battery gauge changed at all. No change. I did take a video of the engine sound (pretty loud under the hood but I have nothing to compare it to). I also recorded the sound while I was driving. From inside cabin it almost sounds like a loud fan noise.

When looking under the hood it sounds like it’s coming from around the engine air filter area. The smaller square liquid container to the left of it (haven’t looked in manual yet to see what that is) seemed to be vibrating a bit too. Is that normal?

Really appreciate your reality check. You are all (well except for the one condescending remark) so helpful and I do appreciate your help.

 

Thanks, Bisco. I know this is unrelated but I did have a mouse nest in my cabin air filter at last inspection. It at least didn’t eat through the filter.

 

I only did a quick down the street and back this morning. Last night when I was driving home it was doing what looked like normal recharge cycle. Down into the blue and back up.