Hello - looking at used 2021 Prime LE high-ish miles - what to check? battery/engine, red flags?

A new car dealer or exclusively a used car dealer?

Yea, it sounds like a lot, but some cars are just driven like that.

Yes - if you can figure them out. It's not easy trying to look at the screens and know what they mean the first few times, and for some screens even longer, much longer. And there are a whole lot of new ones than even Gen 3 Prius Plug-in

I don't have any experience with warranty claims, just remember your dealing with a dealer for them. Been to a local dealer lately?

Have you driven it yet?

Just keep checking both with and without using the VIM. Your bound to find something to give you more clues.

Same as just above. Have you a Toyota Owners account?

The OEM gauges and DrPrius are a good start. Yes DrPrius works / is supported for the Prime.
But, I just did a Battery Life Expectancy test yesterday which is one of the options for DrPrius subscription ($12 and was worth it for me), and it didn't function all that well. Even though I was able to figure out how to get the test finished, it showed a charging error and a lower than expected estimated capacity left.
So, now I know how to run that test and understand what the test is looking at and what to expect. (After all the app was originally built for a Gen 2 Prius Hybrid Battery). The free part of the DrPrius apps works well for the Prime and some of the advance features also work well, others are not up to speed yet.

Only advice I can give is to that is test drive a Gen 4 Prime at a dealer to see if you notice a difference.

 

Do your research for the IR tax credits. I don't know about the 2024 tax year, but for 2023 make sure the sales price (including all dealer handling..., excluding taxes and licensing fees) is less than $25,000. Also, check that the dealer will do the paperwork for the IRS tax refund. This got me a $4000 incentive. I'm sure things have changed for 2024, and there are other limitations. Your dealer probably won't be any help in knowing the IRS tax code, so you'll need to do your own research here.

None of the dealers I went to seemed to know that much about a Prius in general, and were even worse when it came to the Prime. If you want to see what the EV mode is like, there's a way to charge the battery using the ICE engine. Lookup YouTube videos on how this works. Your dealer will probably be no help here either.

One of the things I did was to go through the Carfax and see what the interval was for the oil changes. I noted how long before the first one too. It was a bit disappointing.

If you go through the trip meters (Trip button on the steering wheel), you should get to one with the overall mileage - which also shows the overall MPG, provided nobody has reset that. Given the car has around 50MPG for the ICE engine, you can get a rough idea of how many ICE miles the previous owner was putting on it versus driving it in the EV mode. The one I got had an overall 75MPG, which to me means it was roughly half and half, so a 10K mile oil change was more like a 5K mile oil change as far as the ICE is concerned.

I stopped going to the dealer for oil changes when something happened to my Gen 2 and it lost an engine after 125K miles. They also screwed up the plastic underbody panels after a freeway encounter with a jackrabbit, and a wheel bearing change.

I stopped going to the oil change places when the oil change door on the bottom of my Gen 3 never seemed to stay closed after they changed the oil and filter. Those changes are on the Carfax.

Now I do my own wheel bearings, oil changes... None of this shows up on the Carfax.

I would be a bit leery of the northeast "salt belt" area cars. Definitely give it a look underneath and see if you see signs of rust. Check that the cat hasn't been stolen and replaced with a cheap aftermarket - especially if you've gotta get a yearly inspection.

 

Yep; the odometer & trips will give you an idea of how the car was driven. The main MID will read 70K and next to it should be overall mpg. That should be in the neighborhood of 75 mpg. I'm 90% EV and mine reads 133 mpg and I only got 37K miles on mine. That's assuming the battery wasn't replaced or died - then everything resets.
If your not sure, take the car to a Prius expert or body shop; to ensure it hasn't been in an accident and the title hasn't been washed/cleaned.

Hope this helps.

 

If it was a "fleet lease" with a large organization, all maintenance would've been done in-house.That's part of the deal for the steep discount they lease the car for.
When I was a field service technician, we were given a coupon book with our cars. Coupons was good at any Firestone automotive center. Firestone reports to Carfax, whomever did the maintenance didn't. Most large fleet organizations has a good handle on fleet vehicles maintenance, but there are outliers.

 

Yea, something is wrong with the DrPriujs screens. Could be your adapter, phone or your download / install of the app. Those screenshots don't help much. Does DrPrius show the same issues in your currently owned Prime XLE?
My 2017 Prime Voltage range is 375.xx fully charged and 330.xx volts when the engine switches on. The 328.xx volts and the charge and discharge numbers make it hard to judge the others, especially the most empty internal resistance blue colored bars at the bottom. The second screenshot in your post #7 above, shows the internal resistance like mine usually does which I consider a good level.

To give you an idea why what I call a internal resistance graph reset with my Prime, I've been driving all winter and only using the top half of the battery capacity ( never going below 50% SOC ) When I took this DrPrius screenshot, I'd driven EV using all the battery capacity than used charge mode to recharge all the way back to charge modes limit of 80% SOC. Internal Resistance started getting higher and a few or the blue bars went blank as I reached the the voltage when the engine starts up. It stayed that way while I was in charge mode until I reached 80% SOC and the Prime switched back into EV mode about 2 miles for home. By the time I'd gotten home this is what the screen looked like.

It's not the first time I've seen this happen, but it dose seem to happen mostly when using a part of the batteries capacity that hasn't been used for a month or two or three months. With me it's typically the lower half the batteries capacity that I don't use for extended periods of time.
Hop;e that's not to confusing. Those Dr Prius screens make it difficult to evaluate the battery accurately.

 

I'm looking forward to your new thread. If you have any extra screenshots to spare after you start your thread, if you wouldn't mind adding one or two to my old thread, it could use a couple besides mine and the one other one @srivenkat added.
Prime Traction Pack voltage report | PriusChat