Reliability:
The 2020+ Highlander Hybrid uses the same powertrain as pretty much all modern Toyota car-based hybrids (2018-2024 Camry, current Rav4, current Sienna, and so on). It is an extremely reliable powertrain that doesn't have a lot of widespread issues assuming that you maintain it properly. Regular maintenance is key to a happy ownership experience- including cleaning/replacing the hybrid fan filters.

You might want to go to YouTube and search up the CarCareNut's channel- he has a lot of Toyota hybrid-specific videos that are really informative- you don't have to just stick with the Highlander Hybrid (as I mentioned, many other Toyotas and Lexus models use the same exact hybrid powertrain as the 2020+ Highlander).

Maintenance:
Maintenance is no different than any other modern Toyota- with the exception that you'll need to clean/replace the hybrid fan filter from time-to-time. In many ways, maintenance costs are generally lower (until the vehicle gets older and the hybrid battery itself needs to be replaced). Things like brake pads, rotors, and calipers all will likely last longer on a hybrid compared to a non-hybrid, as the vehicle's regenerative braking system takes a lot of the stress and wear off of those components.

Toyota calls for basic maintenance every 5,000 miles (inspection and tire rotation), oil changes and additional inspections every 10,000 miles, and other components to be inspected or changed a bit less frequently. You can look through the recommended maintenance schedule on Toyota's website- go to the upper left corner of the home screen and click on 'owners', then 'manuals and warranties'... then select a 2020/2021/2022/2023/2024 Highlander Hybrid and scroll down and find the 'Warranty and Maintenance Guide'.

Personally, I would recommend oil changes every six months or 5,000 miles- not 10,000 miles. It's largely a personal decision though. The CarCareNut has a few videos that discusses oil change intervals on modern Toyotas- and they are worth a watch. He is a former Toyota Master Diagnostic Tech- and worked at a Toyota dealership for many years before opening his own shop in the Chicago area that works exclusively on Toyota and Lexus vehicles. He knows his stuff.

Mileage:
As the saying goes, your mileage will vary. Hybrids can get really awesome mileage if driven a certain way in ideal situations. Hybrids can get 'meh' fuel economy if driven hard or driven in less-than-ideal situations.

Getting the best mileage (which often can exceed official MPG figures largely depends on how closely you can match the 'ideal' conditions:
-Driving at a leasurely pace with gradual acceleration and braking.
-The ambient temperature outside is moderate- between 55F and 75F.
-Roads are smooth
-Moderate use of the HVAC system
-Combining short trips into a single trip- so that the engine doesn't cool down.
-Wind direction is at the vehicle's back (or low wind conditions)
-Proper tire pressure

Things that will significantly reduce MPG:
-Heavy use of the heat in winter or the A/C in summer
-Heavy acceleration and strong braking
-Lots of short trips where the gas engine has a chance to cool down.
-Low tire pressure
-Driving in snow and cold weather
-Driving into heavy wind / strong wind resistance
-A full load of cargo or having seven or eight people on board (extra weight = lower efficiency)

The hybrid system is most efficient when the vehicle's gas engine is warmed up to normal operating temperature, the vehicle is driven conservatively (no strong acceleration or sudden and strong braking), and the outside temperature is moderate so that the HVAC system doesn't have to work very hard to heat/cool the cabin.

Purchase / Purchase Again?
I really wanted a Highlander Hybrid Platinum- but those are extremely hard-to-find and generally fetch top dollar- both in terms of new and used. I ended up settling for the gas version- but would have bought the hybrid if I could have gotten one. They are excellent vehicles that hold their value really well over the first few years of ownership. As they get older (10+ years), the resale value starts to fall pretty drastically as the potential of battery replacement becomes more of a concern. I was able to get my non-hybrid Highlander Platinum for $3000ish off MSRP last year. No such discount existed for the rare Highlander Hybrid Platinum that appeared from time-to-time on my local dealer's lot- those were always sold for MSRP- so not only would it have cost me $3000 more in terms of that discount- but the hybrid is also about $1500 more than the non-hybrid Highlander- so it would have been roughly $4500 more expensive for me to go with the hybrid- if I could have found one.

There's certainly a demand for Highlander Hybrids- which speaks volumes about the whole "would you buy it again" question. Sales don't lie.

 

We love our 2021 Highlander Hybrid Platinum. Zero issues. Only one slight disagreement with the points above is I see no reason using the heater itself would significantly reduce MPG. However, winter does due to thicker fluids, longer warm-up times, stiffer tires, etc. Well, possibly using the heater in city driving would be a penalty, as the engine would need to run more often to keep the coolant hot, but with highway operation, winter or summer, rarely does the ICU quiesce.

YES, contrary to naysayers, and per the CarCareNut, oil changes every 6 months or 5K miles, whichever occurs first.

The Toyota hybrid "transmission" is simplicity incorporated. No clutches, brakes, or solenoids. Essentially two electric motors and a planetary gearset (referred to by Toyota as a Power Split Device). No engine belts, actually no belts, period. No starter or alternator to fail.

 

39 MPG in Eco mode, mileage 30K, no issues, add gas and change the oil!

 

Had a 2020 V6 gas Platinum now a 2023 I4 HiHy Platinum. Prefer the hybrid version for faster takeoff, CVT's smoother acceleration and better mileage 19 gas vs. 34 hybrid.

More interior noise with the hybrid's I4 and poorer response in tight or high speed turns because hybrid's independent transaxles lack the gas version torque vector steering.

 

Mileage
During the spring, summer, fall months I average ~ 35 MPG. Lowest I had in the summer was 33 MPG - was using the A/C a lot. Winter months I'd average ~ 32 MPG. The best I've gotten has been 36 MPG, the worst has been 31MPG.

Reliability
100% uptime over the last 3.25 years of ownership. Had no issues.

Maintenance
Regular changing oil & filter every 5K miles, cleaned the battery fan filters at 20K miles as well as cabin air filter. That is all that needed to be done.

Total mileage to date is ~24K miles.

Additional information
I have experienced the braking issue when one steps on the brake and the car does not slow down immediately. There is a thread in this forum about this.

The transmission 'growls' noticeably when doing hard accelerations.
Interior noise level is fairly low, e.g. quiet

Annoyances
The wireless phone charger is underpowered/worthless.
The stock Bridgestone tires won't make it to 30K miles.
The front passenger seat is only 4 way adjustable
The lowest fan setting in A/C is still noticeable enough that cold air blowing from the center ducts on the dash lands on my arm and is uncomfortable - would be nice to be able to completely shut off the air flow.
3rd row rear seat is only for kids

Final thoughts
I really like the vehicle. Getting 35 MPG for a large vehicle that is quiet is exactly what I wanted and it works well in this regard. I also got the extended 10 year warranty as I do plan on keeping it and there is enough electronic wizardry that could go wrong, and replacement is usually expensive.

 

How often do y'all replace water pumps on the hybrid Highlander? Read somewhere it's suggested at 100k miles but that also probably depends on type of miles one drives.

 

My last car was a v6 HL and WP failed at 120K or so. This makes me think that 100K suggestion is reasonable.

 

Reliability:
For me personally with a 2021 XLE AWD Hybrid (bought used) has been good. Nothing needed repair so far, but there is a strange suspension related knocking coming from the back that I can't figure out. It happens when going over dips or bumps while turning, sounds as if spring was sliding or something else shifting and not being fully tightened. rear-door power struts are known to fail.

Maintenance:
Excellent. While complicated due to the hybrid setup, the maintenance is simple and is easy to do. This is where I think Toyota makes a lot of sense and why i like it. Basics is easy and reliability of Toyota hopefully means we won't need to do anything complex.

Mileage:
Fluctuates, but generally good. In town while easy on the gas and with hills and traffic stops - 31mpg on average.

On highway or on flat terrain - as high as 40mpg for some. I just had a 2.5 hour trip, including some mountain driving that resulted in 38mpg (according to the car computer), probably a bit less in reality. However, this is inconsistent and is very driving style and terrain dependent.

Purchase / Purchase Again?
No. I'm really disappointed with the quality of materials and assembly. Compared to my old highlander, this one feels like a lifted corolla - a noisy plastic econobox. It does a few things really well - MPG, reliability. But misses in so many other ways

• terrible seats. I get back pain in 20-30 minutes. Lumbar support is horrible - it pushes in one specific spot into your back creating a single pressure point. Seats are thin and not supportive, poorly shaped.
• materials - all surfaces are very plastic-y, thin and resonate a lot.
• noise - There is not much sound deadening. Some in floor, but the doors are empty. Door cards flex and creak, door lock buttons vibrate and rattle. Cross wind noise is very noticeable. hybrid engine is a bit buzzy under moderate to heavy acceleration. Same for downhill driving when it uses it for engine-braking.
• rear-door power struts are known to fail
• navi/infotainment system is a source of a lot of complaints. Pre-2023 (i think) is ugly, but at least it doesn't display Toyota services ads at random.
• suspension is super soft. I bottomed out the shocks on a road that had a dip where even lexus IS350 didn't bottom out.
• the old and low capacity battery tech means that you can't go far or fast on battery alone. EV mode is just for moving a car from one spot to another without starting the engine, otherwise it runs at odd times even with battery is fully charged.

It's a good fuel efficient hybrid, but it's not a very refined car. I'm now thinking that I should have given less priority to the MPG and just gotten a car with better materials, interior assembly quality, noise levels and driving experience. Of course that car would have other issues (lower MPG, probably higher maintenance costs, etc).