Just went past 200k. What do I need, what don't I need?

Other than the initial break-in check, most manuals tell you to continue the mileage/service patterns already specified.

Are you still on the original '04 hybrid battery in Florida?

I just did the transaxle fluid change myself, found it even easier than an oil change, and about the same price in parts as an oil change. If you're not a DIY'er, demand the service. I can't believe they would turn down such easy money.

 

IF (and it does not) the Prius had a torque converter and hydraulic shift points, THEN there can be issues with the new fluid loosening clots that block shifting logic. (like a stroke in the brain) This is a real but overblown problem in 'automatic' transmissions.

The Prius has no torque converter and no hydraulic shift logic, it never shift gears at all when moving. (There is a pawl that electrically shifts position when you put it in P)

 

Correct, no tiny passages to become clogged.

If it WAS an 'automatic' the valve body might look like this: lots of potential clogs



The Famous Valve Body – The heart of the automatic transmissions hydraulic control system is the valve body. It’s considered the hydraulic control center, it receives pressurized fluid from the main pump operated by the fluid coupling torque converter. Are you having an issue shifting into the last gear? When you try to drive your car does it feel like the emergency brake is on? Is there a delay in engagement when placed into gear? These could be signs of a deteriorating valve body

The Prius logic is all electronic, not hydraulic, so the ATF WS is 'just' a lubricant and coolant.

 

My Toyota dealer only argues about how frequently I want the ATF changed, not how to do it. (I prefer 30,000 miles, 90,000 miles and then every 90,000 miles. They advise every 100,000 miles. Here in MS that costs under $100 at the dealer, other locations will have higher overhead costs)

 

My 2005 Prius just hit 216k miles - unfortunately I just had P0A78 + P0A90 error codes.

You have not stated what service you actually performed, so here are suggestions:
replace spark plugs
replace serpentine belt
HV battery is good for about 10yrs max, get ready for it.

Probably others, will let other people chime in.

 

The US maintenance chedule format, being event by event, is completely unhelpful if you're trying to gauge intervals, what's done, and how often. I'd suggest to start a spreadsheet, enter miles/times across the top, and services down the left column. Then go through the schedule, page by page, enter the services as you come to them, and put an X at the appropriate miles/time column. You'll quickly see the patterns, and should be able to extrapolate them, as needed.

 

If you can't tell then there is a problem. Check the fluid level in the radiator by removing the cap. The fluid level should be at the very top and the correct pink Toyota Super Long Life Coolant should have been used. Fill the reservoir to the top line using the correct coolant.

If you find that the correct coolant was not used in the radiator, then that is a problem that should be remedied via drain and refill.

 

Well, that is what happens when you use an independent who does not specialize in Toyota vehicles. If you care, then find out exactly what was put into your car. Then review the spec sheet for that coolant.

If you decide you don't like that coolant, then you could buy a couple of gallons of SLLC and ask for your mechanic to drain and replace.

 

The maintenance prescribed for 100K miles and 120K miles should be done. In particular, replace the iridium spark plugs, engine / inverter coolant replacement, engine/cabin air filters replacement, replace transaxle ATF, inspect engine coolant pump for weeping at the pump bearing and replace if necessary, inspect serpentine drive belt, inspect brakes, suspension and exhaust systems, and repair as needed. You may want to replace the inverter coolant pump as a preventive move - rather than wait for it to fail.

Well, that stupid car has lasted 200K miles and you want it to last another 100K miles so it deserves some attention. It is not a trivial accomplishment for the car to log so many miles.

If you feel that the basic maintenance is too costly that might motivate you to DIY.