Is coolant control valve part of Engine Cooling System, or Inverter Cooling System?

1) Engine loop.
2) If they did not charge you for it, then they did not perform an Inverter loop drain/fill.
3) They should have simply drained the engine loop when replacing the engine water pump and 3-way coolant control valve. However, it would NOT surprise me if they removed the water pump and pinched off the hoses on the 3-way valve.

Just bite,the bullet and do a drain/fill for both loops. The amortized cost over the next 5years will be minimal.

If you DIY, the cost of drain/fill both loops will be low.

It should be a drain/fill. No flushing!

 

Exactly! What did the dealer charge you for? They don’t forget to charge for everything they can. Even paper towels and hand cleaner are charged as “shop supplies”.

 

Ouch. Do you have any mechanical skills? The inverter isn’t that hard to do yourself. The engine cooling system is a little harder but to save 250 bucks I would do some homework.

 

100% GUARANTEE YOU, $32 charge for coolant = top off lost coolant when the water pump and 3-way coolant control valve was replaced. Here's why:

The two times I drained/filled the engine loop, just under two gallons of Toyota SLLC was required to completely replenish the engine loop. The inverter loop is about .75gal BTW, for a drain&fill.
The last time I purchased Toyota SLLC, it was $16.95/gallon; the cheapest price I found at a nearby dealership. $16.95x2=$33.90
I see your $32 coolant charge = 1gallon of coolant they charged you, kept the rest for use on the next customer.
Since you PAID for dealer rates for labor and parts, GUARANTEE you they did NOT do you any favors to save you money!
I do NOT see them giving you the sale price for two gallons of Toyota SLLC ($33.90 I paid).
I do see them doubling the retail price of one gallon of Toyota SLLC ($32 you paid).​

"Drain and Fill" is listed in the factory service manual and the owners manual.

MARKETING:
"Drain and Fill" vs "Flushing"

Flushing will sound more thorough, even to someone who knows nothing about cars.
Flushing can easily be pitched as a higher level of service: better for your car.
Because it is better and "more complicated," they will charge you for "flushing," even though they don't do "flushing."​

used car vs factory CPO (Certified Pre-Owned) vehicle

You pay a premium for that "CPO" feeling.
A used car is a used car period.
A used car may have remaining factory warranty.
A CPO might give you a slight longer warranty than a used car, but you are paying for it with a higher vehicle purchase price; NO FREE LUNCH.
​

Try contacting @3prongpaul. He is a member here who works at a Hybrid shop in Boulder, CO. Maybe they have normal rates for normal people. I can't comment on the quality of their work, as I DIY. But, Paul appears to be very knowledgeable.