Inverter Coolant Valve ID

There is no valve associated with the inverter coolant system. There is a valve associated with the engine coolant system but that is unrelated to the issue your car has.

 

That person is preying on your ignorance to sell you something that's not needed.

A defective 3-way coolant control valve will trigger a CEL (Check Engine Light) and trigger DTC P1121. This valve will NOT leave you stranded. It can prevent the cabin heater core from receiving hot engine coolant to have a warm cabin interior and prevent the vehicle from passing emission test due to the CEL.

 

Just to be accurate, if the 3-way coolant control valve was leaking, that could become a major issue and leave you stranded. Also, this valve is a known failure item; it will require replacement at some point in the future.

However, I do not recall reading any OEM 3-way valves leaking when P1121 is triggered. OEM vavles seem to just get stuck in the wrong position, thus the need to replace, as the valve motor has likely worn out.

I have read of aftermarket 3-way coolant control valves leaking, after a very short period of use.

If you can afford it, best to stick w/ OEM parts. A few dollars more, but superior construction and longevity!

DAMN! Just noticed the highway robbery on the invoice.
All dealerships and service shops (National chains and independent) seem to ALWAYS want to upsell everyone on the need for "chemical cleaning" and/or "chemical conditioning" of the coolant. These additives are a HIGH profit item. It is equivalent to fountain sodas at fastfood/full-service restaurants. If you have followed the factory service interval for drain and fill of the engine and inverter cooling loops, you will be fine; you can always perform the drain/fill at a more aggressive (sooner) pace if you want, but not later.

FCUK (French Connection United Kingdom) their $30-1gallon coolant! It is probably some "universal" all vehicle coolant, which really means it is for NO modern vehicle made today!
Insist on Toyota SLLC ($16.95/gallon last time I had to buy it). Or 2nd best would be aftermarket coolants that state they are manufacture specific: Prestone, AISIN. Many times, cost difference between aftermaket-Toyota coolant vs Toyota SLLC is very small.

Read these two articles about coolant:
Can you use universal coolant? — Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice | Automotive Repair Tips and How-To
Universal Coolants: The Ultimate Answer?

 

Anytime your vehicle is on a rack at a dealership or indy, is an opportunity for them to go shopping at your expense. Do as the OP did here and question their quote whether on a vehicle specific forum such as this or with other trusted sources.