Is inverter pump always on?

This is a separate sorta' questions
I think I have an inverter coolant pump failure
second one-first happened at 55000 miles-now at 111,000 miles
Three signals RED TRIANGLE CHECK ENGINE AND CAR WITH EXCLAMATION POINT
Car still runs fine-made it home
I read that if you hit START twice-no brake
then a functional pump should be ON
and it should vibrate enough to vibrate the RESERVOIR HOSE-and reaching down-should be able to feel it vibrate
I have NO vibration
and with ICE on-still no pump or reservoir hose vibration
Is this correct-the pump is on as soon as vehicle ignition is on
or as soon as ICE on?
No turbulence in reservoir also
Thanks
Charlie
ps great forum-I always head here for Prius problems-just in 11 years counting this one
traction battery failure and 1st coolant pump fail

 

Patrick-thanks again-pretty sure you helped me before-
I did the double push on start-no brake pedal
No vibration on hose or on actual pump
The plastic shroud lifts up easily-since half the clips weren't reinstalled after perhaps the first pump was replaced
Yeah dead silent no vibrations dead as a doornail
Thanks again-debating DIY or dealer
DIY with bought at dealer pump-maybe $180
Dealer probably $700-and fighting off their attempts to sell me something else
but they will do it "better"
and I won't be near any 25000 watt wires
Thanks
Charlie

 

M in KC
Patrick W-
Thanks-yes it was the inverter-and yep Patricks info is always spot on

I went with the dealer-$440 total-not bad at all
Originally they-Lakeside Toyota- quoted $560+ Tax-$610
but it was $440 Total

My 31 yo son needed it for a date he has Thursday-and I would have bought the pump online for $110 or so-and it wouldn't have arrived until Thursday-
And Murphy's Law-always fully in effect the 1st time I do a repair replace
much less now that I'm older-66-and weaker and more careful-but learning curve and Murphy-
always a consideration
and I wanted my son to cough up the $$-motivate him to be more aware of $$ maintenance etc-
not rely on dad-
but mostly Murphy and Learning curve and time considerations
If the difference had been $600 vs $300 I would have DIY
but just $300 -let pros do it-had good luck with Lakeside Toyota Causeway Blvd Metairie( give credit to good dealers-to OK repairs-and a clutch replacement 1986 Toyota truck in 1994) also so 3 good repairs-no problems-fair price

It was the Inverter coolant pump-AGAIN-1st failed at 60,000 miles 51,000 miles and 6 years ago
I debated DIY vs Dealer
I had Lakeside Toyota do it-$440 all total $250 labor $127 pump-$20 coolant-$40 tax
VS getting it from Amazon-$110 and 3 days to arrive
With Murphy's Law fully in effect-meaning some chance
1)I would break something doing the repair-1st time doing repair-fair chance it would go wrong
2) some chance it would be thw WRONG REPAIR-no vibration and no turbulence in reservoir-so small chance
3) tiny chance one of the fasteners would break-or be too difficult to remove

'All in All I decided to pay another $320 to have Lakeside do it-same day brought in
Lakeside did the Traction battery replacement-under warranty-no BS extras
and true to form-not much pressure to get other repairs(some but low key-no it will break and kill you stuff)

Thanks again-great source of great info
Charlie