2008 inverter coolant pump

Your inverter pump has failed. Next time the warning light comes on, check if the ac still works. When the failure occurs, it often disables the ac cooling.

Also check your oil level as the car will use oil. Add as needed

SM-N900P ?

 

An easy test is to look for turbulence in the coolant in the plastic reservoir attached to the inverter (large silver cover on driver's side under hood). Put the car in IG-ON mode (push power button twice, foot off brake), take cover off reservoir, shine flashlight in, you should see the pink fluid moving slightly. You should also be able to hear an aquarium pump-like sound from just behind the left headlight.

 

Other than what has already been suggested you could verify the electrical connector to the pump is securely attached and not compromised from the PO.

If it is your inverter pump, and fwiw I tend to agree with the previous diagnosis, its an pretty easy R&R. I just did mine as a preventative measure when I changed my inverter coolant two weeks ago. These are common failure part on this generation Pri. And if you don't have the service history of when the inverter coolant was lasted changed I'd encourage you to add that to your service list at the next opportunity.

 

The pump cools the car's inverter. When you drive the car, it heats up and the AC will stop working and warning lights come on. When the car is off, it'll cool and things might go back to normal, the AC will work again and the warning lights will go off. This repeats itself whenever the car overheats.

As you've stated, it happens after you drive for a while. It doesn't start right when you first get in your car.

 

Check the pump just like andrewclaus has outlined above, either by looking in the reservoir for fluid turbulence OR try finding the pump and touch the plastic housing to check for vibration (assuming you can't already hear it), neither is fool proof and if the pump has never been changed before now could be a good time.

Which state was the vehicle originally purchased in and is the vehicle under warranty?

You should contact the dealer (over the phone or in person) and inquire about outstanding recalls that you may qualify for, some might even be related to your issue: http://media.fixed-ops.com/Toy_Campaigns/c0u-dlr.pdf

You can always check dealer service records with your VIN if you are unsure about previous dealer related repairs having been performed or not.

 

The pumps usually go for about 100k miles and they can start developing issues. Check the mileage since the recall.

You are still not certain it's the pump, so if you decide to replace it, make sure it has about 100k miles on it. Just in case it's something else, you can treat this as preventive maintenance for the pump

SM-N900P ?

 

Well, "easy" or "hard" depends upon your level of wrenching skills. Maybe my post here will help you decide whether you can DIY or not.
How to Replace the Inverter Coolant Pump | PriusChat