2010 Prius with a Hybrid Inverter system failure

Here is some updates on this problem from my side. Our Prius was originally sold in PA and then was relocated in VA. This is regarding weather only CA Priuses are affected by ZE3 warranty enhancement. Back in Jan 2021 we did a recall related to inverter software update. And couple of weeks ago (Mar 2022) our inverter went bad and car went to limb mode. Scanner showed error codes P0A94 and P0A7A.



Clearing those codes clearly did not help, errors were coming back immediately. So we did some research online and stumble on this thread. After reading about ZE3 warranty enhancement we took our car to local Toyota dealer for diagnostics. Dealer did confirm the problem with the inverter. I did mention the ZE3 enhancement to them and they told me that they will contact Toyota NA to get the green light on this repair. After 3 days waiting I got contacted by their manager and was told that Toyota approved this repair. After another 4 days waiting for parts to arrive and actual replacement we picked up our car. The problem is fixed and the car is back on the road. The only thing is when I spoke with dealership manager, he told me that they are going to order brand new unit, but when we picked up our car I saw that the inverter is the same and they were opening it (I saw some silicone around the edges of inverter). Service manager told me that they only replaced IPM transistor on it. He said that some Priuses are getting completely brand new inverters and some are just getting the IPM resistors replaced, but he didn't mention on how they determine which one is getting which (age, mileage, condition of inverter etc.)
He also told me that the there will be 12mo /12k mi warranty on workmanship as well as ZE3 warranty enhancement is still in place till 2025 (15 years from manufacturing date) with no mileage limitations. Based on a sticker in our Prius it was manufactured in June 2010 and the mileage when repair was done was around 192k. We didn't pay anything, all repairs and diagnostic expenses were coved by Toyota.



So for those who are having similar issues with their Prius, definitely worth to take your car to your local Toyota dealer before trying to fix it yourself.

 

There are a few different bits and pieces inside there: the IPM, the MG ECU, the converter, the current sensor ....

Depending on what codes you have and what was damaged, they replace one or more of those. They start by looking right at the outside of the aluminum case to see if the failure physically damaged it (on the inboard side, near where the big multiwire connector attaches). If that happened, you get a whole new shiny inverter assembly.

The IPM is the biggest hunk of gear inside there; it includes the six transistors for each of the two motor generators, and all their supporting circuitry, and the water-cooling heat sink; the coolant hoses you see running to the inverter attach to the hose nipples of the IPM.