Check Hybrid System, P0A78, cost?

It sounds like an unfortunate situation for you. I don't know the rules for the hybrid warranty and second/third owners, but perhaps the best way to find out if it's covered under a warranty is to get it checked at a reliable dealership?

I know one thing for certain, if parts get messed with and opened up/replaced and then you get it checked at a dealership, it definitely will not be covered.

 

Here's a copy of the 2013 warranty book. Page 14 says inverter in covered.

 

On a 2013 Prius c, code P0A78 should be reported only with one or more three-digit INF (information) codes. If your scan tool can’t read INF codes, you’ll need to scan the car again with one that does, such as a Toyota Techstream diagnostic system, or just take it to a Toyota dealer for diagnosis. @TMR-JWAP gives sound advice about not attempting your own repairs before seeking warranty service.

The Warranty & Maintenance Guide says, “Warranty coverage is automatically transferred at no cost to subsequent vehicle owners,” so don’t worry that you bought the car used, as long as it’s within the time and mileage limits for hybrid system warranty coverage.

It’s hard to offer more specific advice without knowing which INF codes your car has reported.

Toyota’s Repair Manual, available by subscription to techinfo.toyota.com and from the ChiltonLibrary service, to which your local public library sponsors free access for its patrons, gives detection conditions and troubleshooting procedures for each INF code. For some INF codes, the trouble is likely to be in the inverter with converter assembly, but for others, the manual says the trouble could be elsewhere:

• Cooling fan system
• Frame wire
• Hybrid battery junction block assembly
• Hybrid vehicle transaxle assembly
• Inverter cooling system
• Inverter with converter assembly
• Motor cable
• PCU fuse
• Power management control ECU
• Service plug grip (EV battery fuse)
• Wire harness or connector

As @TMR-JWAP kindly mentions, the hybrid system warranty covers some of the more expensive parts, like the inverter and transaxle assemblies, and the labor to replace them.

 

iirc, another member with that warning just needed a cooling fan cleaning. or maybe just a clogged intake grille, i forget.

 

please let us know the outcome, all the best.