We often make fun of them: Techs who use the scan tool to tell them what part to replace. We must admit that sometimes, for the sake of expediency, we do the same thing. Let’s not get caught in that trap on a Toyota with a lean condition.
The Prius uses an independent cooling system to cool the inverter and Motor/Generator. In warm weather, problems with the inverter cooling system are fairly common in both the Gen 1 Prius (2001-2003), and Gen 2 Prius (2004-2009).