P0A93

P0A93 indicates the inverter cooling system is not performing to spec — specifically, the inverter coolant temperature is climbing faster than the BECM's thermal model predicts given commanded pump speed and ambient conditions, or the temperature is exceeding the high-side threshold (65C on Prius, 70C on Ford eCVT) during normal operation. Cheapest-first diagnostic ladder: visually check the inverter coolant reservoir level FIRST — this is separate from the engine cooling system on Prius/Camry Hybrid/Highlander Hybrid and shares with engine coolant on Ford Escape/Fusion Hybrid; Toyota's inverter loop uses pink Toyota Super Long Life. Listen for the electric inverter coolant pump (Toyota P/N G9020-47031 is the famous Prius part) running with key-on engine-off — you should hear a quiet whirr from the pump for 30-60 seconds; silence means a failed pump, which is the #1 cause of P0A93 on Prius Gen 2/3. Caveat: P0A93 on Prius Gen 2 with original-mileage coolant pump should be assumed to be the pump until proven otherwise — the failure rate is so high that Toyota issued TSB EG024-11.

Vehicle-specific patterns: 2004-2009 Toyota Prius Gen 2 (NHW20) — inverter coolant pump (G9020-47031) failure at 100K-150K miles is so common that the aftermarket sells a $90 OE-spec replacement. 2010-2015 Toyota Prius Gen 3 (ZVW30) — revised pump P/N G9020-47030 still fails but at higher mileage. 2007-2011 Toyota Camry Hybrid / Highlander Hybrid — shared inverter pump architecture, same failure mode. 2013-2018 Ford Fusion Hybrid / C-Max — inverter coolant loop shares with engine loop, P0A93 often caused by a stuck-closed thermostat. Estimated repair: $180 to $850.