Short answer: P0A93 reports that the inverter cooling system is not performing as expected — usually a failing coolant pump, a blocked duct or low coolant, not the inverter itself. It is not a battery code, and replacing the pack will not fix it.
What you see on the dash
Red triangle, “Check Hybrid System”, reduced power; in severe cases the car limits output to protect the inverter.
What the code actually means
The inverter generates heat under load and depends on its coolant circuit. When temperature or pump behaviour falls outside the expected range the controller logs P0A93 and derates the vehicle.
Likely causes, in order
- A tired or seized inverter coolant pump (the usual culprit).
- Low coolant level or air in the circuit after a repair.
- A blocked radiator, duct or grille.
- A temperature sensor reading incorrectly.
How to test before you buy anything
- Check coolant level and look for leaks.
- Command the coolant pump with a scan tool and listen for it running.
- Check pump speed and inverter temperature live data.
- Inspect the radiator and ducting for blockage.
Repair or replace?
Fix the cooling circuit — pump, coolant, airflow. Only if the inverter itself has overheated and failed does the inverter need replacing, and even then the battery is not involved.
Frequently asked questions
Is P0A93 a battery fault?
No. It is an inverter cooling fault; the high-voltage battery is not part of the circuit being reported.
Can I drive with P0A93?
Short distances at low load, but the car will derate and continued overheating can damage the inverter.
Why does the car lose power with P0A93?
The controller deliberately limits output to protect the inverter from heat damage.
Need a pack for this code?
We supply brand-new Ni-MH and Li-ion replacement packs for Toyota, Lexus, Honda and GM hybrids — 144 V to 288 V, with a capacity and resistance report for every unit. Browse packs by vehicle or send us the VIN and the scan and we will confirm fitment before you order.
Codes can have more than one cause. This page is a diagnostic starting point, not a substitute for testing the vehicle.