Inverter "A" Cooling System Performance
The P0A93 code means the vehicle's onboard diagnostic system has detected: Inverter "A" Cooling System Performance. This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $900 (coolant service or pump at the low end; radiator/heat-exchanger work at the high end)
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Common Symptoms
- Check Engine Light on
- Inverter temperatures climbing under load
- Reduced power as the system derates to shed heat
- Overtemperature codes follow if unaddressed
Probable Causes (Ranked by Likelihood)
- Low coolant in the inverter (power electronics) loop High
- Failed or airlocked inverter coolant pump High
- Blocked inverter radiator or heat exchanger Moderate
- Coolant temperature sensor fault Low
Frequently Asked Questions
What does P0A93 mean?
P0A93 means the Inverter "A" Cooling System is not keeping the inverter at its expected temperature - flow, coolant level, or heat rejection is inadequate.
Can I keep driving with P0A93?
Short, gentle trips only. The inverter derates to protect itself, but sustained heat kills power electronics, and the usual fixes (coolant, pump, bleeding) are cheap by comparison.
Is P0A93 safe to work on myself?
This code involves the high-voltage system. Do not open the HV battery, inverter, or any orange-cabled component without hybrid-specific training, insulated gloves, and the service plug removed. Diagnosis beyond a scan-tool read belongs at a hybrid-qualified shop.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Check the inverter cooling loop's own reservoir - on most hybrids it is separate from the engine's.
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Confirm the electric coolant pump runs and actually circulates (watch for flow in the reservoir).
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Bleed air from the loop per the OEM procedure - airlocks after coolant work are the classic cause.
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Inspect the inverter radiator for blockage or debris.
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Monitor inverter temperatures on a road test after repair.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Commonly Affected Vehicles
- Toyota/Lexus hybrids (Prius, Camry Hybrid, RAV4 Hybrid)
- Ford/Lincoln hybrids (Escape, Fusion, C-MAX)
- Honda hybrids (Insight, Civic Hybrid, Accord Hybrid)
- Hyundai/Kia hybrids and plug-in hybrids
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