Cause
Faulty inverter coolant pump
The electric pump circulating coolant through the power electronics' own low-temperature loop — a separate system from the engine's cooling, with its own reservoir and often its own small radiator, because inverters must be kept far cooler than an engine runs.
When it stops, the inverter overheats while the engine's temperature gauge reads perfectly normal — the misdirection this part is built around. An electric pump also fails silently: no belt to squeal, no visible leak required, just an inverter that derates or cuts drive on warm days and recovers after cooling. Checking that the pump actually runs, and that the loop's reservoir is full and free of air, is a five-minute job that resolves a disproportionate share of inverter over-temperature and performance codes.
Typically specialist work. Needs equipment or training most home workshops do not have.
Codes this can cause (73)
Codes where this is a likely explanation first, rather than merely a possible one.
- P0A05 Motor Electronics Coolant Pump A Control Circuit/Open Likely for this code High
- P0A06 Motor Electronics Coolant Pump A Control Circuit Low Likely for this code High
- P0A07 Motor Electronics Coolant Pump A Control Circuit High Likely for this code High
- P0A3C Drive Motor A Inverter Over Temperature Likely for this code High
- P0A3D Drive Motor B Inverter Over Temperature Likely for this code High
- P0A3E Generator Inverter Over Temperature Likely for this code High
- P0A78 Drive Motor A Inverter Performance Likely for this code High
- P0A79 Drive Motor B Inverter Performance Likely for this code High
- P0A7A Generator Inverter Performance Likely for this code High
- P0A7C Motor Electronics Over Temperature Likely for this code High
- P0A93 Inverter A Cooling System Performance Likely for this code High
- P0AF7 14 Volt Power Module Internal Temperature Too High Likely for this code High
- P0B38 Motor Electronics Coolant Pump B Control Circuit/Open Likely for this code High
- P0B39 Motor Electronics Coolant Pump B Control Circuit Low Likely for this code High
- P0B3A Motor Electronics Coolant Pump B Control Circuit High Likely for this code High
- P0C31 Inverter B Cooling System Performance Likely for this code High
- P0C73 Motor Electronics Coolant Pump A Control Performance Likely for this code High
- P0C74 Motor Electronics Coolant Pump B Control Performance Likely for this code High
- P0CE9 Hybrid/EV Electronics Coolant Pump A Control Circuit/Open Likely for this code High
- P0CEA Hybrid/EV Electronics Coolant Pump A Performance Likely for this code High
- P0CEB Hybrid/EV Electronics Coolant Pump A Control Circuit Low Likely for this code Moderate
- P0CEC Hybrid/EV Electronics Coolant Pump A Control Circuit High Likely for this code Moderate
- P0CED Hybrid/EV Electronics Coolant Pump A Enable Circuit Likely for this code High
- P0D24 Battery Charger A Temperature Too High Likely for this code High
- P0D32 DC/DC Converter A Over Temperature Likely for this code High
Information, not instruction
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