Service function guideHybrid Inverter Cooling Service

This guide provides a complete, professional procedure for servicing the inverter cooling system on hybrid and electric vehicles, written for working mechanics and experienced DIYers who already understand high-voltage safety fundamentals. It explains how the separate low-temperature cooling loop protects the power control unit, when a service is actually required, and how to prepare a bay so the job proceeds without coolant contamination or electrical risk. You will be able to drain, flush, refill and bleed the inverter circuit, verify pump and thermostat operation with scan-tool data, and diagnose the airlocks and flow faults that cause power derating. The guide also covers differences between series, parallel and plug-in architectures, the mistakes that destroy pumps and inverters, and the aftercare checks that confirm the repair holds under load.