Leakage current test (Isolation Test)

Many systems in hybrid vehicles operate using the high-voltage battery. For safety reasons engineers design the system with insulation monitoring against the vehicle body. If even a very small leakage current is detected - sometimes at the microamp level - the vehicle control system may shut down the high-voltage battery and store a fault code. This is done to protect both the vehicle and the driver. However these faults can make diagnostics more complex because the leakage may originate from different components in the system. An isolation test allows technicians to check the insulation condition and locate the source of the current leak.