Service function guideParasitic Drain Test

This guide covers the complete parasitic drain test procedure for tracing a battery that goes flat while the vehicle sits parked, from initial customer interview through current measurement, fuse isolation, and repair verification. It is written for working mechanics and experienced DIYers who already understand basic electrical measurement and have access to a digital multimeter with a current clamp or series current capability. By the end, the reader will be able to set up a stable measurement without waking modules, isolate the offending circuit through systematic fuse and component testing, and confirm the repair with a repeat measurement. The guide also covers vehicle-type differences, common mistakes that ruin the measurement, and aftercare steps that prevent a comeback.