Parasitic battery drains

CORE TEACHING Normal sleep current; sleep delay; door/bonnet latching; key proximity; current clamp vs series meter; module wake cycles; fuse-drop method. PRACTICAL DEMONSTRATIONS AND TESTS Latch doors; lock car; move key away; monitor current over time; isolate fuses/branches without constantly waking car. ADVANCED / SCAN TOOL LAYER CAN/network activity scope/logging; scan last-wake reasons if available; fuse mV measurements. KEY DIAGNOSTIC QUESTIONS Has the car actually gone to sleep? What wakes it? Is the current constant or cyclical? MUST-COVER CHECKPOINTS Prove battery/charging first; prepare vehicle for sleep; establish current timeline; identify wake pattern; branch isolation; network effect; final component proof.

Locked vehicle appears asleep, then current jumps every few minutes and kills the battery overnight.

Builds on

Lesson 52: Finding shorts to positive and back-feeds

Feeds into

Lesson 54: When pulling one fuse kills the drain

1. 47Power–ground–signal: the default framework
2. 48Test the connector before replacing the component
3. 49Loaded circuit testing
4. 50Finding open circuits
5. 51Finding shorts to ground
6. 52Finding shorts to positive and back-feeds
7. 53Parasitic battery drains
8. 54When pulling one fuse kills the drain
9. 55ECUs and control modules
10. 56The complete Voltzs diagnostic workflow