12V Battery Causing Cascade Faults
ModerateElectrics & ElectronicsThe 12V auxiliary battery degrades prematurely, triggering multiple seemingly unrelated high-voltage system errors. A failing 12V battery can make the car refuse to start or enter a fault state.
Typical symptoms
- •Multiple warning lights
- •Car won't start
- •"Electrical system fault" message
- •Infotainment resets
What to inspect before you buy
- ✓Test 12V battery voltage (should be 12.4V+)
- ✓Check service history for 12V battery replacement