نشت مایع خنک‌کننده داخل پک باتری

Liquid coolant escaping inside a traction battery enclosure — from a cracked cooling plate, a perished hose, or a fitting that has worked loose with vibration and thermal cycling.

It announces itself as implausible sensor readings long before it announces itself as anything dramatic. Coolant reaching cell-voltage sense wiring creates paths that were never designed to exist, so voltages and temperatures start reporting values the battery module rejects — which is why a leak is often found through a network fault rather than a puddle.

Take it seriously and do not defer it. A high-voltage pack with liquid inside is one of the few faults on an electrified vehicle that does not stay small, and an isolation warning alongside this is a reason to stop rather than to book an appointment.

Diagnosis and repair are for a qualified high-voltage technician. The pack is not something to open, and coolant level in the battery circuit — which is usually separate from the engine's — is the one check an owner can usefully report.