سنسور پایش باتری معیوب

The sensor on the battery's negative terminal measuring current, voltage and temperature, faulty so the module cannot judge the battery's state. It is how a modern vehicle knows what charge the battery holds, and everything the charging strategy does depends on it.

A wrong reading produces charging that is wrong in a plausible way. Believing the battery is fuller than it is, the module undercharges and the battery slowly dies; believing it emptier, it overcharges and boils it. Neither presents as a charging fault — the alternator works, the voltage looks reasonable, and the battery simply fails early.

It also governs stop-start, so a vehicle whose stop-start has quietly stopped working often has this rather than a battery problem. The sensor is on the earth lead itself, so its connection is a heavy current joint that corrodes, and disturbing the terminal disturbs the sensor. A new battery must be registered on these systems; skipping it leaves the module charging to the wrong profile with a healthy sensor.