اتصال کوتاه عملگر و افت تغذیه

An actuator whose winding has shorted, pulling far more current than its circuit was designed to deliver — and taking its neighbours down with it. The distinctive property is that the fault does not stay where it started: a shared fuse blows, or a supply rail sags, and every device on that rail misbehaves at once.

Which is why a page of unrelated codes can have one cause. Replacing the parts that are merely reporting the symptom fixes nothing, and a fuse replaced without finding the short blows again — sometimes immediately.

The method is disconnection rather than measurement. Unplug devices on the affected circuit one at a time until the supply recovers; the one that restores it is the fault. A shorted winding often measures near enough to normal cold and fails when hot, so a resistance check alone can miss it.