بطارية 12 فولت متدهورة

The small conventional battery every hybrid still carries — and the cheapest, most frequently guilty part in the whole hybrid range. It does not crank anything, so it never announces its decline with slow cranking the way a conventional car's does; it just quietly fails to hold voltage, and everything that depends on stable twelve-volt supply starts reporting faults that are not theirs. Contactors that cannot pull in (a car that will not wake, on a perfect pack), modules failing self-checks, a dozen warning lamps at once — the spectacular display of a flat twelve-volt battery on a healthy hybrid is one of the corpus's most repeated stories, from U0111 to the contactor family.

Test it first, always: it is the one component on this page diagnosable in five minutes with a multimeter, and replacing it resolves an outsized share of frightening-looking hybrid complaints.