تشويش من أجهزة إرسال أو ميداليات أخرى

Other transponders or metal on the same keyring disturbing the immobiliser's read. The antenna ring energises the chip inductively and reads a weak reply, so a second transponder in the field replies at the same time and a mass of metal detunes the coupling.

The classic case is two vehicles' keys on one ring, which is common enough to be worth asking about directly. The symptom is intermittent: it starts most days and occasionally does not, which reads as a failing key. Try the key alone, off the ring — an immediate and free test that settles it. A heavy ring also wears the ignition barrel over time, which is a separate fault arriving from the same habit.