My near 10-years old Honda Jazz (Mk3) has "auto idle stop", one of those rather pointless ways to improve fuel consumption figures by stopping the engine when the brake pedal has been pressed and the car has come to a halt. It automatically restarts when the pedal is released. It worked ok for around four years, only intermittently worked over the next year, and five years ago stopped working completely. The dash display usually stated "Low battery", "A/C on", or the amazingly informative "Not available".
It didn't bother me as I rarely drive in heavy stop-start traffic. About four months ago I had to get a new battery, but the auto idle stop still didn't work. Last week in the extreme heat, with the A/C on continuously, I pulled up at a roundabout and the engine stopped with the "idle-stop" symbol showing on the dash display! It has continued to work perfectly ever since.
Cars!