Fixing a Ford Focus/CMax's auto-start/stop system - it's all in the battery!
This foxed me for ages. And I'm hoping that relating the tale will help someone else. We have a Ford CMax (2015), but the same systems apply for the Ford Focus, on which the CMax is based. We bought it in 2018 and the auto-stop-start system worked fine for a couple of years. As a reminder, this auto-stops the engine when stationary in traffic and when the handbrake is on (and gear in neutral, obviously). Then, when you engage a gear and release the handbrake, the engine is auto-started and you're off. A nice fuel-saving measure, in theory. Alas, around 2020, the auto-stop-start system ceased to work. The green 'A' above was greyed out and with no explanation. Research online pointed to this system not working in very cold or hot weather, or when the engine's not warmed up enough, or if you have all the lights and wipers on. Sensible reasons. But not applicable in our case - it remained a mystery. There was a clue in that 'low battery state' was also listed,