I had a local shop replace my rear brakes recently and now my auto start / stop feature has stopped working. I took my battery to AutoZone and they verified that my battery is in good condition. I’ve read that the brake lines not having sufficient vacuum could cause auto start / stop to stop working. I dread having to go to the dealer. Should I replace my battery to see if it fixes it? I have a 2020 Ranger with about 100k miles. It may be time to replace anyway as I still have the original installed.

 

Unless there has been dead battery issues in the past a 2020 battery should be good until 2025-2026, 5 to 6 years usually
But yes, low battery voltage would cause Auto stop/start to not stop engine

Auto/stop start only works after engine has warmed up, and if Defrost is off, and if cabin temp has warmed up or cooled down enough, depending on the season
Yes, vacuum leak in power brake booster could cause Auto stop/start to not shut off the engine, but changing brake pads wouldn't/shouldn't effect Booster

Ford service explanation for Auto stop/start: https://www.fordservicecontent.com/F...&buildtype=web

Google: How to Permanently Disable Ford Ranger Auto Start/Stop in 60 sec or less! No special tools required!

Not to disable yours, but maybe this is why yours is not working, the plugin on the Battery negative cable is disconnected or wires are loose, worth a look