freman dave

Mine doesn't put any messages on the dash but just randomly works from time to time. No changes to HVAC controls, etc. Some days it works, most days it doesn't. I hope it decides to quit working completely.

katoom

Been having this issue with mine since Jan and it's completely intermittent. The one time I took it to dealer to have it checked it was not having any issues and battery tested fine.

Next day it quit working, I really like the feature so I'd love to know why it's not working anymore.

Lare

I'm beginning to think the computer is doing something more than just battery voltage. I put mine on an intelligent charger last week after it seemed to stop working. At full charge, no auto stop. But the next day (without charging overnight) it was working again . I suspect it could be tied to a variety of parameters.
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Rmuesi

my truck is having the same issue. It was off for a month and a half straight. Nothing I could do would turn it on. Long drives, letting it idle. Then it turned on suddenly one day at a stop light. Wasn't doing anything out of the ordinary. And for a day straight it was turning on at every stop, right away. No hesitation. And then it just stopped. It's been about two weeks now. Hasn't turned on since. Always vechicle charging.

Hctr154

It happens....it will eventually fix itself. Battery has to be at optimal level, if not then the auto stop/start will not work.

Rmuesi

Nah. Battery is fine. Something is broken on it. There's no logical reason it would behave this way. I live in Vegas and the temperatures right now are in the 70s. Perfect weather. No reason it should be off 1.5 months, on 1 day and off another 2 weeks.

RL1990

The F-150 uses a smart charging alternator and a battery management system. It only charges the battery when the PCM commands it to. If there is no high demand for power or the battery is not low the PCM doesn't tell the alternator to charge the battery. Also I think the computer needs so many hours (not sure how many) of uninterrupted module sleep time to get an accurate reading of the battery state of charge. If you take frequent short trips and/or the computer doesn't have an accurate reading of the battery's charge the PCM may detect a low battery and command maximum charging from the alternator. Just like high demand for A/C, the alternator running at max charge would disable the start/stop system.

tmcolegr

Here's some great information on Auto Start-Stop

Saleendude07

Mine quit working for almost a week. I thought I was the luckiest guy with a 2.7. Then it stated again. Not sure what caused it. I drive the truck everyday and almost always take the same route.

rddakota

tmcolegr posted a great PDF which explains all the permissives that have to be met before the feature is activated. Cabin temperature, battery voltage, engine temperature (won't work after a cold start), etc. A list of permissives are also list in the OEM manual.