Some might consider this a blessing but I've had a number of trips over the last few weeks where the *** system in my 2016 2.7 doesn't shut the engine down in situations where I feel like it should or has in the past. At this point, it seems to be entirely random. Coming in to the office this morning it never shut off over the 22 miles. Going home, it may operate as intended.The engine otherwise seems to operate no different than it has for the last 53,000 miles. Smooth and efficient.
I am aware that certain parameters need to be met before the *** kicks in.

 

I've paid attention to mine to figure out some of its logic. Things I've noticed are that the truck has to be warmed up to a certain extent, if there's a high demand on the interior hvac it won't shut off, and if it recently stopped there is a delay before stopping again (such as creeping forward at a light). I've also noticed that you have to have a certain pressure on the brake pedal. You can press the brakes lightly, enough to stop the truck and hold it, but it won't be hard enough to trigger it. That's also a trick if you don't want it to stop. I'm sure it also takes the battery charge into account and won't let it dip very far.

 

Are you getting any message on the screen telling you why it's not shutting off? I've seen things like "Engine on due to low temperature" "engine on due to warming up" "Engine on due to steering wheel movement" "Engine on due to seat belt disconnected" etc. You should be able to review the Auto Start Stop messages from the MPG/Fuel economy screen.

 

The system automatically enables every time you start your vehicle if:

- You do not press the Auto StartStop button (not illuminated).
- Your vehicle exceeds an initial speed of 3 mph (4 km/h) after you have initially started your vehicle.
- You have stopped your vehicle.
- Your foot is on the brake pedal.
- The transmission is in drive (D).
- The driver door is closed.
- There is adequate brake vacuum.
- The interior compartment has cooled or warmed to an acceptable level.
- The front windshield defroster is off.
- You have not turned the steering wheel rapidly or you do not have it at a sharp angle.
- The vehicle is not on a steep road grade.
- The battery is within optimal operating conditions (battery state of charge and temperature in range).
- The engine coolant is at operating temperature.
- Elevation is below about 10000 feet (3048 meters).
- Ambient temperature is moderate.
- You have selected 4X2 or Auto mode.
- The trailer is not connected.
- You have not selected Tow haul.
- You have not selected Manual or Sport mode.

Note: The system allows multiple successive Auto StartStop events, but it may not operate in conditions of heavy traffic or in extended low speed operation.

Note: The green Auto StartStop indicator light on the instrument cluster will illuminate to indicate when the automatic engine stop occurs.

Note: If the instrument cluster is equipped with a grey Auto StartStop indicator light, it is illuminated when automatic engine stop is not available due to one of the above noted conditions not being met.


Any of the following conditions will result in an automatic restart of the engine:

- You have removed your foot from the brake pedal.
- You press the accelerator pedal.
- You press the accelerator and the brake pedal at the same time.
- The driver safety belt becomes unfastened or the driver door is ajar.
- You have moved the transmission from drive (D) to any gear except park (P).
- Your vehicle is moving.
- The interior compartment does not meet customer comfort when air conditioning or heat is on.
- Fogging of the windows could occur and the air conditioning is on.
- The battery is not within optimal operating conditions.
- You have exceeded the maximum engine off time.
- When you press the Auto StartStop button with the engine automatically stopped.
- The front defroster is turned to the Max setting.

Any of the following conditions may result in an automatic restart of the engine:

- You have increased the blower fan speed or changed the climate control temperature.
- You have an electrical accessory turned on or plugged in.

Note: You may notice that the climate seat fan fluctuates during an automatic restart.

 

No messages.

 

You will have a message of some sort even if the message is “Engine On Normal Operation”.

From your mpg screen it’s a couple of clicks down if memory serves. When at a stop read what it says. It will tell you why the system is disabled if the system is disabled.

 

I'll look. Thanks.

 

I also was having the same issue where it seemed the s/s was not working when it used to or not as much as it had, then it hasn't engaged s/s for almost 2 months. Checked the battery and it was only at 20% charge, alternator was checked and good. So the dealership is looking at it on Friday and suspect it is possibly just a bad battery. Said that they have had issues with these batteries.
2018 XLT screw so the battery is only a year old.

 

Mine seems to start fine.
Did you have any other issues/indications besides the *** not doing it's thing?

 

+1 it tells you on the screen its status. When you think it should come on, take a look. I think you can also leave it on that screen for continuous readouts.