Auto Stop/Start Not Working

[oreomuffin]

@oreomuffin Checking the Owner's Manual pages 168-170 provides information (like that above) on Auto Start/Stop and why it will not operate with some threads confirming what is said. Just passing along info.

I appreciate it, but for me this is just a symptom of my issue. I shouldn’t have to charge my battery one to two times per week to prevent deep sleep notifications. That’s my bigger issue. The dealer already had it once for a few days and couldn’t tell me why it was happening.

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[grumpyunk]

Oreo, similar situation. Fully charge(13V) overnight, and within a few days, battery V drops to ~12.3V.
AutoSS works until the battery voltage drops a bit more below that number, currently functioning.

The battery will not accept a charge from the charging system after a 500 mile drive,
OR, the charging system will not product V or A enough to charge the battery after a 500 mile run.
It may be the ECM is limiting the charging system output, or it may be the battery requires a higher voltage to charge fully. Either way, the charge was low after 1000 miles of freeway driving, such that the Ass did not function. Battery tested good for CCA capacity.
The need to use an external charger to maintain the voltage is indication to me of a problem.
I would not accept that in a new vehicle, and would suggest you contact your dealer for a comprehensive charging system and battery test. That's what I will do when a slot becomes available.
tom

 

[LeersMav]

@oreomuffin Did Ford (not dealer) get involved with the dealer yet? I remember an earlier response that Ford wanted you VIN in a PM.

 

[grumpyunk]

@oreomuffin Did Ford (not dealer) get involved with the dealer yet? I remember an earlier response that Ford wanted you VIN in a PM.

Sorry for the delay in answering. Hadn't checked back.
Yes they did get in contact. The dealer checked the battery and it checked as having more than advertised CCA, so, essentially, a good battery.
Service offered an appointment about a month off, but I was unable to drop the truck as wife was not there to take me home, so I cancelled.
Since then, I have fully charged the battery using a 'smart' charger, over night.
I also reset the 'battery power control module'. If/when you charge using an external battery charger, Ford indicates to NOT use the "-" terminal for the clamp, as the 'module' does not like it. There is a post on the drivers side, under hood, that connects directly for charging, I guess.
To reset, flash the HI beams 5 times, then press the brake pedal 3X. Key ON, and the battery warning light should flash after the procedure. If it does not signal the 1st time, try again.
I do not know if this will affect my truck, but you can read all about it if you wish, and example article:
https://www.automasterx.com/how-to-reset-ford-battery-management-system/
tom

Added: the article I read that suggested to me that resetting the BMS was appropriate:
https://moundalexis.com/v2/2020/08/06/ford-bms.html
Pretty good explanation of the system.
tom

 

[teh603]

The battery will not accept a charge from the charging system after a 500 mile drive,
OR, the charging system will not product V or A enough to charge the battery after a 500 mile run.
It may be the ECM is limiting the charging system output, or it may be the battery requires a higher voltage to charge fully. Either way, the charge was low after 1000 miles of freeway driving, such that the Ass did not function. Battery tested good for CCA capacity.

So, I might've missed this, but have you checked the alternator and regulator? Or just the alternator if it's self- regulated?

I've had enough problems with my mom's old '73 F-100 that the alternator and regulator are the first thing to check when it's not charging. Yes, I know they're literally brand new from the factory. Let me tell you this story about the time my dad tried seven brand new alternators from three different stores and only one of them would charge...

 

[grumpyunk]

So, I might've missed this, but have you checked the alternator and regulator? Or just the alternator if it's self- regulated?

I've had enough problems with my mom's old '73 F-100 that the alternator and regulator are the first thing to check when it's not charging. Yes, I know they're literally brand new from the factory. Let me tell you this story about the time my dad tried seven brand new alternators from three different stores and only one of them would charge...

No. I have not checked the alternator for output. It is not the normal system that will pump a charge back into the battery immediately after starting the vehicle. It is controlled by the ECM and the "battery power module"(my words) that looks at voltage, amperage, temperature, phase of the moon... and regulates the charge based upon all that.
The system in mine kept the battery charged enough to start the engine and run mormal accessories, but apparently would not 'fully charge' the battery to its capacity after two 500-mile stretches of driving. The battery met is CCA rating and more when tested, the system did/does not fully charge the battery so the Auto Start/Stop will function.
Ford called and asked for my input but I was unable to take it in for a test and have not re-scheduled. I figured resetting the module couldn't hurt, but from ignorance.
tom

 

[ppagan2012]

CONFIRMED...
Doing a BMS (Battery Monitor System) reset with FORSCAN fixed the problem. I did it and it worked.

 

[bgn]

CONFIRMED...
Doing a BMS (Battery Monitor System) reset with FORSCAN fixed the problem. I did it and it worked.

Thank you. I will try this as well and report back to see if it fixes my issues. I've been hooking up my compressor to the negative terminal a lot, so maybe this is self inflicted lol.

Edit: confirmed working. Did the manual method of turning on accessory mode, flashing brights 5 times, and then pumping the brakes 3 times. Battery icon flashes 3 times and that's it.

 

[MakinDoForNow]

I have seen 12.8v on mine and the 12v bus will be at 14.7v and slowly drop presumably as the 12v gets charged. Since this follows the recommended charge rate for a 12v deep cycle battery, I assume that is what's in my hybrid.

 

[MakinDoForNow]

Thank you. I will try this as well and report back to see if it fixes my issues. I've been hooking up my compressor to the negative terminal a lot, so maybe this is self inflicted lol.

Edit: confirmed working. Did the manual method of turning on accessory mode, flashing brights 5 times, and then pumping the brakes 3 times. Battery icon flashes 3 times and that's it.

In the manual it states to not hook anything to battery ground post as it can mess up the bms. I read in manual that it can take up to 8 hours in hybrid for bms to relearn the soc of the 12v battery

 

[MakinDoForNow]

Modern cars don’t charge like older ones. I had a CRV that was having problems charging. There was a TSB out for a reflash that fixed everything. Alternators are smart these days. A lot of them only charge on deceleration.

In my CR-V I kept charge in battery by leaving running lights and fan on at medium speed. This draw insured that voltage on bus remained over 14volts and kept battery charged.

 

[Nightman]

I've had my mav for about a week an noticed my auto stop/start randomly seemed to stop working. I performed the BMS reset described and everything.

I ended up finding the culprit. When I have the front windshield defrost enabled by itself, then the auto stop system doesn't engage. If I have the defrost with any other vent selected it works as expected. This seems odd to me and doesn't seem to describe that scenario in the manual like the other scenarios where it doesn't engage by design.

 

[grumpyunk]

I've had my mav for about a week an noticed my auto stop/start randomly seemed to stop working. I performed the BMS reset described and everything.

I ended up finding the culprit. When I have the front windshield defrost enabled by itself, then the auto stop system doesn't engage. If I have the defrost with any other vent selected it works as expected. This seems odd to me and doesn't seem to describe that scenario in the manual like the other scenarios where it doesn't engage by design.

Selecting the defrost(windshield) mode may cause the A/C compressor to engage, which I think will/can cause the ASS to leave the engine running at idle. Most times the compressor is used to dehumidify the air blowing across the inner surface of the windshield and prevent frost/condensation from blocking the view. I have not tried pure defrost nor the mixed combo of floor/defrost to see if there is any difference. I may not even have ever selected defrost of any kind since purchase, so really can't state from experience.
tom

 

[jsus]

I've had my mav for about a week an noticed my auto stop/start randomly seemed to stop working. I performed the BMS reset described and everything.

I ended up finding the culprit. When I have the front windshield defrost enabled by itself, then the auto stop system doesn't engage. If I have the defrost with any other vent selected it works as expected. This seems odd to me and doesn't seem to describe that scenario in the manual like the other scenarios where it doesn't engage by design.

Heat and AC require the ICE. Only the fans are electric. So, if there's enough hot/cold air in the system, it may briefly shut off the ICE at a stop, but when it needs more hot/cold air, the ICE will kick back on to provide that.

Defrost would otherwise not work; the windshield would simply fog over. When I had my Bronco Sport (with the 1.5L EB), it would still shut off the engine when stopped if I left climate in auto. The windshield would indeed quickly fog over. Manually selecting front defrost would override this, which is what you are seeing.

The reason for that is that the AC compressor (again, powered by the ICE), serves to dehumidify the cabin/glass. That's part of the defrost mode. If the ICE shuts off, so does the compressor, so there goes your dehumidifier.

 

[Nw_adventure]

Anyone live at elevation and have the Auto/Start stop work below 40 degrees instead of just saying - Not active due to charging ? Thx -

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