Auto Start/Stop FORScan Issue on 2019

[David1986]

I don’t mind it some days then at times it can be annoying. If it functioned a little more smoother mists folks would be fine with it. Sometimes it shakes the truck restarting. Also can be a pain sitting in traffic and try to turn the steering wheel to quickly change lanes.

I will get used to it after awhile.

 

[realjones88]

You're not disabling the battery management system at all. You're changing the logic circuit of the Auto Stop/Start ONLY.

Disagree with you this one. Forscan disables BMS (entirely) which in turn disables start/stop. I am understanding you right you think BMS keeps operating as usual after the Forscan change?

There are definitely threads on the F150 forum of people not wanting to use Forscan because they want to keep BMS active for whatever reason. The spreadsheet literally says it turns off start/stop by disabling BMS.

For example here is a thread discussing charging changes with regards to start/stop. Seems pretty clear Forscan is disabling BMS entirely
https://www.f150forum.com/f118/2018-2019-f150-auto-start-stop-mess-fix-425608/index15/#post5914838

 

[4rdFan]

Disabling BMS impacts two things (1) the load shed strategy during high load scenarios (for example, you might notice heated seats/heated steering wheel turns off temporarily) and (2) the alternator will never be in free spin mode, meaning the battery will be constantly charging.

 

[blwn]

I know it has been mentioned before, but still feel like it's worth repeating...

If you back your foot off the brake after coming to a stop, you can easily avoid Auto Start/Stop from engaging. I can keep the truck running when I want to, but when I know I'm going to be stopped for a while or want it to shutoff I just push the brake down further.

Maybe it's just a habit from trying not to hold the brakes more than needed especially when they're hot, but I've never felt the need to disable or turn off Auto Start/Stop. Try easing off the brake a little when you come to a stop and see if this works for you

 

[FL4x4]

Disagree with you this one. Forscan disables BMS (entirely) which in turn disables start/stop. I am understanding you right you think BMS keeps operating as usual after the Forscan change?

There are definitely threads on the F150 forum of people not wanting to use Forscan because they want to keep BMS active for whatever reason. The spreadsheet literally says it turns off start/stop by disabling BMS.

For example here is a thread discussing charging changes with regards to start/stop. Seems pretty clear Forscan is disabling BMS entirely
https://www.f150forum.com/f118/2018-2019-f150-auto-start-stop-mess-fix-425608/index15/#post5914838

I stand corrected. I have no issues disabling the BMS and have had ZERO issues with the charging system.

Here's what the Ford Manual says about the BMS:

Battery Management System (If Equipped)
The battery management system monitors battery conditions and takes actions to extend battery life. If excessive battery drain is detected, the system temporarily disables some electrical systems to protect the battery.

Systems [temporarily disabled] included are:
• Heated rear window.
• Heated seats.
• Climate control.
• Heated steering wheel.
• Audio unit.
• Navigation system.

A message may appear in the information displays to alert you that battery protection actions are active. These messages are only for notification that an action is taking place, and not intended to indicate an electrical problem or that the battery requires replacement.

After battery replacement, or in some cases after charging the battery with an external charger, the battery management system requires eight hours of vehicle sleep time to relearn the battery state of charge. During this time your vehicle must remain fully locked with the ignition switched off.

Note: Prior to relearning the battery state of charge, the battery management system may temporarily disable some electrical systems.

Page 367
F-150

 

[FL4x4]

The Ford Manual also says this about connecting Accessories ...

Electrical Accessory Installation

To make sure the battery management system works correctly, do not connect an electrical device ground connection directly to the battery negative post. This can cause inaccurate measurements of the battery condition and potential incorrect system operation.

Note: If you add electrical accessories or components to the vehicle, it may adversely affect battery performance and durability. This may also affect the performance of other electrical systems in the vehicle.

 

[Fireguy144]

Ohh, so the gray icon will remain on the gauge cluster screen even though it’s disabled? And the button essentially does nothing now? I didn’t try driving with it, I just noticed the gray icon was still there after recoding so I figured it didn’t work.

hi
I seen a YouTube video on this. the guy said it needs to be disabled in three locations.the switch, the dash and in the actual computef

 

[MAMiller44]

I stand corrected. I have no issues disabling the BMS and have had ZERO issues with the charging system.

Here's what the Ford Manual says about the BMS:

Battery Management System (If Equipped)
The battery management system monitors battery conditions and takes actions to extend battery life. If excessive battery drain is detected, the system temporarily disables some electrical systems to protect the battery.

Systems [temporarily disabled] included are:
• Heated rear window.
• Heated seats.
• Climate control.
• Heated steering wheel.
• Audio unit.
• Navigation system.

A message may appear in the information displays to alert you that battery protection actions are active. These messages are only for notification that an action is taking place, and not intended to indicate an electrical problem or that the battery requires replacement.

After battery replacement, or in some cases after charging the battery with an external charger, the battery management system requires eight hours of vehicle sleep time to relearn the battery state of charge. During this time your vehicle must remain fully locked with the ignition switched off.

Note: Prior to relearning the battery state of charge, the battery management system may temporarily disable some electrical systems.

Page 367
F-150

So long story short...if you disable BMS to get rid of auto start. Don’t be a ******* and run your battery down lol. I always monitor my battery when I am running accessories for any reason without the engine running so I’m not worried there.

I do have a Cobb Accessport on the way anyways so I’m going to see how I like Cobb’s take on disabling auto start.

 

[FL4x4]

Disabling BMS impacts two things (1) the load shed strategy during high load scenarios (for example, you might notice heated seats/heated steering wheel turns off temporarily) and (2) the alternator will never be in free spin mode, meaning the battery will be constantly charging.

I disagree with the item #2 where you state the alternator will never be in a free spin mode.

As an electronics technician, I can assure you that the alternator's job is to ALWAYS charge the battery and supply all of the electrical power needs of the vehicle.
To make sure I wasn't passing on bad info, I checked with a buddy of mine who was a Ford master tech and he confirmed what I learned in electronics school.

In modern Alternators the rotor's magnetic field is produced by a field coil electromagnet. Alternators use a rotor winding which allows control of the alternator's generated voltage by varying the current in the rotor field winding.

A voltage regulator (which is NOT the BMS) controls the field current of the electromagnet to keep output voltage constant. If the output voltage from the stationary armature coils drops due to an increase in demand or slower RPM, more current is fed into the rotating field coils through the Voltage Regulator. This increases the magnetic field around the field coils which induces a greater voltage in the armature coils. The output voltage is then brought back up to its original value.

This is why an alternator can and will produce the same output voltage at any RPM. Slower RPM, the voltage regulator increases the current to the electromagnet, maintaining the set voltage. Higher RPM, the voltage regulator reduces the current to the electromagnet to maintain the set voltage.

According to my buddy, Ford introduced the BMS when vehicles started using the Auto Start/Stop (A.S.S.) systems. The BMS's job is to reduce the load on the electrical system (if needed) when the truck turns off when the A.S.S. engages at a stop, in order to protect the battery from discharging too much and ensure the truck has enough battery power to restart when you release the brake.

 

[Johndeere99]

I have a Forscan question I hope someone can help me with. Will Forscan work on a 2019 Navigator? I have a 14 and a 18 Raptor and a 19 Navigator. Im not familiar with Forscan so Im wondering if there are different programs for the different vehicles? I had tolerated the auto stop-start on the 18 until recently just unplugging the trailer plug under the dash and all is fine. But this 19 Navigator has pushed me over the edge. It has the piano key shift and is more aggravating. When I pull into the garage to park I stop, the motor shuts off, hit the PARK piano key, the motor restarts, then hit the stop button to kill the engine. Really wares me out. I know you can just hit the stop ignition button and it will go to park but just doesn't seem right not physically putting it in PARK. May have to invest in Forscan for the Navigator.
Thanks for any help you can provide.