Uncommanded Parking Brake Activation

[x47]

This is not what I wanted to write for my first post, but here we go.

I've got a several month old 2023 F150 Lightning Lariat ER with about 3000 miles ... and the parking brake keeps coming on when the vehicle comes to a stop. It isn't auto hold, the doors are closed, etc. You have to fiddle with the door, shifter, and parking brake button quite a few times before the issue goes away. Not the best experience in a busy intersection.

Unfortunately for me the truck behaved when I took it into the dealership the first time for this issue. Usually it happens a few times a day. It isn't obvious how the condition can be cleared once it happens.

Pictures are worth a thousand words so a video should be better. Does anyone have any ideas what I can ask the dealership to look into when I go back?

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[The Weatherman]

Does this seem to occur when you are stoping on unlevel ground?

There is feature that sets the brake in this situation. It should release automatically thou when you begin to depress the accelerator.

 

[x47]

No! It happens when I'm in drive or reverse and pretty much anywhere around town. This video in particular was taken in a flat parking lot, and the parking brake turned on many times even when I remained in gear.

 

[The Weatherman]

If it’s not releasing at the lightest of touch on the accelerator then you need to take in to for service and work with them until you can get it to show out.

 

[x47]

To clarify this isn't an issue with auto-hold. That works as expected.

 

[Grumpy2]

There was a recent case of rear motor damage related to the parking brake, you should see dealer immediately, it may be mechanical and not just faulty electrical. That truck was out of service for awhile to get parts replaced.

https://www.f150lightningforum.com/...ing-with-red-fluid-leaking.19442/#post-390239

 

[x47]

Well there's no immediate evidence of the red liquid of motor death but I'll ask!

 

[TaxmanHog]

Is your seatbelt buckled?

 

[Heliian]

If it's not just your seatbelt then bring it to the dealer. The parking brake icon is just an icon on my truck. When the word brake comes up in red it usually means a brake fault.

 

[hturnerfamily]

it looks like the system is not 'seeing' the vehicle as 'in gear', and protecting the possibility of rollback by applying the parking brakes - seems like a small SENSOR that is the issue.

 

[x47]

Is your seatbelt buckled?

Yep

If it's not just your seatbelt then bring it to the dealer. The parking brake icon is just an icon on my truck. When the word brake comes up in red it usually means a brake fault.

I'm trying to get in touch with them now.

it looks like the system is not 'seeing' the vehicle as 'in gear', and protecting the possibility of rollback by applying the parking brakes - seems like a small SENSOR that is the issue.

That's kind of what I'm wondering.

New information -- as of today the truck is now sometimes showing "Auto-Hold System Fault". Auto-hold was disabled by the computer this morning. When I tried enabling it again it complained it could not do so as a door was open. No doors were open and no door open indicators were on.

Looks like one computer is getting one story and another computer is getting another story.

 

[TaxmanHog]

When I tried enabling it again it complained it could not do so as a door was open. No doors were open and no door open indicators were on.

Looks like one computer is getting one story and another computer is getting another story.

We've had recent software updates for the "door modules" but this might be an actual failure of the module or wires to switches & sensors.

 

[Ford Motor Company]

This is not what I wanted to write for my first post, but here we go.

I've got a several month old 2023 F150 Lightning Lariat ER with about 3000 miles ... and the parking brake keeps coming on when the vehicle comes to a stop. It isn't auto hold, the doors are closed, etc. You have to fiddle with the door, shifter, and parking brake button quite a few times before the issue goes away. Not the best experience in a busy intersection.

Unfortunately for me the truck behaved when I took it into the dealership the first time for this issue. Usually it happens a few times a day. It isn't obvious how the condition can be cleared once it happens.

Pictures are worth a thousand words so a video should be better. Does anyone have any ideas what I can ask the dealership to look into when I go back?

Hi there! Will you send us a message with your VIN and your local Ford dealer? I can look into things on my end.

 

[TomB985]

As I read through your post, my first thought was that your truck thinks the door is open. I then saw your second post about not being able to re-enable auto hold because your door is open.

I’m pretty sure that’s where your problem is. A bad switch or wiring problem is telling your truck that you’ve opened the door, and it automatically sets the parking brake for safety. This feature has good intentions, but makes it really frustrating to park my trailer because I’m in and out of the truck several times.

Your truck is acting perfectly normal if you were opening your door when this happens.

 

[x47]

Now the question is which switch / wire is bad such that the instrument cluster doesn't think the door is open but another engine control module does.

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