Uncommanded Parking Brake Activation

[x47]

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

Message sent!

Sponsored

 

[kstype]

I saw a multiple posts about different sensors. I thought perhaps the vehicle tilt sensor is detecting a incline where none exists - curious if the driver display shows a tilt angle when you’re level, you would have to add that to your instrument cluster screen to see it.

 

[Randall Stephens]

I wouldn’t t be driving this. I’d have this thing parked at the dealer racking up time on the lot in case they can’t figure it out and you have to go the lemon route.

 

[Pioneer74]

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.

There was a situation on my 2018 truck that the interior lights wouldn't shut off because it thought one of the doors was open. I narrowed it down to the rear passenger door by, when the problem occurred, slamming shut each door until the problem went away.

Next time you have this problem, try getting out of the truck and "firmly" shutting each door individually to see if the problem clears up.

 

[Danface]

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.

That's the "don't sue us for doing something stupid" "feature". It sucks (but their lawyers love it!).

 

[rtk11226]

This has been happening to me but no where near as frequently. In my experience this situation occurs when backing up on soft ground to connect my trailer. Driver door is closed, no seat belt, but lots of braking as I slowly approach the trailer hitch while watching the backup camera. At some random time during the process I can hear the brake engage and then I’ll have to go through several iterations of releasing & re-releasing the brake. I thought I might have been doing something wrong but now I’m pretty sure it’s the truck. Hope we can get a solution since I’m not entirely sure I can reproduce this issue at the dealership on demand.

 

[jimfigler]

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.

this only happens when you put the vehicle in park on a hill . it doesnt happen on a hill where there might be a stop sign or red light

 

[x47]

I managed to capture some more information last night and today. Auto Hold System Fault and non-1PD issues both observed.

This is definitely looking like a computer somewhere thinks a door is open.

https://youtu.be/VBc5as2YzlE
https://youtu.be/AMwNZMJwf9Y

Other things I can confirm so far is that the before behavior didn't change after opening/closing any door, weather/rain appear to have no impact, the 12V battery voltage is nominal, all truck CSPs have been done (including the battery sensor replacement), and it's in this mode 95%+ of the time now.

 

[x47]

This has been happening to me but no where near as frequently. In my experience this situation occurs when backing up on soft ground to connect my trailer. Driver door is closed, no seat belt, but lots of braking as I slowly approach the trailer hitch while watching the backup camera. At some random time during the process I can hear the brake engage and then I’ll have to go through several iterations of releasing & re-releasing the brake. I thought I might have been doing something wrong but now I’m pretty sure it’s the truck. Hope we can get a solution since I’m not entirely sure I can reproduce this issue at the dealership on demand.

@rtk11226 is what you are seeing match the videos I put up today?

 

[farmtruck]

Yep



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



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.

What you just described is a CANbus fault. I had a tractor act like this a few years ago. When the fault fully failed, it locked the transmission up at 8 mph. A couple of broken ribs, $80000, and a terminator later, the problem was fixed. The bad terminator was on the HVAC controller. The faults were random and had nothing to do with the air conditioner.

 

[x47]

What you just described is a CANbus fault. I had a tractor act like this a few years ago. When the fault fully failed, it locked the transmission up at 8 mph. A couple of broken ribs, $80000, and a terminator later, the problem was fixed. The bad terminator was on the HVAC controller. The faults were random and had nothing to do with the air conditioner.

Ouch

One thing I can say is that my truck's issue is more prevalent now than it was a month or two ago. "Oh that was weird let's restart" has turned into "it happens almost every time I drive".

 

[rtk11226]

@rtk11226 is what you are seeing match the videos I put up today?

It is, but not as many iterations. As I mentioned, this has only ever happened when backing up to hook up my trailer… thankfully never at a busy intersection. I’ll try to see if I can trigger the problem on the street and report back if I have any success.

 

[Awj]

Yeah that's the message that shows up when you turn the vehicle on and put it into gear while the driver's door is still open... maybe a bad sensor or something.

 

[x47]

Something indeed. Tech got a good look at the issue today and, for now, Ford is paying for an F250 loaner.

 

[rtk11226]

I did some testing yesterday and was only ever able to get it to happen when the door was slightly ajar. It just might be my fault... not closing the door fully or opening the door too soon to check the hitch. I did run into a situation today that makes me think we need a bypass on the action of slamming the parking brake on when opening the door. I was off road in tall brush/weeds. I got out to open the tailgate and load some items. I tried to clear the driver door of brush/weeds but couldn't completely close the door. You can't move without completely closing the door. Since I didn't have the appropriate tools with me it took me a good while to remedy the issue. It would really be nice to be able to disable the parking pawl activation in certain situations where it is difficult, impractical or impossible to shut a door.

Sponsored