Possible Bug with Reverse Brake Assist

[Jimrpa]

I think I’ve found a bug in Reverse Brake Assist. If someone else could try to duplicate this behavior, I’d appreciate it.

Here is the scenario:
In the morning, I back out of my driveway into my small street, then drive off. Everything is happy, no alerts, warnings, etc.

A buddy is now staying at my house for a while. Now, here’s the scenario:
In the morning, I back out of the garage, stop (the car is still in reverse), unlock the doors, my buddy gets in the front passenger seat and closes the door. After he closes the door, the error message “Reverse brake assist not available” appears on the instrument panel for about 5 seconds, then goes away I continue to back out of my driveway into the street and proceed on my way.

This scenario is repeatable. Happens every time. Start car, back out of driveway, stop, unlock doors, open passenger door, passenger enters, closes passenger door, error message appears.

Can anyone else duplicate that?

Premium ER AWD Feb build date Power Up 1.4. Pretty recent software installed by dealer.

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[AzCoronaDog]

Interesting find.
Ford should be paying us to QA this beta version of the MME software!

 

[IMDIDOC]

I think I’ve found a bug in Reverse Brake Assist. If someone else could try to duplicate this behavior, I’d appreciate it.

Here is the scenario:
In the morning, I back out of my driveway into my small street, then drive off. Everything is happy, no alerts, warnings, etc.

A buddy is now staying at my house for a while. Now, here’s the scenario:
In the morning, I back out of the garage, stop (the car is still in reverse), unlock the doors, my buddy gets in the front passenger seat and closes the door. After he closes the door, the error message “Reverse brake assist not available” appears on the instrument panel for about 5 seconds, then goes away I continue to back out of my driveway into the street and proceed on my way.

This scenario is repeatable. Happens every time. Start car, back out of driveway, stop, unlock doors, open passenger door, passenger enters, closes passenger door, error message appears.

Can anyone else duplicate that?

Premium ER AWD Feb build date Power Up 1.4. Pretty recent software installed by dealer.

During my dealer software update, it reported the same. He looked it up and thought it may be due to being in the garage with the car door open, but you report it's out. Possible since it's still in reverse it thinks it still in the garage?

 

[Jimrpa]

During my dealer software update, it reported the same. He looked it up and thought it may be due to being in the garage with the car door open, but you report it's out. Possible since it's still in reverse it thinks it still in the garage?

The car door is not opened until the car is out of the garage, in the driveway.

 

[murphy62]

I had my dealer send the following to Ford.

Steven,



I have what I believe is a design flaw with my 2021 Ford Mustang Mach-E Premium.

VIN

My driveway is about 75 feet long and rises up from the street to the garage. When I back down the driveway as I near the street alarms go off and the car slams on the brakes. The reverse brake assist is seeing the street as an obstacle that it is going to collide with. The first time this happened full accelerator pedal moved the car backwards at a creep velocity until the car leveled out.

I had the same problem with my Tesla but it has an air suspension and raising the car to very high avoided the problem. The car geo-fenced that change and always raises the suspension in my driveway.

My only option with the Mach-E is to turn Reverse Brake Assist off. The downside of that is that every time I shift into reverse I get a big warning on the driver screen that says "Reverse Brake Assist OFF". I know it is turned off and don't need to be reminded since I can never turn it back on. In spite of it being turned off I still get beeps as I get near the street but at least the brakes don't get applied.

Please submit this to Mach-E Engineering so they can come up with a solution.

One solution would be to geo-fence my driveway and block the warnings and braking when inside of the fence.

Another, assuming the car knows when it is not level, would be to block the warnings when backing down hill.

And no I am not going to dig into the menus and turn it back on every time I get on the street.


Thanks,

John

 

[bballpirate]

Happens to me every time I back out of the garage and then the family hops in. Since it went away after they closed the door I did not think anything of it.

 

[macchiaz-o]

@Jimrpa,

From your mouth to Ford's ears?

Check out TSB 21-2249 for this concern, shared by Sam @breeves002:

https://www.macheforum.com/site/thr...tance-feature-concerns-and-or-ipma-dtcs.8177/

 

[Jimrpa]

@Jimrpa,

From your mouth to Ford's ears?

Check out TSB 21-2249 for this concern, shared by Sam @breeves002:

https://www.macheforum.com/site/thr...tance-feature-concerns-and-or-ipma-dtcs.8177/

Cool! Thanks and thanks to Sam @breeves002 as well! Here’s an update based on more testing:
If I put the car into Park BEFORE my passenger opens the door, I don’t get the alert. I’ve repeated this several times and confirmed the behavior both ways, so the cause seems to be car in reverse, open passenger door?

 

[mpshizzle]

Maybe this is related maybe not, but I had an odd experience like this when I took my car out to the salt flats.

After a few minutes of being out there I got several warnings that none of the sensor based systems were available. Pre collision, adaptive cruise, rear brake assist, blis, etc. All of it gone.

I just assumed it was because I was in a big, flat place and none of the sensors could see anything but big, wide open space. Like maybe that made it freak out and think it was blind

 

[TruWrecks]

If you are talking about Auto-Hold it disables every time a door opens. It is in the manual. I can make that message appear 20 times in a row in my carport without moving the car an inch. Put the car in reverse in OPD with Auto-Hold and open and close the door. Repeat infinitely if you wish.

 

[Gimme_my_MME]

Gotta be ghosts

 

[krafty81]

My personal theory is that it has to do with shadowing. I noticed one time the car got a little spastic with cruise control, lane centering on when a sharp shadow went away on the left side, it kind of wanted to follow it. I think somehow the reverse brake assist may see a shadow as an object and puts on the brakes. When the sun is right overhead my garage I sometimes get the brake being applied when in reverse and the associated warning.

 

[breeves002]

Yup I have the same issue with reverse brake assist not available. What I’ve started doing is putting it in park before people get in so it doesn’t do it.

 

[65coupe&21mache]

Just happened to me yesterday. I picked the wife up from a store and as she was getting it I shifted into reverse to get a little more space to pull out and the error briefly appeared, it might have been when her door was still open.

 

[mpshizzle]

I just had a thought about this. I wonder if it's purposeful. There are sensors all around the car that are enabled when you are in reverse. So I'm wondering if having a door open partially blocks the view of one of the front end sensors so they just turn it off

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