Conflicting parking brake failure messages

[David29]

In the past few days, my 2015 Model S has displayed two messages I had never seen before. The first time, it said the parking brake did not engage when I parked it, and warned that the car might roll away. This struck me as curious because I would think that the PARK feature would hold it in place, and indeed it showed no movement when I parked it in my sloping parking space.

The next time I used it, there was no message.

The third day, however, driving off resulted in a message that said the parking brake did not release and that brake damage could result if I kept driving. I pulled over, rolled down the windows, put the car into neutral, and let the car roll. I felt no resistance and heard no noise at all, certainly not a dragging brake. After driving a couple of miles, I felt the parking brake calipers, and both were cool, so they could not have been on much, if at all. And when I parked again, the contrary message appeared again, saying the parking brake was not engaged and the car might roll.

I have an upcoming service appointment for something else, so I added this to the notes.

In the meantime, I am curious if anyone else has seen either of these messages and what the actual failure was.
(And before anyone asks, yes, I live in the snowbelt, and I do have Tesla do the brake clean/lube service each winter. This year, it was done in late February, and I have driven less than a thousand miles since then.)

 

[tommytuna]

Similar situation for me today - did you ever figure out what happened/caused the error message?

 

[David29]

Similar situation for me today - did you ever figure out what happened/caused the error message?

Yes, I did, and I thought I posted about that. I must have posted elsewhere, and I apologize.

Turns out that one or possibly both of my parking brake calipers had failed. The Tesla parking brake calipers of this vintage (2015) have a screw mechanism to apply the caliper against the disc, and that failed. Tesla service replaced the parking brake calipers on both wheels under my ESA for the $200 fee. (I do not know if both calipers actually failed but I am not complaining to have two new ones.)

Tesla told me that mobile service could not replace the calipers because it required lifting the car so I had to make a service center appointment.* With the Covid-19 shutdown, I was not using the car much anyway, so the extra wait (2 weeks or so) for a service appointment was only a minor inconvenience.

I was undecided whether or not to drive the car, or whether I should call for a flatbed. On a day before the appointment, I repeatedly set and unset the parking brake, hoping I might free up the caliper(s). When the day came for the appointment, the brakes did not seem to be dragging very much, so I decided to risk driving the car. I drove the car carefully to the service center, which is (fortunately for me) only about 3 or 4 miles away. I stopped twice to check that the brake discs were not heating up -- I did not want Tesla to tell me I had to buy new discs because they had been damaged. I had no problems with the short drive.

*Just because of coincidental timing, the service appointment also included replacement of my MC1 computer and screen for the memory failure repair. As I recall, the combined work took only one or two days. All well since then, both brakes and the computer.

 

[Lauz]

If something like this happens while on the road? You can often free up the stuck p-brake by hitting park on/off multiple times. Once it releases? The offending brake can be removed in less than 10 minutes.

Chock all wheels to prevent car from rolling. Put into tow-mode. Tow-mode will back off both parking-brakes completely. Remove the wheel, unplug the cable to the p-brake, loosen the two bolts and remove it. Cancel tow-mode and remove wheel chocks.

Autopilot won’t work, but you can keep driving and the remains p-brake should be sufficient unless you park in SF.

Slightly used p-brakes can be sourced from eBay for cheap.