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Parking Brake Phenomenon

tsmithlxix

Member
Sep 7, 2018
65
45
DE
Short story: It appears that if both parking brakes decide to stop working while you're driving, when you get to your destination the car will only shift into Neutral and will not shift into Park. Hopefully, I get to verify this theory later today.

FYI: 2015 Model S85D, ~120K miles

Longer version: Last Sat (12Dec) I got the parking brake 'fault' message. When I returned home I shifted the car in-and-out of Park/Reverse/Drive a few times and noticed that I could hear the parking brake activate on the passenger side only. I pulled the parking brake calipers off of both sides (to inspect/compare them) and noticed that the plastic motor cover was missing from the driver's side. It appeared that water had flooded the electric motor so that is possibly why it was not working. (Dammit, I didn't think to hook the right caliper up to the left connection to make sure the connection was working. Dammit. I'll find out tonight.) Anyway... so I ordered a driver's side assembly (which should be delivered today, 21Dec).
I was able to drive fine with the fault for the rest of the weekend, then to work Mon-Wed (145 mile commute, round-trip) of last week. Then on Thurs (17Dec) when I got to work the car would not shift into Park at all. I tried holding the Park button... nothing. I tried a hard reset, I tried opening the door while the car was in gear (Drive and Reverse)... nothing. The car would just shift into Neutral instead of Park. Since the car would now just ROLL, I parked against the curb and started making phone calls. The Tesla service center was SURE that I was mistaken, so I left work early to stop by the shop. They were able to see me right away since this is considered a SAFETY issue. Nice! When I got to the shop, they tried all of the same things that I tried yet the car would still only shift to Neutral.
Besides being able to roll away in Neutral, a couple of other issues I found is that the car could not be 'powered down' while in Neutral so your daytime running lights remain on. But the biggest issue (yes, bigger than not being able to shift to Park) is that since the car is not in Park, you can't open the charge door to charge the car. And even if you could open the charge door, the car still will not charge if the car is not in Park. The service guys said that they didn't even have a jerry-rigging way to work around that issue and they've never seen this happen to a car before. So I drive home with about 26 miles left in reserve.
I've come to the conclusion that the car waits for a signal from a pressure(?) or reed(?) switch in the brake assembly before the car actually shifts to Park. (I've never noticed if I heard the brakes actuate before or after the car shifts to Park. I'll have to look for that when it's fixed. Some of you can check now.) Since the parking brake signals between both sides are parallel, all will work fine as long as one brake is working. That's why I was able to continue driving over 4 days with a non-working driver's side parking brake. I'm 'assuming' that my passenger side brake failed on the drive to work. When I parked at work, since the car saw neither brake actuate, it wouldn't shift into park. "Maybe" that's a safety feature so that an owner doesn't get a false sense of security with the car being in "PARK" yet able to roll? I have no idea.
Anyway, I just noticed on my Blink cam that the FedEx guy just dropped off one of my brakes and the other should be in later today also. Once two working assemblies are installed, I'll find out if my theory is correct or if I'll need to 'creep' to the service center. (FYI, the car has been sitting since Thurs and the mileage has only dropped from about 15 to 11 miles in the 'tank' in 4 days. That's actually pretty good; especially, for cold weather (unheated garage). BUT, I also have a trickle charger (2 amp) hooked up to the 12V battery so that the high-voltage battery doesn't have to worry about keeping it charged.)

Fun stuff. :)
 

Ostrichsak

Active Member
Sep 6, 2018
3,331
3,288
Colorado, USA
What happens if you try to force the car into park by using the anti-roll safety feature? Sit in the car with the seat belt off and let it actually roll w/o touching the brake or gas pedals which would normally cause the car to throw itself into park because it thinks you forgot to and the car is rolling freely. Maybe this will trigger an emergency situation that the computer will see as a reason to override whatever lack of signals it's getting for accessing the park mode traditionally? It wouldn't solve your overall problem but might at least let you open the charge port and get a charge on it.
 
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Reactions: tsmithlxix
Sep 23, 2020
480
411
Sacramento CA
What happens if you try to force the car into park by using the anti-roll safety feature? Sit in the car with the seat belt off and let it actually roll w/o touching the brake or gas pedals which would normally cause the car to throw itself into park because it thinks you forgot to and the car is rolling freely. Maybe this will trigger an emergency situation that the computer will see as a reason to override whatever lack of signals it's getting for accessing the park mode traditionally? It wouldn't solve your overall problem but might at least let you open the charge port and get a charge on it.

So I'm not the most superstitious guy - but you named your first Tesla after the ill-fated Apollo 1 disaster ?
 
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Reactions: tsmithlxix

tsmithlxix

Member
Sep 7, 2018
65
45
DE
What happens if you try to force the car into park by using the anti-roll safety feature? Sit in the car with the seat belt off and let it actually roll w/o touching the brake or gas pedals which would normally cause the car to throw itself into park because it thinks you forgot to and the car is rolling freely. Maybe this will trigger an emergency situation that the computer will see as a reason to override whatever lack of signals it's getting for accessing the park mode traditionally? It wouldn't solve your overall problem but might at least let you open the charge port and get a charge on it.

I tried that last Thurs. I also tried to let it roll then open the door... nothing. :)
 

Ostrichsak

Active Member
Sep 6, 2018
3,331
3,288
Colorado, USA
So I'm not the most superstitious guy - but you named your first Tesla after the ill-fated Apollo 1 disaster ?

It seemed fitting given the train wreck of a delivery process, subsequent lost title work for half a year, the empty promises of the vehicle's condition and the blatant outright lies about how we'd be taken care of all coupled with the endless nightmares that ensued over all of that while trying to seek resolution and the complete lack of desire on Tesla's part to help us out with any part of it. Somehow a space program disaster feels "light" by comparison.

The good news is that we're on Apollo 5 now and all is well. lol
 

Ostrichsak

Active Member
Sep 6, 2018
3,331
3,288
Colorado, USA
I tried that last Thurs. I also tried to let it roll then open the door... nothing. :)
Dang, I tried.

I wasn't sure if you mentioned that in your post as I read massive parts of it but was also distracted and thought maybe you hadn't mentioned it or I may have missed it.

Welp, I'm all out of ideas!

goodluckwiththat.jpg
 
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Reactions: tsmithlxix

maximizese

Member
Jan 16, 2018
466
446
California
Thanks for sharing your information and I hope you're able to fix it. I'm not sure when the car shifts the drivetrain into park, but I assume it's simultaneous with the parking brake actuator. Our 2013 Fiat 500e makes a mechanical sound when the car goes into park and starts to roll when either on an incline or a given a little shove. I'm told it's large pin that locks at least one of the gears. As for the Tesla, my guess is that the software written for the car did not factor in such a failure and/or figured if such a thing were to happen that the owner would immediately bring into the Service Center for repair. I broke one of my guidelines when I bought our Model S; I vowed to never buy a car that lacks a mechanical parking brake...but I compromised my values.

Please keep us updated on your findings.
 
Sep 23, 2020
480
411
Sacramento CA
It seemed fitting given the train wreck of a delivery process, subsequent lost title work for half a year, the empty promises of the vehicle's condition and the blatant outright lies about how we'd be taken care of all coupled with the endless nightmares that ensued over all of that while trying to seek resolution and the complete lack of desire on Tesla's part to help us out with any part of it. Somehow a space program disaster feels "light" by comparison.

The good news is that we're on Apollo 5 now and all is well. lol
OK - very good reason for the Apollo 1 designation...
 
Sep 23, 2020
480
411
Sacramento CA
If this might be software related - what about having Tesla send an OTA update ? Go backwards to a previous firmware version etc ? Maybe that will jar the car into submission.

If you're still charging the 12V this shouldn't kill your remaining range... which is more precious than the Covid vaccine at this point.
 

tsmithlxix

Member
Sep 7, 2018
65
45
DE
Thanks for sharing your information and I hope you're able to fix it. I'm not sure when the car shifts the drivetrain into park, but I assume it's simultaneous with the parking brake actuator. Our 2013 Fiat 500e makes a mechanical sound when the car goes into park and starts to roll when either on an incline or a given a little shove. I'm told it's large pin that locks at least one of the gears. As for the Tesla, my guess is that the software written for the car did not factor in such a failure and/or figured if such a thing were to happen that the owner would immediately bring into the Service Center for repair. I broke one of my guidelines when I bought our Model S; I vowed to never buy a car that lacks a mechanical parking brake...but I compromised my values.

Please keep us updated on your findings.

Like I noted, my guess is that it actually IS in the software and is possibly written that way for safety reason. If bot parking breaks malfunction I assume it's better to (besides the fault messages) alert the driver that his car will roll by only allowing it to shift to Neutral. That's a bigger alert than just a fault message because it forces you to notice that something is VERY wrong. If it allows you to shift to Park, you may not notice and your car may not start to roll right away if it a somewhat level surface... until someone comes to your desk and say that 'your car just drove across the parking lot by itself and hit mine." LOL!:D:D:D:D
 

tsmithlxix

Member
Sep 7, 2018
65
45
DE
Short story: It appears that if both parking brakes decide to stop working while you're driving, when you get to your destination the car will only shift into Neutral and will not shift into Park. Hopefully, I get to verify this theory later today.

FYI: 2015 Model S85D, ~120K miles

Longer version: Last Sat (12Dec) I got the parking brake 'fault' message. When I returned home I shifted the car in-and-out of Park/Reverse/Drive a few times and noticed that I could hear the parking brake activate on the passenger side only. I pulled the parking brake calipers off of both sides (to inspect/compare them) and noticed that the plastic motor cover was missing from the driver's side. It appeared that water had flooded the electric motor so that is possibly why it was not working. (Dammit, I didn't think to hook the right caliper up to the left connection to make sure the connection was working. Dammit. I'll find out tonight.) Anyway... so I ordered a driver's side assembly (which should be delivered today, 21Dec).
I was able to drive fine with the fault for the rest of the weekend, then to work Mon-Wed (145 mile commute, round-trip) of last week. Then on Thurs (17Dec) when I got to work the car would not shift into Park at all. I tried holding the Park button... nothing. I tried a hard reset, I tried opening the door while the car was in gear (Drive and Reverse)... nothing. The car would just shift into Neutral instead of Park. Since the car would now just ROLL, I parked against the curb and started making phone calls. The Tesla service center was SURE that I was mistaken, so I left work early to stop by the shop. They were able to see me right away since this is considered a SAFETY issue. Nice! When I got to the shop, they tried all of the same things that I tried yet the car would still only shift to Neutral.
Besides being able to roll away in Neutral, a couple of other issues I found is that the car could not be 'powered down' while in Neutral so your daytime running lights remain on. But the biggest issue (yes, bigger than not being able to shift to Park) is that since the car is not in Park, you can't open the charge door to charge the car. And even if you could open the charge door, the car still will not charge if the car is not in Park. The service guys said that they didn't even have a jerry-rigging way to work around that issue and they've never seen this happen to a car before. So I drive home with about 26 miles left in reserve.
I've come to the conclusion that the car waits for a signal from a pressure(?) or reed(?) switch in the brake assembly before the car actually shifts to Park. (I've never noticed if I heard the brakes actuate before or after the car shifts to Park. I'll have to look for that when it's fixed. Some of you can check now.) Since the parking brake signals between both sides are parallel, all will work fine as long as one brake is working. That's why I was able to continue driving over 4 days with a non-working driver's side parking brake. I'm 'assuming' that my passenger side brake failed on the drive to work. When I parked at work, since the car saw neither brake actuate, it wouldn't shift into park. "Maybe" that's a safety feature so that an owner doesn't get a false sense of security with the car being in "PARK" yet able to roll? I have no idea.
Anyway, I just noticed on my Blink cam that the FedEx guy just dropped off one of my brakes and the other should be in later today also. Once two working assemblies are installed, I'll find out if my theory is correct or if I'll need to 'creep' to the service center. (FYI, the car has been sitting since Thurs and the mileage has only dropped from about 15 to 11 miles in the 'tank' in 4 days. That's actually pretty good; especially, for cold weather (unheated garage). BUT, I also have a trickle charger (2 amp) hooked up to the 12V battery so that the high-voltage battery doesn't have to worry about keeping it charged.)

Fun stuff. :)

**** UPDATE ****
(I didn't know if the update should be posted here in the thread or if I should have edited the original message... but since I don't know how to edit the original, here it is.)
Okay, all is well now. Both parking brakes were delivered today and I've installed both. As soon as I installed and plugged in the first brake (which happened to be the driver's side) the car locked the brake and shifted to Park. Yayyyy, I now have PARK again. Anyway, as far as testing goes... Yes, with one brake plugged in and the other unplugged, the car will still shift to park and actuate the single parking brake (This is what allowed me to drive for 4+ days after I noticed that the first brake wasn't working.) With both brakes unplugged the car does remain in Neutral and will not go into Park (I believe for the safety reason I mentioned above.) And of course with both brakes plugged in and operable, all is well with the world.
 

Ostrichsak

Active Member
Sep 6, 2018
3,331
3,288
Colorado, USA
**** UPDATE ****
(I didn't know if the update should be posted here in the thread or if I should have edited the original message... but since I don't know how to edit the original, here it is.)
Okay, all is well now. Both parking brakes were delivered today and I've installed both. As soon as I installed and plugged in the first brake (which happened to be the driver's side) the car locked the brake and shifted to Park. Yayyyy, I now have PARK again. Anyway, as far as testing goes... Yes, with one brake plugged in and the other unplugged, the car will still shift to park and actuate the single parking brake (This is what allowed me to drive for 4+ days after I noticed that the first brake wasn't working.) With both brakes unplugged the car does remain in Neutral and will not go into Park (I believe for the safety reason I mentioned above.) And of course with both brakes plugged in and operable, all is well with the world.
Nice! Glad you got that sorted and in relatively quick fashion too. Probably seemed like an eternity to you though. You didn't mention warranty and you ordered the parts and did the works yourself so I assume you were out of the warranty period, right?

Also, this forum time gates the "edit" option of posts for some odd reason. You can edit your own post for a short period after posting and then it lives forever as posted... grammar errors, typos and all.
 

tsmithlxix

Member
Sep 7, 2018
65
45
DE
Nice! Glad you got that sorted and in relatively quick fashion too. Probably seemed like an eternity to you though. You didn't mention warranty and you ordered the parts and did the works yourself so I assume you were out of the warranty period, right?

Also, this forum time gates the "edit" option of posts for some odd reason. You can edit your own post for a short period after posting and then it lives forever as posted... grammar errors, typos and all.

Nah, the wait wasn't too bad. the car became undrivable on Thurs and was fixed Mon eve. Not too shabby. And this thing was out of warranty less than 15 months after I got it. :)

I noticed the editing rule after I posted the update. I noticed the 'Edit' selection after I posted it then noticed it missing later. I figured that the editing actually does time out at some point.
 

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