Driving to work today I was slowing from maybe 20 MPH with regen braking when I heard and felt a few "thumps" within about a 1-2 second period. They weren't loud, but definitely audible. It hasn't occurred again and everything seems to be normal. Any ideas what this might have been? I'll definitely be keeping an eye on it but just trying to get ahead of potentially a more serious issue later on. This is a 2015 Model S 85D.
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Thumping sound/feeling during regen braking?
- Thread starter shred86
- Start date
SeminoleFSU
Voluntaryist
Did you have TACC or AP on? If so, it can make the brake thump as it depresses and releases (more so releases) the pedal back up very quickly and it hits the upper threshold where the brake pedal returns to the fully upright position. To test if this is your problem, gently place your foot on top of the brake pedal and you'll feel it doing this when the car brakes itself. I was hearing this same noise and was freaking out until people explained it could be this and I discovered it was.
boonedocks
MS LR Blk/Blk 19”
TeslaS100Dfan on Twitter
This behavior is so bad that I don't use EAP 2.0 with my family in the car. Everyone complains about erratic & spastic braking (mostly the sound the pedal makes when snapping up and down) It is not near as bad with TACC alone which leads me to believe that the APE isn't powerful enough to handle both or completely different code is used for braking between TACC & EAP.
Oddly enough I tweeted Elon, Tesla & AK about this just this morning.
TeslaS100Dfan on Twitter
This behavior is so bad that I don't use EAP 2.0 with my family in the car. Everyone complains about erratic & spastic braking (mostly the sound the pedal makes when snapping up and down) It is not near as bad with TACC alone which leads me to believe that the APE isn't powerful enough to handle both or completely different code is used for braking between TACC & EAP.
Oddly enough I tweeted Elon, Tesla & AK about this just this morning.
TeslaS100Dfan on Twitter
SeminoleFSU
Voluntaryist
Yea I wish the EAP braking behavior would allow for a little more closing distance (closer than what you set up to maybe 3/4 car length) that way it could be programmed to behave more in a more "analog" manner using regen for as long as possible... Hopefully they could tweak the brake behavior to feather the pedal more rather like how a human would use it rather than the digital on/off feel it has now. I suspect this will come with time.
boonedocks
MS LR Blk/Blk 19”
What you are describing is exactly the difference between TACC and EAP braking. You can place your toes, no shoes lol, under brake pedal and feel that TACC alone uses more regen before applying the brake and EAP snaps the pedal under the same conditions. Can't get anybody at Tesla to acknowledge. My SC even replaced the electro/mechanical brake booster tryin to fix it but it that not the problem since the behavior of different under EAP & TACC \i/
SeminoleFSU
Voluntaryist
I suspect this is going to be an easy fix for them... it's just a matter of tweaking the curves on how the brakes are applied and adjusting the thresholds and tolerances on the following distance to be a little more loose when closing the gap on traffic braking in front. Of course I make it sound easy- but in reality I wouldn't want to code that crap... my guess is all the dials are there to fine tune it, they just need to make the appropriate adjustments.. *fingers crossed* Maybe now that the fart app is out of the way they can get around to this 
SeminoleFSU
Voluntaryist
The fact that TACC and EAP have different braking behaviors doesn't give me a warm and fuzzy though in terms of them having a solid code foundation to build up from... Just that difference alone means parts that should have shared architecture still don't so it could be all ducked taped spaghetti code... I would imagine someone like wk057 or one of those really smart guys who have actually tinkered with AP code could tell us how good/bad it is.
boonedocks
MS LR Blk/Blk 19”
OR is it a single code base with branches but when EAP is added to the mix the APE just loses reaction time because of weak hardware/software causing it to react differently. There is a marked difference between the two and that's the part I can't get anyone at Tesla (that us mere owners can talk with) to even begin to understand.
SeminoleFSU
Voluntaryist
Yep definitely a possibility. I never use TACC but I'll do some experiments and see if my experience is the same.
SpudLime
Active Member
whoah, I never even noticed that for the same use case, TACC by itself or using EAP had different braking behaviors. Thats NOT good.
Nope, both TACC and autosteer were off. I do know what you're referring to though. Didn't happen at all today driving around, so who knows... just some random gremlins I guess.
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So I've noticed this same "thump" sound twice over the past week, except it just occurred once (not multiple times like I originally posted). Both times were after sitting at a stop light for about 10-15 seconds. It's not loud, but audible with the music low and I can feel the "thump" in the steering wheel and seat. It seems like it's coming from the front section of the car. Seems very random and no way to really duplicate it. Hopefully it's nothing, but would be curious if anyone else has experienced anything like this.
I am a newbie. Purchased S in March. While using TACC, when traffic suddenly stops, the brake pedal will vibrate and make a brief rattling noise. Tech Center tech says this is “normal “. Any way to poll this site to determine if everyone else experiences this, or just anyone else. I have read about things being replaced with no results; but I would really like to know what others have experienced, if anything. Any way to conduct a poll of owners?
RonaldT
RonaldT
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