Rumbling noise when decelerating at 5-12mph

[sheenn]

My 2017 S (delivery in March) has been in service 3x for this, and this last time for over a week and they still can't figure out what's wrong or make the sound go away. Basically when going very slow, either in parking lots, alley ways or even in bumper-to-bumper on the freeway on autopilot, I feel a low rumbling sound like the car is going over rumble strips. It's faint, but it's there and more consistently so now. It usually starts when decelerating (not quite regenerating/braking yet, but hovering over that neutral line) and not in response to road conditions. Though if I go over something bumpy, the sound will occur AFTER the bumps not while I'm going over the bumps. They've taken the steering column apart, they've replaced the struts, they've replaced the shocks, and it still makes the sound. Anybody experience something similar or have an idea of what it is?

I have to note I've driven several loaners during this time and NONE of them make a similar sound, though I have a coil suspension and loaners have air suspension and they think that may be why.

 

[bnsfengineer]

Have they looked at the drive unit?

 

[Tiger]

Maybe some tips here So much rattling....sigh

 

[daktari]

I might have the same issue, car has been in service for 2 weeks now.
I feel it as a dull rattle, when driving on uneven or patchy asphalt. Only audible in low speeds, more audible with windows closed. Some loaners, facelifts both ap1 and ap2, has had this. Not coming from bigger bumps.
They have changed same components as you (SAS on mine). SC mech boss has bought a new lift rack with "shakers" to reproduce.
I suspect maybe some internals inside the new Firestone air suspension units. Or maybe a heavy electric cable banging on some alu. Maybe we should get these SCs to have a chat?

 

[Sean Mitchell]

I may be having the same issue with mine - it's a very faint rattling sound. I've scheduled mine for service next week. Will see what they say.

 

[daktari]

Better have them check the "toolbox".
Mine is coming back without a fix for now. SC would not say what was wrong, but I got the understanding (my interpretation, not confirmed) that some changes are needed. Upper arms on front suspension is the culprit (also not confirmed).