How can the steering wheel centering be a software process?

[CFrolander]

So my car was in a wreck, it's been nearly four months now and I got it back once but there were slews of issues so I brought it back to the (tesla approved) shop to hopefully get everything right the second time around. One issue that it had was the steering wheel was WAY off! Like 15 or 20 degrees cocked to the left. The car didn't pull, it was aligned well, but you had to turn the wheel about 20 degrees to the left to make the thing go straight. It seemed to summon just fine, so the car clearly knew which way the wheels really were facing.

I searched for it online, and spoke with the tech at the shop, and I'm of the understanding now that it's possibly a software calibration to get this fixed? Back when I used to work on my cars, you could only get the steering this far off center by taking the wheel off the column and putting it back a number of splines off. According to the tech, the steering box can re-index itself via software somehow.

I guess two questions, for one is this true that the steering wheel center can be adjusted by software? And if yes, how does it physically work? It's not drive by wire, so I don't understand how it might reindex itself. My car didn't have to have any suspension components replaced at all, but the wheel and tire were because they got nicked, so I don't even quite understand how it could have gotten adjusted so far off.

2017 Model X by the way, though I assume they all have the same steering components

 

[compu85]

There is a software calibration to tell the car what the center point of the steering is - this is done after setting the mechanical centering. If the steering rack itself isn't centered (ie, the steering wheel wasn't centered when the tie rods were set up) it will negatively affect the steering geometry.

Unless there's some component of the steering rack I'm not understanding, the only calibration is to let the computer know what the mechanical setting is. Say with how the car is aligned straight ahead is 1* to the right on the steering wheel. The calibration tells the computer that 1* is center. Since the system uses the power steering motor to self center, this is important as the calibration being off can make the car feel like it's pulling.

It sounds like after the accident repairs, when they did the alignment they didn't have the steering wheel centered properly.

-J

 

[mxnym]

So my car was in a wreck, it's been nearly four months now and I got it back once but there were slews of issues so I brought it back to the (tesla approved) shop to hopefully get everything right the second time around. One issue that it had was the steering wheel was WAY off! Like 15 or 20 degrees cocked to the left. The car didn't pull, it was aligned well, but you had to turn the wheel about 20 degrees to the left to make the thing go straight. It seemed to summon just fine, so the car clearly knew which way the wheels really were facing.

I searched for it online, and spoke with the tech at the shop, and I'm of the understanding now that it's possibly a software calibration to get this fixed? Back when I used to work on my cars, you could only get the steering this far off center by taking the wheel off the column and putting it back a number of splines off. According to the tech, the steering box can re-index itself via software somehow.

I guess two questions, for one is this true that the steering wheel center can be adjusted by software? And if yes, how does it physically work? It's not drive by wire, so I don't understand how it might reindex itself. My car didn't have to have any suspension components replaced at all, but the wheel and tire were because they got nicked, so I don't even quite understand how it could have gotten adjusted so far off.

2017 Model X by the way, though I assume they all have the same steering components

I agree with this regardless:

It sounds like after the accident repairs, when they did the alignment they didn't have the steering wheel centered properly.

However, I saw a 2012 (yes, twenty-twelve) Cadillac CTS with a vibration in the steering wheel that was caused by a problem with a component used for automatic centering of the steering wheel (fixed under warranty), so it wouldn't be difficult to believe that a Tesla could do the same thing (actually center the steering wheel when it's not so far off). However, I'm guessing they don't, because I'd expect you to see errors of some sort with it being that far off.

That having been said, I would like to take a moment to inform you of a few minor issues in your OP:

1) If I understand the standard nomenclature correctly (and I should, I work for an automotive supplier), drive by wire simply means the accelerator pedal is not connected physically to the fuel system. Tesla is most certainly drive by wire, and you clearly meant steer by wire.

2) You know what they say happens when you assume... As it so happens, I have complained to the service center several times about the steering in my X, and it kept coming back fine. When I finally showed a technician the drastic difference between the steering in the loaner I had at the time and my Model X, said technician proceeded to attempt diagnosis again. At the end of the day, I was told (again) that mine is normal, and that, in fact, different Model X (model months?) do, in fact, have completely different steering components. IIRC, one had a Bosch rack, another had a different brand, and they allegedly weren't interchangeable.

ETA: Given that the Model X has the option to "vibrate" the steering wheel for LDW, and given that it feels like the steering wheel is turning back and forth slightly when this happens, it seems logical to assume there must be some level of software centering of the steering wheel, so perhaps it is only for that and doesn't involve sensors?