How does an independent shop reset steering angle after alignment?

[todd2fst4u]

I just tried to change the wheel alignment because it pulled to the right, so remover the wheel to adjust it. I unplugged the power/cable to the wheel and after I mounted it back and its aligned. BUT autopilot, regenerative breaking, traction control, etc doesn't work I just drove 200 km and did a hard reset and its still not working. Any ideas? Just let it deep sleep till tomorrow and try again?

You should align the steering wheel by adjusting the length of the tie rods, not by removing the steering wheel.

 

[Killhaug]

You should align the steering wheel by adjusting the length of the tie rods, not by removing the steering wheel.

My mistake, sorry about that. The wheels are aligned, but the steering wheel is a bit off when the car goes straight. So i tried to fix this and it didn't work, but then I lost all function of AP, regen, etc like I posted earlier after i disconnected the power to the steering wheel.

 

[Dolemite]

My mistake, sorry about that. The wheels are aligned, but the steering wheel is a bit off when the car goes straight. So i tried to fix this and it didn't work, but then I lost all function of AP, regen, etc like I posted earlier after i disconnected the power to the steering wheel.

How do you know the wheels are aligned?

And you're generally supposed to disconnect all power to any vehicle when messing around with airbags - partly because crazy stuff happens, but mostly because of what you're experiencing now. On the TM3, that means disabling 12V power and high-voltage battery power - the former is in the frunk and the latter is under the rear seat on the right-hand side. It takes about 5 minutes. You could try doing this, letting the car "rest" for 45+ minutes, and reconnecting everything to see if the errors go away... but with my former BMW, if you made this mistake, you'd either 1) have to buy a special OEM or aftermarket "software" tool to reset the airbag light, or 2) go to the dealership to have them reset it for you. Given Tesla's attitude towards DIY & aftermarket in general, you may end up having to go to the service center. I'd be curious to know how it goes.

 

[Pyre]

From what I have gathered [correct me if I am wrong please]:

1) Get car aligned anywhere.
2) Drive 30+ miles anywhere.
3) Let vehicle enter deep sleep: (make sure sentry mode is OFF and turn standby mode OFF. Do not look at vehicle via app).

Number 3 should reset steering angle sensor. I.E. if your car does not pull one way or the other when driving but your steering wheel is off center the system will correct?
I do not know how long vehicle must enter deep sleep mode for.

I have not tried this, just compiling data for an assumption.

 

[Pyre]

Edit: for steering wheel sensor alignment/reset a Tesla employee stated Tesla's need to be in "service" mode. And to be in "service" mode the vehicle has to be in a 'geofenced' area such as Tesla service center.

So in a sense, set steering wheel straight, align car, should not have an issue.

 

[Aggmeister2010]

I.E. if your car does not pull one way or the other when driving but your steering wheel is off center the system will correct?

If your car pulls one way or another, your camber, caster or toe values are not set right. If your car goes straight but your steering wheel is off-center, the tech likely didn't get it perfectly centered and settled before he/she started. Could be as easy as front toe-shift to one side or the other.

Alignment is a mechanical process, Period. The system can't "digitally correct" for the mechanical linkages not being set right. Steering angle sensor is just a magnet on a wire - it only tells the car what angle the steering wheel is at, nothing else. It's not making any corrections for how that steering wheel connects to the rack, because it can't.

If you'd like, I can share my 'ideal' alignment spec that I have my car set to. It can be performed by anyone with an alignment rack.

 

[gearchruncher]

It's not making any corrections for how that steering wheel connects to the rack, because it can't.

The rack on a Tesla is electric. It's just a few lines of code for the steering sensor to impact what the rack treats as centered and provides assist from that position.

I used to think this was highly unlikely too. However, I do my own alignments, and have absolutely observed my car pulling to one side when the wheel is released, however, if the wheel is held dead straight, the car goes straight. The alignment is right. The assist is off. This fixes itself after just a few miles. This only happens if your alignment was off before however... Like it was trying to correct for it.

Anyway, I'm now a believer something funny can be going on, so you have to give it some time. The correct check is if it pulls when the wheel is centered, not when the wheel is released.

 

[Aggmeister2010]

The rack on a Tesla is electric. It's just a few lines of code for the steering sensor to impact what the rack treats as centered and provides assist from that position.

I used to think this was highly unlikely too. However, I do my own alignments, and have absolutely observed my car pulling to one side when the wheel is released, however, if the wheel is held dead straight, the car goes straight. The alignment is right. The assist is off. This fixes itself after just a few miles. This only happens if your alignment was off before however... Like it was trying to correct for it.

Anyway, I'm now a believer something funny can be going on, so you have to give it some time. The correct check is if it pulls when the wheel is centered, not when the wheel is released.

Electronic Steering Assist =/= Drive By Wire.

The only difference between a Tesla rack and one from, say, a cChevy Tahoe is that the Tahoe’s is assisted via a belt-driven pump. Tesla’s rack is electric in the sense that the power steering pump is electric, because it has to be. But the input to the rack is still “manual” via linkages to the steering shaft and up to the steering wheel. You can see it yourself if you take the drunk tub out.

The situation you describe in the second paragraph is caused by a bad alignment. I experienced the same thing, and it was caused by ever so slight incorrect front toe and cross-caster. After more adjustments, it was resolved…no sensor corrections were involved.

It can feel like the car is “adjusting” as you go down the road because the slope of the road can change ever so slightly lane-to-lane or mike-by-mile, and that’s more than enough to cause a car to drift or balance out a bad alignment to make it feel like it’s going straight.

 

[gearchruncher]

The only difference between a Tesla rack and one from, say, a cChevy Tahoe is that the Tahoe’s is assisted via a belt-driven pump. Tesla’s rack is electric in the sense that the power steering pump is electric, because it has to be. But the input to the rack is still “manual” via linkages to the steering shaft and up to the steering wheel. You can see it yourself if you take the drunk tub out.

As someone that generally drives the car around without the frunk liner in due to working on the suspension constantly, I am well aware that a mechanical connection exists and it's not drive by wire.

However, it's easy to realize your analogy is wrong and the Tesla is much more complex. The Tesla rack has a CAN bus connection, because the Tesla rack can drive the car by itself as part of the AP system. It is nothing like a Tahoe rack. It has no mechanical center. It is quite feasible for it to calibrate itself, and for it to create a return force to an arbitrary point.

It can feel like the car is “adjusting” as you go down the road because the slope of the road can change ever so slightly lane-to-lane or mike-by-mile, and that’s more than enough to cause a car to drift or balance out a bad alignment to make it feel like it’s going straight.

As I mention, I do my own alignments. I've driven the same road, same lane, in both directions, and the car goes dead straight if the wheel is straight. It pulls to the same side if you let go of the wheel, reliably. 10+ miles later, it does not do this.

As I say, I was a skeptic too, having never experienced this before. Go tweak your own alignment and give it a shot. An eighth turn on each tie rod. The car will eventually learn this non-straight wheel angle as the center of the rack.

 

[Aggmeister2010]

Ok, so let me make sure I'm hearing you right. I know that the steering angle sensor can 'learn' - If it didn't, then a misaligned car might shoot off in one direction or another when you activated AutoPilot, because it wouldn't know where 'center' was.

But given that it's still a mechanical linkage, it can't "magically" change your camber/caster/toe values to make a misaligned car drive straight. It can learn that "steering wheel 3 degrees clockwise is as straight as i can get," but if you want a perfectly centered steering wheel that goes perfectly straight, you'd need two wrenches and a rack.

Correct?

BTW, yes, the Tahoe example was over simplistic - the point I was trying to make is that it's not a wizard-rack that can self heal. But from what you're saying, it sounds like it can use input from the steering angle sensor to let the Electronic Assist Module actively 'hold' the wheel in a particular position to keep the car moving pretty straight. So, addressing the symptoms electronically, but can't address the actual cause without adjusting camber/caster/toe.

 

[electricar]

As someone that generally drives the car around without the frunk liner in due to working on the suspension constantly, I am well aware that a mechanical connection exists and it's not drive by wire.

However, it's easy to realize your analogy is wrong and the Tesla is much more complex. The Tesla rack has a CAN bus connection, because the Tesla rack can drive the car by itself as part of the AP system. It is nothing like a Tahoe rack. It has no mechanical center. It is quite feasible for it to calibrate itself, and for it to create a return force to an arbitrary point.



As I mention, I do my own alignments. I've driven the same road, same lane, in both directions, and the car goes dead straight if the wheel is straight. It pulls to the same side if you let go of the wheel, reliably. 10+ miles later, it does not do this.

As I say, I was a skeptic too, having never experienced this before. Go tweak your own alignment and give it a shot. An eighth turn on each tie rod. The car will eventually learn this non-straight wheel angle as the center of the rack.

Is the Tesla rack variable ratio? If so wouldn't that mean there is a mechanical center or is the effect created with mechatronics?

 

[Dolemite]

As someone that generally drives the car around without the frunk liner in due to working on the suspension constantly, I am well aware that a mechanical connection exists and it's not drive by wire.

However, it's easy to realize your analogy is wrong and the Tesla is much more complex. The Tesla rack has a CAN bus connection, because the Tesla rack can drive the car by itself as part of the AP system. It is nothing like a Tahoe rack. It has no mechanical center. It is quite feasible for it to calibrate itself, and for it to create a return force to an arbitrary point.



As I mention, I do my own alignments. I've driven the same road, same lane, in both directions, and the car goes dead straight if the wheel is straight. It pulls to the same side if you let go of the wheel, reliably. 10+ miles later, it does not do this.

As I say, I was a skeptic too, having never experienced this before. Go tweak your own alignment and give it a shot. An eighth turn on each tie rod. The car will eventually learn this non-straight wheel angle as the center of the rack.

But from what you're saying, it sounds like it can use input from the steering angle sensor to let the Electronic Assist Module actively 'hold' the wheel in a particular position to keep the car moving pretty straight. So, addressing the symptoms electronically, but can't address the actual cause without adjusting camber/caster/toe.

That's right - I've noticed this, too. The car seems to actively monitor your correction inputs & then assist in some way/shape/form. I fixed some shitty alignment the other day & the car kept wanting to pull to the right when I let go of the wheel. But holding the wheel straight kept the car going straight. After some amount of time, letting go of the wheel no longer made it veer off to the right.

But in essence, it's correct that the #1 thing you should care about is the alignment being as mechanically perfect as possible. Can't use software to correct low-quality work in the analog world (said nobody at Boeing).

 

[gearchruncher]

So, addressing the symptoms electronically, but can't address the actual cause without adjusting camber/caster/toe.

It's possible to have perfect overall toe, caster, and camber.,but have the wheel not centered. It just means your toe is offset on both sides the same.

The rack appears to learn this. All it is solving is where the center assists to. The issue is if you bend something, then drive around, it learns a new center. You then align it right, and go test drive. Your customer takes their hands off the wheel, and it pulls to one side. This is because the rack is actively driving off center as it doesn't know you re aligned. But it figures it out really fast.

 

[gearchruncher]

Is the Tesla rack

No Tesla rack is variable ratio, only variable assist.
Even famously on the new, complely stupid yoke card, it's fixed ratio.
Yes. Really.

 

[Aggmeister2010]

It's possible to have perfect overall toe, caster, and camber.,but have the wheel not centered. It just means your toe is offset on both sides the same.

The rack appears to learn this. All it is solving is where the center assists to. The issue is if you bend something, then drive around, it learns a new center. You then align it right, and go test drive. Your customer takes their hands off the wheel, and it pulls to one side. This is because the rack is actively driving off center as it doesn't know you re aligned. But it figures it out really fast.

Exactly. I've found over the years that quick in-and-out alignment shops (and Tesla SCs) don't do a stellar job of getting the steering wheel perfectly straight before they start. So I've had several cases of "all in the green," but the wheel is off-kilter a few degrees. It's always funny to me how many folks say to "take the steering wheel off and move it a tooth or two." No way, just shift your total toe a bit.

 

[Dolemite]

Exactly. I've found over the years that quick in-and-out alignment shops (and Tesla SCs) don't do a stellar job of getting the steering wheel perfectly straight before they start. So I've had several cases of "all in the green," but the wheel is off-kilter a few degrees. It's always funny to me how many folks say to "take the steering wheel off and move it a tooth or two." No way, just shift your total toe a bit.

They just care about getting it "in da green." If you want a perfect alignment, you've gotta pay for it or DIY it. The laser machines they use also aren't that precise. Nothing beats strings & patience.

 

[gearchruncher]

To revive this thread because it came up in another place...
You can now go into the service menu and see the steering wheel angle via the sensor on the screen. So you can actively turn the wheel to 0.0° and then align from there. A much better way to zero everything out.
You can even teach it a bias in there if for some reason you wheel and the sensor are not well aligned.

 

[TacoSteve]

They just care about getting it "in da green." If you want a perfect alignment, you've gotta pay for it or DIY it. The laser machines they use also aren't that precise. Nothing beats strings & patience.

This is half true. Yes, most big alignment shops only care about getting in the green, but laser alignment machines are incredibly precise. It's the user of the machine that doesn't care about getting precise alignment settings. String is fine, but a Laser alignment machine is going to give you more accurate readings.

Source: I've done my own string alignments for years and now operate a Hunter Elite Laser alignment machine. Mostly aligning Tesla's.

 

[gearchruncher]

String is fine, but a Laser alignment machine is going to give you more accurate readings.

I looked all over and couldn't find any accuracy specs on Hunter machines, which is odd for a measurement device. Do you have data on what they actually achieve in real use?

 

[TacoSteve]

I looked all over and couldn't find any accuracy specs on Hunter machines, which is odd for a measurement device. Do you have data on what they actually achieve in real use?

I was present during the calibration process. They calibrate to .005 degrees, but most specs are in increments of .01 degrees with an accuracy of + or - .15 degrees.