Do P85Ds and S85Ds have inaccurate odometers that overstate distance traveled?

[Cyclone]

Andy,

Any chance this was addressed by firmware, but takes a tire switch to "trigger" a reset? Something like they found the bug, but it won't change the active runtime parameters until the wheel configuration is reset. Maybe even a TPMS reset would do this? I'm speaking out of my rear, but a plausible scenario if your "fix" was truly just a software fix.

 

[Andyw2100]

Andy,

Any chance this was addressed by firmware, but takes a tire switch to "trigger" a reset? Something like they found the bug, but it won't change the active runtime parameters until the wheel configuration is reset. Maybe even a TPMS reset would do this? I'm speaking out of my rear, but a plausible scenario if your "fix" was truly just a software fix.

This sounds plausible to me, based on my limited knowledge of how this stuff works.

All I know for certain is that my numbers are definitely different now, and closer to reality by about what everyone estimated them to be off by, while others' odometers are still off. My wife's trip to work today was the exact same length, to the tenth of a mile, as the last one I reported--53.4 miles. (Edit: Same for the trip home--52.8 miles, just like the last one.) I am 100% sure that our P85D's odometer is now reporting mileage differently than it had been before, and that what it is reporting now is much closer to the actual mileage driven.

I guess we just have to wait for others to change their tires or reset their TPMS to see if other people start seeing similar changes in their odometers' behavior.

Thanks for coming up with that theory!

 

[wk057]

Finished my latest ~1200 mile trip. For all legs of the trip where I followed the same route as last time, the trip meters matched the previous trips to within +/- 0.1 miles.

 

[skilly]

In general all vehicles track slightly more speeds to the driver than in reality but the odometer readings should be accurate baring any wheel configuration changes made outside of factory defaults.

 

[Andyw2100]

In general all vehicles track slightly more speeds to the driver than in reality but the odometer readings should be accurate baring any wheel configuration changes made outside of factory defaults.

Please read some of the early posts in this thread.

We have pretty well established that the Ds' odometers are overstating distance traveled by about .8%, in a way previous Tesla Model S vehicles had never done before.

The recent posts are because I mistakenly thought this was corrected via firmware, after my car came back from the service center and a recent firmware update providing lower mileage numbers for the exact same trips I've been charting for months. It turns out I was mistaken, and either the changes were made, for now, just to my car, or they were made via software, but require a wheel change or TPMS reset or both before they are implemented. Until someone else confirms that they too are now seeing more accurate numbers (when they were not before), and can then say what they did to achieve them (TPMS reset, wheel change, etc.) we won't know exactly what's going on.

 

[Thud]

SAE allows for up to 4% margin of error on odometer readings. Tire pressure and tire wear can affect those readings.

 

[Andyw2100]

SAE allows for up to 4% margin of error on odometer readings. Tire pressure and tire wear can affect those readings.

Really? That's just so very helpful.

Yes, the above is a sarcastic response. I'm sorry, but when a thread is so far beyond information like the above, and a poster just pops in and feels the need to post, without so much as reading some of the thread to see if what he or she has to say is relevant, I think a little sarcasm is called for.

The poster might argue that the thread is already nine pages long, and he or she didn't want to bother to read it. Fine. Then don't. But then perhaps think twice before posting something incredibly obvious that it is likely everyone discussing the subject already knows. And if you decide to post your nugget of wisdom anyway, expect it to be met with sarcasm.

Would you jump into the middle of an ongoing conversation at a party, without knowing what has been talked about, and blurt out some random fact? If not, then why do essentially the same thing here?

 

[myms]

Really? That's just so very helpful.

Yes, the above is a sarcastic response. I'm sorry, but when a thread is so far beyond information like the above, and a poster just pops in and feels the need to post, without so much as reading some of the thread to see if what he or she has to say is relevant, I think a little sarcasm is called for.

The poster might argue that the thread is already nine pages long, and he or she didn't want to bother to read it. Fine. Then don't. But then perhaps think twice before posting something incredibly obvious that it is likely everyone discussing the subject already knows. And if you decide to post your nugget of wisdom anyway, expect it to be met with sarcasm.

Would you jump into the middle of an ongoing conversation at a party, without knowing what has been talked about, and blurt out some random fact? If not, then why do essentially the same thing here?

...relax?

 

[Andyw2100]

...relax?

Eleven posts in almost two years before this one. I guess I should be honored.

I'm pretty relaxed. I just find the action taken by the poster I was responding to pretty darn rude, and completely unhelpful.

 

[duncanduncan]

Really? That's just so very helpful.

Yes, the above is a sarcastic response. I'm sorry, but when a thread is so far beyond information like the above, and a poster just pops in and feels the need to post, without so much as reading some of the thread to see if what he or she has to say is relevant, I think a little sarcasm is called for.

The poster might argue that the thread is already nine pages long, and he or she didn't want to bother to read it. Fine. Then don't. But then perhaps think twice before posting something incredibly obvious that it is likely everyone discussing the subject already knows. And if you decide to post your nugget of wisdom anyway, expect it to be met with sarcasm.

Would you jump into the middle of an ongoing conversation at a party, without knowing what has been talked about, and blurt out some random fact? If not, then why do essentially the same thing here?

+1 !

 

[GSP]

Tesla stated they are within the allowed error per the SAE industry recommended practice. It is helpful for us to know how much error is allowed. It informs us all. Clearly owners posting here would like better accuracy than just 4%, but that is another story.

Personally, I prefer Tesla to concentrate on the new paint shop, the new body shop, Model X launch, installing more Superchargers, the Model III design, and getting the Gigafactory running smoothly before they run out of cash to pay for all of these high stakes investments.

It is good to know about the odometer differences and to notify Tesla. That work also informs us all, so thanks for that as well.

GSP

 

[Andyw2100]

Tesla stated they are within the allowed error per the SAE industry recommended practice. It is helpful for us to know how much error is allowed. It informs us all. Clearly owners posting here would like better accuracy than just 4%, but that is another story.

I'm thinking you probably haven't read the whole thread either. If you have, and it was some time ago, I'll remind you of a couple of salient points:

--The Ds are the first models where this is any kind of an issue. Other Model S vehicles had odometers that were much more accurate, and provided the expected figures.

--With all the Ds off by about the same amount, it appeared to us that the problem could be as simple as a bad formula or calculation somewhere. There wasn't variance within the odometers, with all of them reporting wild figures somewhere within 4% of the correct figure. All the D odometers were reporting mileage about .8% longer than it actually was. This is precise and accurate--just wrong.

--Tesla has now corrected the issue on my car. For now, I have the only known car with the fix, but that's probably because I'm the only one who has noticed it. One theory is that the fix has been made in software, but needs a TPMS reset and/or a wheel change to be activated on the car. Another possibility is that the fix somehow has to be taken care of while at a Service Center, as my car was at a SC just before the odometer started reporting accurate mileage, but I don't think this is likely, as there was no documentation on my work order about this.

I think we can stop talking about whether the problem is real or not, who it matters to and why, SAE standards, etc. (since that's all been done before) and at this point just focus on whether or not other vehicles are receiving the fix, and if so, what it takes to trigger it.

 

[MarcG]

--Tesla has now corrected the issue on my car. For now, I have the only known car with the fix, but that's probably because I'm the only one who has noticed it. One theory is that the fix has been made in software, but needs a TPMS reset and/or a wheel change to be activated on the car. Another possibility is that the fix somehow has to be taken care of while at a Service Center, as my car was at a SC just before the odometer started reporting accurate mileage, but I don't think this is likely, as there was no documentation on my work order about this.

Andy, have you asked your SC for more information about what they did and discussed this issue in detail with them? I found my SC to be very helpful and fairly knowledgeable, and when they don't have an answer to my question, they go out of their way to find it out.

 

[Andyw2100]

Andy, have you asked your SC for more information about what they did and discussed this issue in detail with them? I found my SC to be very helpful and fairly knowledgeable, and when they don't have an answer to my question, they go out of their way to find it out.

I had not, because there was no mention of it on the printout of the work they did that I received, and frankly I didn't want to make them go digging into this for me. But there's really no reason this should be a big deal for them, so I did just write to the service advisor who had been working with me. I'll report back when I hear back.

 

[Andyw2100]

I just posted an update in the thread where I'm trying to collect some data: Some assistance needed from brand new D owners with simple data collection

I'll include some of the relevant information below.

I'm going to report some data myself, and then explain why, and what I think it might mean.

On Friday I took a trip from Syracuse to Rochester and back. (The trip back is shorter because I stopped at the Syracuse supercharger and only tracked the mileage to that point.) Below is the data for the two "trips", including four different start and end points.

Model: P85D
Delivery Date: December 24, 2014
Current Firmware version: 6.2.2.4.236
Firmware version at time of delivery (if known): Irrelevant

Odometer Mileage	Actual Mileage	Difference	%	Source (Actual Mileage)
94.6	93.75	0.85	0.907	Mapquest
82.7	81.99	0.71	0.866	Mapquest

So...what do I think the above means?

Well, it would appear that my odometer actually is still overstating the actual mileage, and by very close to the exact amount--.8% or so--that people seemed to think the odometers were off by before. In that case, how do I explain my earlier theory that the problem had been corrected?

The 50-60 mile trips I had been recording --WERE-- being recorded by the Model S as being shorter than they had been, by a few tenths of a mile. I'm now thinking that with my snow tires on, my odometer (and presumably all D odometers, or at least the early ones) was overstating mileage by substantially more than that .8%. I had never attempted to quantify how much my odometer was overstating the mileage by. It was others who came up with the .8% figure. I couldn't quantify my overstatement because of the length of my driveway, my wife driving around the parking lot at the other end of the trip, etc. I just knew that even with those distances added in, the mileage had to still be overstated. After my car came back from the service center with the all-seasons on, and with the software update, the overstatement amount came down by very close to that .8% figure. I'm now thinking that I very well may have reached the wrong conclusion that Tesla had corrected the problem, when in actuality, the problem is just worse with snow tires on.

Sorry for the false alarm, if that's what my thoughts that the problem was resolved turn out to have been.

 

[WarpedOne]

Really? Three pages about 0,8% error in odometer overshoot? Really? And hinting at conspiracies?
Internet forums ..

Odometer is a simple device - it counts wheel revolutions. Those revolutions are then multiplied by some magic number and the result is shown on the dash. Same measurement is used to calculate current speed. Regulations mandate that actual speed must never be higher than displayed, it can be lower by some X percent, but never higher. Never ever.
How one gets distance into revolutions? By rolling the tires that have varying diameter depending on everythig. A bit higher temperature? A radius may be smaller or higher, a bit higher load? A radius will be a bit smaller etc. New tire has up to half an inch bigger circumference than a worn one.
All those variations together must still never result in actual speed above displayed. So manufacturers that don't have magic at their disposal err on theirsafe side - they reserve some margin off error to warrant displayed speed is never lower than actual.

Go calculate tire circumference for homologated tires, they differ up to 2%. Did anyone reprogram new diameter when he switched tires? Did anyone reprogram new radius when he took a passenger?

Sometimes I just don't get people that earn enough for such cars but at same time they have so little common sense.

 

[Zythryn]

...
How one gets distance into revolutions? By rolling the tires that have varying diameter depending on everythig. A bit higher temperature? A radius may be smaller or higher, a bit higher load? A radius will be a bit smaller etc. New tire has up to half an inch bigger circumference than a worn one.
All those variations together must still never result in actual speed above displayed. So manufacturers that don't have magic at their disposal err on theirsafe side - they reserve some margin off error to warrant displayed speed is never lower than actual.

Go calculate tire circumference for homologated tires, they differ up to 2%. Did anyone reprogram new diameter when he switched tires? Did anyone reprogram new radius when he took a passenger?

Sometimes I just don't get people that earn enough for such cars but at same time they have so little common sense.

Common sense would say that variations in tires would lead to variations both above and below the norm.
The issue people are curious about is that;
the error seems to be extrordinarily consistent,
the error is in the opposite direction one would expect of new tires,
the error was not present in earlier cars.

As for common sense, these are very good questions.
It is a puzzle, and people like solving puzzles. If it were a random distribution I doubt it would be found such an interesting mystery.
It is especially an interesting puzzle for engineers and math/data geeks, of which there are a fair amount of here.

 

[WarpedOne]

Common sense would say that variations in tires would lead to variations both above and below the norm.

I explained why it aint so: regulations mandate it must not ever undershoot the current speed, no matter the variations in tire dimensions, pressure, loads, speed etc. Higher speed results in a bit bigger tire radius and hence lower range measured.

If it undershot, it would also display lower speed than actual. Such a vehicle is unfit for public roads and would not get permit to sell as such.
Hence there are built in margins that err on the other side - overstating the driven distance and overstating the the speed.
The error can be bigger or smaller, but it must never be negative. Actually 0,8% is a miniscule amount of safety margin. Standards demand less than 4% error on the overshoot side, and 0% error on the undershoot side, no matter circumstances.

 

[Zythryn]

...
.
Hence there are built in margins that err on the other side - overstating the driven distance and overstating the the speed.
The error can be bigger or smaller, but it must never be negative. Actually 0,8% is a miniscule amount of safety margin. Standards demand less than 4% error on the overshoot side, and 0% error on the undershoot side, no matter circumstances.

Sorry, haven't had my coffee yet.
Yes, that would make some sense, in which case the earlier situation in which the Odometer was right on target gave too small a margin of error.
I've never heard of that requirement for speedometers, however that makes some sense.

It still doesn't mean seeing a difference in the car's readings, and systematically experimenting to try to explain it is indication of lack of common sense.
To me, it is the epitome of logic and the scientific method and should be applauded.

 

[Andyw2100]

Sometimes I just don't get people that earn enough for such cars but at same time they have so little common sense.

And I never understand people who feel the need to insult groups of people because the discussion they are having doesn't seem interesting enough or relevant to the person doing the insulting.

I explained why it aint so: regulations mandate it must not ever undershoot the current speed, no matter the variations in tire dimensions, pressure, loads, speed etc. Higher speed results in a bit bigger tire radius and hence lower range measured.

You haven't explained why this error exists now, in the Ds, when it never existed in earlier Models Ss. But please go ahead and do that. I'm sure we'd all be interested. If you can't do that, how about you take your insults somewhere else?