Registering TPMS IDs

Yes and no. Assuming the 2016 is the same set up as the gen 3.

The car will remember 5 tpms in the computer memory, as there is an optional space in the memory for a spare.
So you need to program the car to know the new 4 tpms sensors, requiring the dealer, (or a Techstream).
When you change out the tires, back to your summer tires, you have to change the tpms sensor ID's in the computer.

 

If you were planning to DIY swap your snows and regulars, don't want to be paying the dealership to do the handshake every fall and spring. you could just ignore the TPMS sensors in the snows. In other words just cut your losses. Or invest in similar equipment as the dealership, and the know how.

When I was in that situation I got regular, non TPMS valves with my snows, but that's in Canada: not sure how doable that is in the States.

 

Good point.
Does anyone know if the Gen 4 improved the TPMS set up over the Gen 3?

 

Congrats with your purchase! Would you please advise re what type of snow tires you've got?
I am also wonder if car computer can recognize the position each of TPMS is installed. So if I rotate the tire does it know which tire on front and rear.

 

That had been my observation too. At our level, it is just a list of 4 or 5 sensors. The computer receives pressure and temperature info but does not track the position. If any sensor transmits info outside the parameters, the computer tirns on the light, but does not tell you which one is at fault. The computer knows which one by serial number, but not by location.

Apparently, Toyota planned for an option to show details of each tire on the touch screen display, but it didn't make it to the cars yet. It's shown as an option in the owner's manual. But I haven't seen anyone comment that they have the option.

 

Would showing which specific tire is low increase complexity further, requiring a reset every time they're rotated? Checking the pressure of all four (to find which is low) is trivial, should be done regularly anyway.

 

IMO rotation does not require a reset for a registered TPMSs. System knows what pressure front and rear tires suppose to have and monitor accordingly.

 

Yes that's the case now. @Wolfman33 was speculating about revision to a system where the specific flat tire would be identified, and I was pointing out that increases conplexity involved.

 

The system has no idea what the pressures should be, it only goes on what pressure you have in each tyre when you initialise it and reports a loss from that pressure. It doesn't matter what pressure you put in each tyre, it remembers that pressure at the time of initialization. You could put 15 psi in one, 20 psi in another, 50 psi in another and so on and it will set that as the required pressure when you initialize.
When you rotate your tyres from back to front you should be re-adjusting the pressures, as they are different, then resetting the TPMS.
It doesn't know where each tyre is, as said above it just records the 4 sensors, no matter where they are on the car.

 

I do my own rotations, and early on decided to set all tires to the same pressure, 2~3 pounds higher than front tire spec. It doesn't seem to matter, saves the minor hassle of raising/lowering pressures.

Even if was following spec pressure I wouldn't bother resetting the TPMS: the front/rear diff is trivial, and I understand it takes something like a 25% drop to trigger a warning.

 

That's right. The car doesn't care where the TPMS is located. It compares the TPMS reported pressure to the initialization pressure.
For example, if you put tire "A" on the car with TPMS sensor ABC123. Fill the tire to 40 psi and re-initialize to establish the baseline pressure. (Follow the procedure involving reset button). The car doesn't care where the tire is located. All it cares about is that sensor ABC123 is reporting within 75% of that baseline pressure. If the tire reports 30 PSI or less, the light comes on. As long as it reports 31 PSI or more, the car is happy and it does not trigger the light.

Each tire has it's own baseline pressure in memory. You can reset the baseline yourself anytime you want. You don't need the Techstream for that. So if you want to change your pressures you can. Or if you want to use different pressures front and rear, you can.

For example if you want to run 40 front and 38 rear, put your tires on the car, fill them to the desired pressure, and reset the baseline.
Then 6 months later, when you rotate, the car doesn't know you rotated, so it's looking for 40 in the rear tires, (but it doesn't know they are on the rear) and 38 in the front, (but it doesn't now they are on the front) going by the serial numbers. You change your pressure in the tires by adding air or letting air out as needed. Then reset the base line pressures.

Example

ABC123 40 psi (happens to be on front) Min 30psi
ABC789 40 psi (happens to be on front) Min 30 psi
XYZ098 38 psi (happens to be on rear) min 28.5 psi
ABC456 38 psi (happens to be on rear) min 28.5 psi

The car doesn't know where the tire is, and doesn't care. You don't know the serial numbers and you don't care.

Reset the baseline using the reset button

The car is always looking for XYZ098 to be reporting 28.5 psi or higher (75% of the baseline 38psi) at 28.4 the light comes on, no matter where the tire is.

Then 6 months later you rotate.
the car still wants XYZ098 to be at 28.5 even though it's now on the back.

You let two psi out of the tires now on the rear to lower them to 38.
You add two psi to the tires now on the front to raise them to 40.

You reset the baselines.
the chart now would be:

ABC123 38 psi (happens to be on rear) Min 28.5 psi
ABC789 38 psi (happens to be on rear) Min 28.5 psi
XYZ098 40 psi (happens to be on front) min 30 psi
ABC456 40psi (happens to be on front) min 30 psi

Still the car doesn't know where they are, it is only going by serial numbers. And you still don't care about the serial numbers, since you set the pressure in the tires the way you wanted it and reinitialized.

 

If I correctly understood there are 4 (or 5) TPMS transmitters and only one signal receiver. This receiver (of unknown location) has pressure set point records associated with each TPMS ID.
IMO it would be beneficial to have 4 receivers. May be this is privilege of more expensive cars

 

Yes. At least that's exactly how it acts. If your light comes on, unless one tire is obviously flat, you have to check all 4 tires to see which ones are tripping the light.

It's my opinion that the car could keep track of the tire locations in the software, even with one receiver. You just have to have the option of telling the car where the tires are when you reinitialize it. I think Toyota went cheap at the last minute.

Personally, I think that there may be two receivers and Toyota chose not to implement a better software system. I am dealing with a failure right now in my car. My TPMS light comes on occasionally. And when it does, I check it with the Techstream and two sensors are out. Then the light goes out later, and all four sensors are reporting. It's both of my front sensors that stop reporting at the same time I don't think that's likely. So I think there is a receiver or at least an antenna in the front and another one in the rear, and in my case, the one in the front is failing. Of course, I don't know this, I'm just speculating. I have an appointment for the dealer to look at it in the near future. But it makes me wonder how Toyota set this up and why they didn't make work better for telling us which tire was low.

 

How long does it take to check all four tires, lol.

This is completely off track from the OP's question, btw.

 

I have my TPMS set up so that TP1 is front left, TP2 is front right, TP3 is right rear, and TP4 is left rear. So they are in clockwise order, starting with front left. When I rotate the tires front to back, they are counter clockwise starting with left rear. It's a bit of a game getting it set up, but once it is it's easy to use Techstream to identify which tire is a problem.

Before I set it up that way, I could tell by temperature and pressure which tire was which in Techstream. I run 42 pounds front, 40 back. So the two highest pressure tires with Techstream were front. And after parking the car sideways to the sun, the sun side showed higher temperatures. I verified my analysis by letting some air out one at a time, and seeing which tire changed in Techstream.

I was looking at a new Lexus in front of Costco the other day. It had "Location specific TPMS". Maybe it will trickle down to Prius some year...