PSA on TPMS and do you really need techstream to reprogram

[peniole]

This is a post as much for myself as well as my fellow members on our TPMS systems.

So as most of you know, our cars use TPMS sensors of the pressure sensitive (mounted in the tyre) masquerading as valve stems variety. Each sensor has a code that is printed on it and these codes are then programmed into techstream. You either have the simple system where you just have a TPMS light on your dash and are left having to check each tyre to find which one is low or you have a newer system where the tyre pressures are read out on dash. With the newer system you could also be left scratching your head as to which tyre is low if at some point the order of the tyres on the vehicle was mixed up (e.g. buying a new set of tyres and the wheel TPMS sesnor didn't go back to the same corner it was taken off). Frustrating isn't it?!

Let's start with techstream. Under TPMS in techstrem you have usually 4 (or 5 for vehicles with a full size spare) TPMS IDs listed in the system. The problem here is that they are just listed as ID1 through 4, no mention on which corner. Now ideally it should be according to Toyota USA (not sure if Japan or UK may be different):

ID1 = Front left

ID2 = Front right

ID3 = Rear right

ID4 = Rear left

So top view clockwise from front left to rear left. Sadly, a lot of mechanics/shops ignore this and things get screwed up. Also the car doesn't know which corner each TPMS sensor is on. It will just read them out onto the dash based on the above sequence. So if they've been swapped around, or they have been replaced, reprogrammed...etc. they could be out of sequence.

Now hopefully they aren't out of sequence and they are each on the correct corner. If one of them goes bad or reached end of life, you'll need to reprogram all of them in a set time (5 minutes) in techstream, assuming you have techstream, not just the one that's being replaced. Even worse, you have two sets of tyres, summer and winter, so you have to program each time you swap tyre sets. If you go down the techstream route, make sure to get the list of all sensors as shown above before you go into the reprogram screen, and most importantly make sure you write down the code of the new sensor before it is mounted on the tyre (or you'll need a read tool which I mention below). Here's a quick how to:

If you're OCD like me, and you rotate tyres and it bugs you that the pressures shown on the dash don't correspond to the correct corner, you'll also be doing a reprogram every tyre rotation. If you are availing yourself of the dealer service, which is what I do, one would hope they would do the same. Although speaking to one of the service managers, I think they might not bother. So you end up doing it yourself anyway.

 

There is also an alternative method without having to resort to techstream. you can buy a TMPS reader/writer (e.g. https://www.autelstore.co.uk/wholesale/autel-maxitpms-pad-tpms-sensor-programming-accessory-device.html) and programmable TMPS sensors (e.g. https://www.autelstore.co.uk/wholesale/autel-mx-sensor-2-in-1.html) or a combo (https://www.autelsale.co.uk/wholesale/autel-maxitpms-pad-sensor-mx-sensor.html) as replacements or even a whole set for winter tyres. You can program the whole new set with the same codes you have on your summer set, or just the one bad sensor you're replacing with the code from the sensor that failed. In either case no techstream programming needed. See following video for a quick how to on a relatively cheap reader/writer and programmable TMPS sensors:

 

I hope this helps those who are going through some TMPS problems, and myself when the time comes.

[Boxbrownie]

Interesting, but it does seem strange that if you get the valves mixed up during wheel/tyre changes the TPMS gets confused, surely the valve sensor sends the signal to the corresponding (nearest) receiver sensor at each corner of the vehicle, so the vehicle cannot get the wrong tyre information?

 

Every other car I’ve had with TPMS has never had this issue.

[peniole]

It's one antenna/receiver for the whole car, not one for each corner, and that's not just Toyota/Lexus. It's even sometimes combined with the key receiver in one module. My guess is you either got lucky or had good shops/mechanics who cared.

[Boxbrownie]

45 minutes ago, peniole said:

It's one antenna/receiver for the whole car, not one for each corner, and that's not just Toyota/Lexus. It's even sometimes combined with the key receiver in one module. My guess is you either got lucky or had good shops/mechanics who cared.

Nope….our present BMW and Range Rover both have TPMS and receivers at each corner, when changing a TPMS valve you just have to drive for about 10-15 minutes and the system recognises the new valve.

[peniole]

Since we're on a lexus/toyota forum, BMW's and Range's more complicated and error prone ($$$) systems did not come to mind.

Compare

to

 

[peniole]

Well after some more digging, looks like lexus have changed to the more complicated setup in recent years (when? 🤷‍♂️), including on my ES, where one can register an ID change and drive to complete initializaton. Thank you @Boxbrownie for making me dig deeper. So if you're lucky, or unlucky (time will tell), to have the newer system there's now two initialization modes for the system a "set pressure" mode and a "change wheel set" mode. Both accessible from the dash menus under TPWS. Older versions will just have initialize TPWS, equivalent to the set pressure mode and ID changes still require techstream or as outlined above.

[Guest]

Yes, the later system 2018 and on can self-register when it recognises a new unprogrammed sensor travelling with the car for long enough. I wish they came out with this about a decade earlier though. 

Interesting what you say about the original order, which is logical / clockwise. No doubt most tyre shops, especially with owners who tend to buy two tyres at a time, or unlucky enough to have regular punctures that required a new tyre altogether, it's highly likely that most of the Toyota / Lexus cars around have them mixed up. 

How do you know that they can all be re-programmed using the same, single ID serial code? Have you tried it and does it work okay - no issues or confusion from the single sensor?

I suspect as the car doesn't tell me which tyre is low anyway, that it's not such a big deal - as long as this works. I'd be tempted to do this if I have to do a DIY replacement on my wheels. And I might well need to do just that. 

[peniole]

Since I found that I had the newer version, never had to bother, sorry. Even after rotations, the system so far has been able to figure it out for itself.