Replaced TPMS sensors, but tire shop says couldn't connect via OBD

Do you know what scan tool they were using? I recently picked up a Launch CRP129E because it was on sale, but it can't connect to my wife's Prius. Completely current on all updates, it can't read the VIN, and can't even connect manually. It has no problem connecting/reading my Tacoma or my daughter's Civic.

Everything else I have - Autel DS808, Bluedriver, and VeePeak - have no problem connecting/reading the Prius, with the Autel having no problem with bidirectionals.

I'm pretty sure it's a Launch software thing, but don't know if it extends to other Launch scan tools. The 129E is pretty 'up there' in their line without having bidirectional (though you can pay extra for certain functions).

 

Did you write down (or photograph, or anything) the ID numbers on the new sensors? You need those for registering the new sensors to the car, and they are hard to read once installed in the tires.

I just went through this yesterday and was thinking of writing it up anyway. I was using Techstream with a dongle from Tactrix, on a 2010.

I had just one sensor go out. It's been twelve years, so probably there are more in my future, but in the name of science, I'm willing to wait and see how spread-out the failures are. So I've just replaced the one that went out, so far.

When I bought the car, I read (with Techstream) the IDs of all four sensors, and figured out (by letting air out one tire at a time) which one was in which tire. I put that information in a file that I update when rotating tires, so I always know which ID is at which corner of the car. So as soon as I got the blinking-then-steady TPMS light, I was able to connect Techstream and see which ID wasn't transmitting, and know it was the front right tire.

So I bought one new sensor, and programmed its ID into the car first, and then went to my usual Discount Tire and said "how much to put this sensor in my RF tire? I already registered it with the car" and over the phone they said $10 but when I got there they did it at no charge.

When I (pre)-registered the new sensor with the car, using the Tactrix dongle, it went like this:

• The registration utility wipes all 4 existing IDs, so you need to enter all 4.
• So I used my file of the original IDs, changed the front right to the new ID, and entered all 4 of those.
• After entering the 4th one, the utility sits for a second or so, then reports an error, and suggests canceling the registration and trying again.
• But returning to the TPMS Data List page shows the correct IDs got registered, and the trouble codes page then shows only C2126, which is the expected code for "you just registered some sensors and I'm waiting for their signals". So the reported error seems to be something harmless after the important stuff happened.
• The new sensor doesn't seem to transmit until it is actually in a tire with pressure (I even laid it for a few minutes on the RF tire to see if it would be picked up, but no). So after the (pre)-registration, the C2126 code remains until the sensor is really installed and the inflated tire is back on the car.
• After the receiver has heard from all 4 sensors, the C2126 code goes away by itself. But the tire light stays on, for some reason, even though Techstream shows no trouble codes. Even after turning the car off and back on, the tire light will still be on, even though Techstream still shows no codes.
• Running Techstream's TPMS Signal Check utility (just clicking next through the various steps) makes the light go out (even though, just like the registration, this utility pops up an error box at the very end).

So that seems to be pretty much how it goes with Techstream and a Tactrix.

In my real story yesterday, it didn't go exactly that way, because the Discount Tire guys did more than I asked them to. Even though I told them I had already registered the new sensor, I was watching through the glass as the guy unplugged my Tactrix, plugged in his own gizmo, and re-registered all 4 of my tires for me, then plugged my Tactrix back in and gave me the car back.

Those guys have a handheld receiver that can snoop the IDs of transmitters inside tires, which is how his gizmo was able to re-register all 4 IDs when they couldn't see into the other 3 tires.

So, before driving away, I connected with Techstream again, and of course all 4 correct IDs were in there, but in a different order than I had in my file. So I ran the registration utility again and put them in the order I had. Naturally, that put up the C2126 code again, but by my next stop on the way home, the code had gone away, and I could run the signal check utility to make the light go out.

Sooner or later, I suppose the next one will go. I'll probably go back to Discount Tire for the mounting work (can't beat that price!), but maybe I'll try telling them "no, really, I've already registered the new ID...".

 

What's your build-date Chap? Ours is August '09, and they're all still fine. The OEM wheels (with the sensors) sit in a stack in the garage for upwards of 5 months a year, while the car's on snow tires; not sure if that's a factor.

If and when they die I'll likely just ignore them. Canada's more lax than the States though, no inspection concerns.

 

The thing is, whenever a "they" tells you they couldn't connect to an ECU, sometimes you don't know much more until you try it and see what happens. All I know is what happens with Techstream, which is a little weird with the error dialogs and such, but eventually seems to get the job done. If you're trying with something other than Techstream, have you found any info on whether it normally should be able to do TPMS stuff, or not?

March 2010 here. I don't think I've got inspection concerns here either, but oddly enough, I like having the system. I set mine to warn just a couple psi below my preferred pressures (the ordinary setting only warns for "way too low"), and combined with an air source on board, it makes maintaining the pressures I prefer really easy.

Whether the transmitters are "still fine" seems to be a kind of binary proposition. There is a battery-voltage item for each sensor that you can see in the Techstream data list, but as far as I can tell, it just says "over" until the day the sensor stops transmitting.

 

The DS808 can push TPMS IDs to the ECU (as well as read what's currently in there). Can't get the CRP129E to connect even manually drilling down - always says there's no connection.

I have an ATEQ VT36 that I've never used on the Prius (have only used it on a Nissan and Buick - because never needed it otherwise). If I recall, when you use it to trigger a read, it came back with the ID, frequency, current pressure, temp (if available), and for battery, it would just say "OK" (no level - don't know what it would say if the battery is dead/bad). It can also clone IDs to various brands of programmable sensors. It can't push IDs to the ECU like the more expensive models, but I have the DS808 anyway.

ATEQ also has a tool called Light TPMS Reset Tool for less than a $100 that can push ID's to the ECU. The quirky thing about it is it can't READ sensors, so you have to know the IDs to use it (I believe). It's mostly used by people to swap Summer/Winter tires. There was also some quirk in that it limited how many IDs you could store.

https://www.ateq-tpms.com/en-us/products/quickset-light-tpms-reset-tool/

 

Autel 508 would be able to complete the job if the sensors they installed are compatible for the car.

 

From the "weird enough for you?" department:

Today, my tire light was on again. And there were no TPMS codes. So, it was like the situation from yesterday, where there was the C2126 right after registration, but it went away as soon as all the sensors checked in, but the light stayed on.

Going through the Signal Check utility in Techstream had turned the light off yesterday, but for whatever reason, today, it was back. And along with having no trouble codes, everything in the Data List looked perfectly right.

Just for grins, I dug out the Mini VCI dongle. I ordinarily prefer the Tactrix for everything on this car. But there were those strange error dialogs I was getting after registration, and after signal check, though it still seemed like the right stuff all happened.

With the Mini VCI, when I run the Signal Check utility, I think it goes further. (I might have to go back and shoot videos and compare.) It did enter test mode with the blinking tire light, as described in the manual, and I don't remember getting that far with the Tactrix.

When I exited the test mode, the light was off again, and (so far, after a couple power cycles) seems to be staying off.

 

Today the light has stayed off.

 

Can any computer disable the TPMS system enough so that the light will just stay off like make it so the car doesn't have TPMS without taking the dash apart and removing the LED?

 

I'm about to buy one of these aftermarket TPMS computers reset devices they're really cheap now they don't really need the car's computer apparently they use the bandwidth of your car's TPMS system to communicate with it like 112 megahertz or whatever it is and does it that way and it's pretty automated is no complicated bunch of nonsense going on apparently using the text stream seems more cumbersome than using these newer things that are pretty cheap 30-40 bucks or something and some of the newer TPMS sensors are programmable on the fly like a box of four might cost $45 I just bought a set I haven't fooled with them yet but they come with extensive instructions and are supposed to be pretty easy to work and reset possibly on or off the car apparently these I can push the little button and turn them on without having them be inside of a tire with pressure

 

IIRC, for Gen2 (or was it for Gen3?), there is a way to short out the TPMS ECU pin to disable the warning light. Not sure about other models. But All you want is to ignore the warning light, then the black tape would work. For my PP, the TPMS warning light is way to the right side of the dash display and was no bother, so I just left the warning on all winter long when I did not have the TPMS sensors in my winter set of tires.

 

Just curious but did you try using the TPMS reset button underneath the steering wheel? Its right beside the obd2 port.

 

What that pushbutton does is set the low-pressure warning threshold that you want.

You use it by first inflating the tires to the pressure you want, then turning the car to IG ON, holding the button until the TPMS light blinks 3 times, leaving the car ON for a few more minutes, then turning it back off. This is in the owners' manual under "How to initialize the tire pressure warning system."

The car will receive the current pressure from all four wheels and take those to be the normal pressures that you want, and set the warning thresholds to a certain proportion below each one.

Me, I think the warning thresholds are way too low when set with the normal tire pressure, so what I did was overinflate the tires, then use the button, then deflate the tires to my preferred pressure again. That way, I get the warning only a couple psi below my preferred pressure.

The only time I have to push the button again is if somebody else has been working on the car and they pressed it because they thought it does something else. Then I have to overinflate the tires again, set the threshold back where I had it, and return them to my preferred pressure again.

Happily, the Discount Tire guys did not press it for me, so the warning thresholds were still where I want them. (They are shown in the Techstream data list.)

 

That's how it works in my 01 sienna van but for some reason I didn't think I had TPMS sensors in the wheels but i'm about to pull the tires off so i'm going to look again for some reason I don't think there is but of course the problem is not in my van it's in my 09 prius but i've bought a set of TPMS sensors that are supposed to work with the megahertz range of my 09 and people have used this brand before in this model car and had no problems even with the tire place using their computer to register the TPMS sensors somehow at least to work and put the light off and they did not use tec stream

 

I did the reset maybe 9 years back, think I was running a bit higher pressures at the time, so stumble on that tactic.

 

Thats pretty cool I had no idea it did that .I was always cycling through my scan gauge and looking at tire pressures once a week to see where i was at. lol