TPMS Sensors

I accidentally bought extra TPMS sensors for my Toyota 4runner. I have a used set of snow tires on wheels, and when I saw the rubber valve stems I assumed they had no sensors. I've never seen TPMS sensors with rubber stems before... Oops.

So I have these Denso 550-0103 sensors. Will they work for my 2018 Prime? They only list compatibility with older Toyotas up to 2016. But Denso doesn't show anything for the 2018 Prius, and all the parts stores only show generic sensors as compatible. If a generic sensor works, wouldn't an older Toyota specific one? Or have they changed the protocol or something? That wouldn't make sense, because tire shops probably aren't getting all new sensors every time a new car comes out. They are all the same frequency (315MHz).

 

I read that some of the Denso sensors are actually made by Pacific, but I'm not sure if that's true. The Denso sensors I bought are made in Japan, but both Pacific and Denso seem to be based in Japan, so that doesn't indicate much.

I also ordered a TPMS tool and some Autel MX clonable sensors, which haven't arrived yet. The original plan was to clone the Prius sensors so I could swap without reprogramming. But if I have the tool anyway, the Denso sensors are probably higher quality, and I can return the Autel sensors. The original sensors from Toyota (probably Denso) lasted over 10 years in my 4runner. At least one seems to have failed, but the rest are still working at 13 years old.

Autel is a sketchy company, or at least their US distribution is. A few reputable sellers sell their sensors (autozone, tire rack), but while looking for a TPMS tool I found at least 8 "competing" sellers on eBay that all happened to be based in the same town in New Jersey. I ended up buying the tool and sensors on Amazon, but that's not any better than eBay these days. I don't care about the quality of the tool as long as it works 2x a year when I need it. But the sensors will be in the tires for a while, and I don't want to replace them.

 

I bought an Autel TS501. Looks pretty similar to the TS508, but maybe older. It sounds like you got a good deal on the kit with sensors, that's about $365 now.

I have two Toyotas and my girlfriend has a Subaru, so I should be able to use it for all those cars.

 

I just looked at my Denso sensors, and they are in fact made by Pacific.

 

I brought the Denso sensors to the tire store, and they weren't able to get their tool to read them. I tried at home with my Autel tool, and it won't read them if it's set for 2018 Prius Prime, but it will if it's set for 2007 4Runner (which is what these sensors were intended for). But then presumably it won't be able to program them into the car, and I don't see a way to manually tell it the IDs to program.

Now that they are active and I have the ID numbers, I wonder if I can use Carista to program the IDs into the car? Or are they really just incompatible?

Update: Carista didn't work. It doesn't have the TPMS menu for me. I wonder if a Techstream tool would work?

 

I told the Autel the car was a 2017-2019 4runner. It was able to read the sensors, read the IDs in the car's ECU, and write the new sensor IDs into the car's ECU. But the TPMS light immediately started flashing and went solid for a few seconds, so apparently the car couldn't communicate with these sensors.

I guess I'll take them out and try the Autel MX sensors. I'm not sure if I should have the tire shop do that (and risk them having issues because of not having the Autel tool), or do it myself. Taking all the tires off and breaking the beads sounds like a lot of work.

 

I knew that in theory, but these are the right supplier, the right frequency, and designed for the same brand. Apparently Toyota has changed the protocol over the years.

 

I set up the Autel sensors. The car seems to be able to read them, but it's hard to tell for sure since they aren't in tires and the pressure is 0. I'm debating if I should take them back to the tire shop to install (which they would charge me $60 for), or just break the beads myself and install them. $60 is fine I guess, but I'm worried about the shop complaining they can't read the sensors, or that they don't have the tool to tighten the little torx screws on them, or that that will accidentally throw away the hardware from the Denso sensors making it so I can't return them.

 

The Autel is 23.5g, and the Denso is 35.5g. that's 12g or 0.42oz different, maybe enough to need balancing, or I could just add a weight next to the valve stem. The Densos have a much larger battery (one of the reasons I wanted to use them in the first place).

 

Well, I wasn't able to break a tire bead myself, so I guess I'll have the shop do it. I have a floor jack, a ratchet strap, a mallet, and some 2x4s, but the tire didn't want to cooperate.

I did learn that the sidewalls are super soft on the X-Ice "Snow". With no air they feel almost as soft and flexible as a mountain bike tire. I guess I haven't felt a lot of other tires in this size for comparison, but I'm pretty sure they are usually stiffer. I'm not sure why they made them that way, but maybe it's for noise or efficiency reasons? Obviously they need to make trade-offs with snow tires, and maybe handling is the best place to compromise because no one expects good handling from a snow tire.

 

I found a way to test the sensors. I don't have any kind of pressure vessel, but I put them in an empty garden sprayer and pumped it up. That got to 25 PSI. Not enough for the light to go off in the car, but enough to get a good reading with the Tire Assistant app. So I have a little more confidence that they will work.

 

Since I have a programming tool now, I used unique IDs for the new sensors. While I had no sensors, the car would always pick up the signal from the summer wheels in the garage. I don't want conflicting signals. And I want to let the sensors in the summer wheels go to sleep while not in use, if they have the ability.