I just went through replacing two sensors on my 2008 LX570.
Here's what I found;
I purchased and installed two brand new Denso units (I got off of amazon). I recorded the ID numbers for each of these. I purchased a techstream and OBD2 cable off of ebay and installed the software. I read online that people have successfully used techstream but I call BS..... After
fighting my way through the install I could connect to my LX and view the TPMS ECU. I paid "extra" for a highly reviewed ebay seller and although he was very helpful in getting the software installed it was a total PITA. But after about two weeks of messing around I got it to work.
Here's the TPMS ECU info screen:
On there, I could see that two sensors were not responding and there was a TPMS ECU fault code (<- This part is important). There were actually two fault codes. These were C2121 and C2177. These are not the normal engine/chassis ECU codes and did not show up on my normal OBD2 scanner.
I tried to go through the Utility function to replace the two sensors but I would get a communication error every time. The ebay seller even sent me a second cable and some updated software. Nothing worked. This is a common problem and there's a bunch of threads about the error code. None of the suggested fixes worked for me.
After about giving up, I did a bit more research and read that some people had luck replacing the senors using the Carista app. I purchased a 7 day pro version for $10 and used my Wifi OBD2 dongle and was able to replace the two dead sensor numbers with the new sensors on the TPMS ECU list. It took three tries but they finally synced. I could see the two new sensors on the data list and that they were reading. I thought I was home-free...... Celebratory beer cracked open.....
Started up the LX and surprise, surprise...... I still had the yellow triangle code on the dash and the "Check Tire Pressure System" error message. I tried clearing the TPMS ECU code but it would not work. I did the TPMS reset button thing about 5 times... I drove the truck for 2 days.... Still had the error.... I could see the new sensors were added and reading but the code would not clear. I was about the give up and go to the dealer and pay $120/sensor.
I then had an idea..... I tried using the Techstream software to go in and clear the TPMS ECU codes.
THIS WORKED! I about did a dance around the garage. All sensors read, and no error messages.....
A true victory beer was had.....
So short version;
Make sure you get Toyota compatible sensors ($35/each). Dont ask me how I know some "generic" 315mz sensors dont work....
Use Carista to "load" them on to the TPMS ECU ($10/week or $40/year)
(If you don't have a wifi/bluetooth OBD2 dongle youll need to buy one ($20+/-)).
Use Toyota Techstream to clear the TPMS ECU codes ($37).
None of this is easy, but it's not that hard either. I went through a ton of head-banging. I fully understand the importance of proper tire pressure, but it does not have to be this difficult to self-maintain when there's an issue. I considered just going to the dealer but the thought of paying $120/sensor killed me out of principle alone.
