I had a similiar experience with my 2008 Tundra at Discount Tire when replacing the TPMS sensors. I was told by Discount, after they researched it since it still blinked, was that I need OAE sensors that are programmed by Toyota for my year Tundra. The cost of this through Toyota was $600-700. Not worth it to me, just check my tire pressure often and try to ignore the stupid light. Upon further research, since the light coming on randomly was concerning that it may be for real, I found a tire pressure system on camping trailer websites. These are commonly installed on trailers to monitor your tires. I bought a system made by Guta for $300 with eight sensors, four for the truck and four for the trailer. A four sensor system is about $250. Went on a recent trip and just LOVE this system, eight times the information at less than half the price. A display screen shows you the pressure and temperature of each tire and gives an audible alarm if there is a probem with temp or pressure readings. Sensors screw on the valve stem and you link them with the monitor. Definately the way to go.I have not been on this forum for a really long time, but I would like to share my experiences with respect to the TPMS Lost Communication error and hopefully save someone a boatload of wasted time on this matter. I have had this problem for over 5 years, and during some brief periods, it occupied large amounts of my time.
My issue was that when I first discovered the joys of downloading Toyota TIS Techstream, I was able to get a much better look as to what many issues that creep up from time to time. One of them was the TPMS Lost Communication. I first found out about it when I went to a Discount Tire store and they could not get the TPMS to work properly and recommended new TPMS sensors for each wheel. They replaced all of the sensors and it still did not work. They were kind enough to actually let me keep the new sensors and refunded my money since it didn't fix the problem and the old ones were working just fine apparently.
Then, I started looking down the other branches of the TPMS diagnosis tree. You see many posts about the TPMS being stuck in a loop and initializing the IDs for each sensor, blah blah blah. It may be the spare tire, etc. I even bought a Bartec Loop reset and nothing changed. I even did the other recommendations, like shorting out the two connectors on the OBDII, something like TC and CG (#'s 4 and 13) and nothing.
I tried everything humanly possible and was so frustrated that I thought about the most popular posts response to this problem, which is to disable the light. I thought this was a rather odd approach as it dominates the posts on the web, yet does not address the "why" we have these TPMS issues in the first place. I fixed my issue today and there was only one place in the internet where the even made a mention of "how and what" the real problem is so I will try and do a step by step breakdown of how to fix this and save you a lot of time.
My issues was the TPMS light would blink then stay on. It actually got to the point that the actual reset button, under the steering wheel and to the right, would not work. Normally, you would turn the vehicle to the "on" position I believe, then hold the button down until it blinks three times and then goes off. Well, I could press the button and hold it down for years and it did not work. It just kept blinking. When you turn the vehicle on, it would blink for a minute then stay on.
When I plugged in the Toyota Techstream, it gave some weird or nonsense readings on all of my sensors. My tires were reading something like -.23 psi and -58 deg temp. It pulled up the c2126 error for the TPMS "Lost Communication". The answer ended up being pretty much exactly what that code says.....lost communication.
If you have or see these weird numbers on Techstream and tried the ending or resetting the "loop", then just go and buy a new TPMS receiver/antenna. For my truck , the part number is 89760-0C010. It can be found on almost any Tundra from 2007 to 2014. The receiver/antenna is located just under the headliner all the way in the back of the cab. Just pull back the edge of the headliner and it is a couple of inches in from that edge and a little towards the drivers side from the middle of the rear window. You can get to it without taking down the whole headliner, just peel it back and gently pull down on it so you can hear a couple of the clips pop out and give you some room. It one 10mm bolt and its out. It literally will take less than 2 minutes to get it out.
The trick is finding the part. The retail on it is almost $400, and some of the salvage yards that know this sell the used ones for around $200. Ironically, the used price on these parts are more expensive that getting a BMW or Porsche sensor. The trick is to either go to a U Pull or a regular salvage yard and have the part already out. Leave the wire hanging outside of the bedliner and even show them where the parts is located. It just looks like a small, useless sensor and it is so easy to get to, they will give you a much better deal.
My area doesn't have many Tundras for salvage (they run so strong or they are shipped to South America and rebuilt for resale), but I ended up only paying $20 for the part. If it looks like the headliner has not been pulled out or down, there is a great chance that the receiver/antenna will be there. I also went down with my laptop, with Techstream on it, so I could just plug in the replacement and see if it works. It instantly picked up two sensors and the remaining two tire sensors showed up in less than 5 minutes. The great thing was the TPMS light went off and there was nothing else to do on it at all. No reprogramming...nada.
I watched those videos of people bypassing the TMPS light and it actually seems like a lot of hard and requires some skill...soldering, wire splicing, etc.....all to disable a light. I think the "black tape" option is the best deal if you are not trying to solve the actual problem. But now you know the why you are getting this error, if the other tips don't work out. I am not an electrical engineer, but I did examine both receivers. The old one seems to have had a few pins on the circuit board fall out or disappear. The boards have some chemical/glued on protection over the circuit boards, but it was eroded and gone in some of the sections where the pins are missing.
I hope that this helps. I had spent hours at a time working on this, on and off, for so long. Some of it just getting the techstream and others shorting out connectors, etc.... but the communication was just truly lost. Just like a doctor, start with the simple stuff first.
Have a tire place check to see if the sensors are transmitting properly. With a handheld scanner, they should transmit the tire pressure and ID number for each one. Have them check for a sensor on the spare tire, too. Most, and possibly all of the Tundras from 07 up do not have one, but you never know. Sometimes the one sensor that is not working is the spare and people get stumped because the other 4 are just fine and no one checks the spare. If one sensor is not transmitting properly, or not working at all, then replace the defective sensor that is not transmitting. Don't let them sell you the replacement of all of them.
Ask to see if they can give you any DTC codes and a printout that contains all of the ID's for your TPMS sensors. I took a picture with my phone of the results once off of these handheld devices. You may need this later if you want to try and register the sensors again in Toyota Techstream. If it pulls C2126, find a way to get Techstream access (you can download and it runs best on XP and Windows 7) or see if they let you look at the screen. If all 4 tire pressure readings are whack-a-doodle and the only code is C2126, then start trying to find that receiver in a salvage yard and it should take care of it.
I hope that this helps. Please double check some of the info, like which posts to short on the OBDII connectors for the reset, and the part numbers and other possible models that you can use for the receiver/antenna. I'm not sure exactly how the saying goes, but they say that people are smart who learn from their mistakes. People are even smarter when the learn from other people's mistakes. I hope this helps out.
I was just about to wrap this up and I found the link to "Gearmo"...all props to him in solving this riddle. He actually purchased the TPMS ECU and the antenna and discovered the solution. The link is below.
Good luck and I hope that just one person reads this and it all works out for them.