User21654321

I have a 2014 IS250 F Sport, and I am in need of some assistance. I am on stock wheels and I believe the original TPMS sensors. The TPMS light flashes on startup and stays on and as the title states, the pressures are not displaying.

Deep diving a bit, the car is receiving error code C2126 "Transmitter ID Not Received In Main Mode". Looking through the diagnostics, 2 of the 5 ID#s were reading N/A. The TPMS registry values were all present. There were multiple successful attempts to re-register them but the outcome did not change anything. The light still flashed and stayed solid.

Next, I took the car to Discount Tire and their tool indicated that all four tires were emitting signals and could read the pressures. At this time I did not realize the spare had a sensor and was not scanned. The tech plugged his tool into the ODB2 port and the light went off, I am not sure what he did. After 20-30 minutes of driving, the light flashed and stayed solid. Again, no readout on the dash.

I am not sure what to do next since the TPMS were transmitting the pressures. Should I take some time to map which tires belong to which ID#? That may help determine next steps. If both of the TPMS sensors that are reading N/A in the diagnostic tool are in the front or rear, it could be the transponder front or rear indicated in the link below?
https://parts.lexus.com/a/Lexus_2014...3-FD1F8437AF5E

I am open to any ideas and feedback.

Edit: Would one or two TPMS failing cause the dash to show no pressures?

cerbois

If they are original sensors in the tire the batteries could be dead (or on their way out). 10 years is a long time if you got that long.

cerbois

Kinda seem unlikely that the front and rear sensors you put in the link both went out at the same time???

User21654321

Even though all four are transmitting, verified by Discount Tire?

None of the sensors have been replaced. They are all original to the car.

cerbois

You make a valid point but I don t know the system well enough. That is a long time on sensors usually.
Maybe they are transmitting weak or maybe they are reading a stored (last) transmission??? I don t know for certain. Just giving a cheaper direction before changing those 2 sensors that would be strange to fail (front and rear) at the same time.
Might even be worth a try to disconnect car battery and let everything re set?

cerbois

did they work in the past and just stop?

User21654321

Unfortunately I did disconnect the battery for about a half hour. The TPMS flashed then was solid on startup.

They did work until a month or two ago. Do you know if one sensor failing causes all pressures to not display on the dash?

cerbois

One sensor should not cause them all not to display. But they will last about the same time and cold weather onset can finish their life OFF.
A tire place can also check each sensor with the tool.
I don t know what the next item would cause this failure .

cerbois

Looks like he re set the system and after it couldn't t read it after 20-30 mins it set the system light ON again.
I m out of other ideas, internet reading time or Lexus tech .

cerbois

bottom line is the car is not receiving the TPMS signal (or non is being sent), or the antenna system is not receiving the signal.
Someone would have to know that specific Lexus system to know where to check between the two.

swfla

iTrader: (1)

Go to a Japan car shop and have them use Techstream. This software will pinpoint the issue and eliminate guessing. There are many posts about going to Costco or national tire chains for affordable replacements. They stand behind the parts and labor. Don't risk new sensors from eBay as many are low quality and may not even work properly.

User21654321

I had a friend, not sure what software he had, but he was able to see the code C2126 "Transmitter ID Not Received In Main Mode" getting assigned. I would like to diagnose myself to limit the cost, but am having a difficult time determine the route cause.

athanato

with clone-able after market TPMS and the scan/programing tool you can clone your OEM IDs on to the new after market TPMS for a swap out...if there is enough battery power left on them for the scan tool to detect the signal.
When you program the sensors you have to turn the write protect option off in the tool, but its not named write protect - I can hunt the menu option for you down if you go that route, I had to do it on mine in order for it to work...just make sure you get the sensors that have the correct mhz freq for the car.