Note that the below solution only works for '07 and newer models. 2005-06 tC have a more rudimentary TPMS system that only works based on wheel speed, while '07+ have TPMS sensors mounted to the valve stem.

Since I run two sets of wheels for daily and autocross, I don't really care about TPMS functionality, plus I frequently check my tire pressures anyway. So I figured out a way to disable the light.

During normal operation, the TPMS computer sends 12V to the gauge cluster. If there is a fault in the system, it won't send anything to the gauge cluster, and the cluster will illuminate the TPMS light. This is why simply disconnecting the TPMS computer still keeps the light on.
The solution is to always send 12V to the gauge cluster while the car is on, so the light won't illuminate. Luckily, the TPMS computer already recieves 12V on ignition, so we can just steal that from the connector. I found this solution on a Prius forum, looked through the wiring diagrams for both and found that they work identically. I wouldn't be surprised if this works on a tC2 or any other Toyota products of the era as well. I'm not responsible for messed up TPMS computers, gauge clusters or wiring though :)


^ Shown above is the TPMS computer, and the wires that need to be connected together.
The TPMS computer is located behind the glovebox and has one connector (T11).

^ Connector T11. Pins 5 (light green wire, to gauge cluster) and 7 (red wire, 12V ignition) need to be connected together with a jumper wire.


^ My solution: a jumper wire between pins 5 and 7 of the TPMS computer's connector

I disconnected the TPMS computer, installed the small jumper wire, and the light is gone. If you want working TPMS again, simply remove the jumper wire and plug in the TPMS computer again.

Hope this helps y'all.

 

huh… I just put a piece of black electrical tape over the light

 

So, just to be sure: After you install the jumper wire, you don't reconnect T11; you just leave it disconnected?

 

I just did this and the tpms light is now off completely. You leave the connector disconnected and tucked somewhere. You will need a very thin wire for the jumper wire.

Also, thanks @TofuDelivery86 for posting this!

 

It's pretty hard to get behind the glove box. Though, it was easy to take off the plastic plate that covers that area. However, I still don't know which connector is T11. Is it the grey one that's next to the white one in this photo?:


If it is, how do you get it off the fitting that it's attached to? (Both it and the white one are attached to a fitting that holds them onto the chassis.)

 

The connector is directly above glovebox, so you'll need to take the glovebox out which is also pretty easy to do. Once the glovebox is out, look up and you'll see the pink TPMS module along with the T11 connector.

 

Thanks H2K. Sounds like a pain but I'll try it :-)

 

Is there some trick to making taking out the glove box easy? It looks like you have to remove the dash to do it.
(Btw, when I open the glove box I can see up into what's above it; I can see the TPMS module.)

 

No tools needed really. You just have to unhook the damper on the right side. Then squeeze both sides of the glovebox inward so the upper part can clear and slide out. The bottom hinges are basically just clips which you can firmly pull the glovebox outward to detach.

 

I finally got around to doing it: H2k, you're a genius; it worked!
Turned out it was quite simple to remove the glovebox, using your directions, and, once I was able to resolve where everything was, it was easy to unplug T11 from the control module. I used #22 wire as a jumper; it worked perfectly.
I took a deep breath, resolved my trust in you, and started the engine: The light is off! Now trusting that something won't blow up somewhere down the line :-) Seriously, thanks, so much, for posting this hack.

 

Oops, I forgot to give TofuDelivery86 credit for coming up with the actual solution (but H2k was also very helpful). So, thanks TofuDelivery86!