Tire Pressure Warning Light - Dead Sensor..

There are only 3 "systems" involved:

1. The tire pressure sensors in the tires -- total of 4.
2. The TPMS ECU which is behind the glovebox
3. The TPMS Reviver which is behind the side panels in the rear hatch area.

Well, and the wiring between #2 and #3

The codes in the ECU are explicit to where the problem is....

Like which sensor isn't working. Or if it can't talk to the receiver. (Which means it can't read the codes from the tires.) If it says all sensors are bad it's probably the receiver. The receiver sends a signal strength input to the TPMS ECU which tells the ECU that there isn't excessive interference..... when there is too much interference it obviously won't be able to read the sensors at that moment.

But if the ECU knows you are driving (by a speed signal) and the interference doesn't improve it throws and error about the receiver being the problem.

This same TPMS system is on all Toyota cars in the US. (US law requires it.) It's pretty simple and should be easy to fix! Especially because the Service manual gives extremely clear instructions on troubleshooting steps to follow.

It's certainly not a mystery.

 

There should have been more information with code C2124 than what they provided. According to TechStream, I had 2 DTCs with my TPMS ECU.

C2124 - CANNOT RECEIVE A DATA FROM THE TRANSMITTER ID4 (MAIN)
C2126 - TRANSMITTER ID NOT RECEIVED (MAIN)

I was able to clear C2126, but not the other one (it continued to stay logged). That told me that based upon the 4 TPMS IDs programmed currently, that ID4 was causing the problem. While this is somewhat helpful, it's not entirely all that helpful. Who knows which tire ID4 was in.

They can print this page, but again, not too helpful unless you know which tire has which ID # associated with it. I read that they try to program them based upon tire location, but once you rotate or get new tires, that's most likely gone out the window.

I would try to provide a screen capture of this, but it's on my netbook and not my regular laptop. I only plan to use the netbook for possibly travel and for the TechStream use. I know, what a waste of money, right? lol.

Based upon your DTC, it appears they tried to find that particular sensor and fix it. The ECU will continue to log this DTC until the problem with the sensor is corrected. It's also entirely possible your sensors happened to be part of a bad batch, or the batteries were and they're just slowly failing. I'd try to get the dealership to replace ALL of the sensors. The DTC should stay logged in the ECU even if the light is not on. There is a "current" and "history" "X box" that it would mark in TechStream to give them the current state of that DTC.

I would love to be able to do some data gathering from the car with TechStream (it should be able to do this) using my newly arrived Mongoose cable, but I'm not exactly willing to continue to pay for the software. Wonder if there's other monitoring software that I can use with it? IF anyone has suggestions or recommendations, shoot me a PM on it and I will see what I can do.

Hope some of this helps!

 

Given how most dealerships are, you probably won't convince them to replace them all unless you start to raise some noise up the chain there. My guess is, they still might not do it unless one of the DTCs make them think they may all be failing. I'd be interested in the logged DTCs and the readings that each sensor is giving. They can provide this information just between a couple different screens (I don't recall all of them, only had about an hour or so to fiddle within TechStream so far). What would have been nice, is to know the IDs that were in the ECU before they changed one of the sensors, and then which ones are in there now. That way, you would know for sure if it was the new sensor or an old one that may be causing problems. I'm leaning towards the sensors based on the information (and also lack thereof) that we have so far.

Considering how many times you've been there with issues relating to the TPMS, they may also give in and do all the sensors in order to eliminate those as a potential problem in the event it continues. Those are something they more than likely have in stock and can do quicker than anything else.

You may want to call and talk to the service manager before you go in with the car. That way, you should be able to find out when he works and time your trip accordingly. Calmly explain the situation, that you've been in multiple times now for the same issue with no acceptable resolution. You may get further with a heads-up in an adult manner with them. I find that typically being cool-headed makes things better for all involved.

This is what makes me wish that they offered a free version of TechStream (read-only could be an option) and that you could carry a laptop in the car so that you'd have everything you needed when the light came on to pull information yourself. How nice it would be with an open-source version or some way to read all the different ECUs without paying the Toyota fee. Heck, I'd be willing to pay $50 for a 6 month subscription if they offered just a data gathering/logging version as long as it allowed access to all modules. The consumer could be much more prepared with information to take into the dealerships then.

 

I'm resurrecting this thread because today my TPMS light was on my entire commute. Not flashing. I checked my tire pressures when I got to work and everything's good (42/40). What should I do about the TPMS, is there something wrong? Please advise.

 

Did you try resetting it? Maybe it hiccuped and lost the set pressures.

Next time you turn the car on, keep an eye on it and see if it flashes for 60 seconds before staying on solid. If it does, take it into Toyota (you should be under warranty still) and let them fix it. Without a cable and TIS, there's no way to know what the ECU is seeing.

 

Ok this is weird - I checked the pressures again. The RF is 25! The other 3 tires are around 36.

The weather is cold again. I now suspect something's wrong with the RF tire (though it doesn't feel or look flat), but should the cold weather bring the others down from ~40+ psi to 36 psi?

 

Yes I think so if the temperature drop is enough; 1 pound per 10 degrees F is the rule of thumb.

Did you use the same gauge to check it each time?

Regardless, I would have that RF checked.

 

If your TPMS blinks for a minute, there is another way, he he, if you are bold. To see what DTC the TPMS is storing, ground terminal TC of the DLC3, then record the two-digit code that the tire light flashes.

See page CH-76 of:

http://www-rohan.sdsu.edu/~nash/TCH/TPMS.pdf

You don't have a TPMS problem, though, so, I'd say you should just set your tire pressures, then reset your TPMS "set" point, per the Owner Manual. Seems you might have a slow leak.