TPMS question - light comes on after driving, goes off after

Are you still covered under your warranty? If the TPMS sensors are a little over 3yr, you sound like you are a little under your 3 yr, 36K period. I'd take it into the dealer to get documentation and have them replace the bad one(s), perhaps the set. They can use their computer to see which sensor(s) are not reporting properly.

 

Read the owners manual as far as pressing the reset button. I don't know if its possible the prior owner liked to jack up his tire pressure and then hit the reset. My 2006 Gen2 I think the alarm is hard set at about 26.5 psig, but I hear later model years owners talking about hitting the reset button to adjust the alarm pressure based on current tire pressures.

After that, failure modes are possible for a sensor. Unfort Toyota does not read out the tire pressures for us on a screen so you'd have to use a device eg Techstream with miniVCI to see the sensor outputs and see what is going on.

 

The 2010-2011 model has the reset tire pressure button, the newer model such as the 2012-2014 doesn't have it...

As for investing in a Techstream miniVCI, I agree with this since it cost around 100-110$ just for a diagnoses on your vehicle. So its better to buy the device since its around 60-70$ on ebay. All you need is a working window 7 laptop.

 

+1. It isn't hard to find that for <$25 now. Once you get it working, the software will tell you the current pressure and temperature of each sensor as well as its set point. By bumping the pressures up or down you can figure out which sensor ID is on which wheel.

These sensors sometimes can be flaky, particularly as they get older. Sometimes they just fail (wjtracy's experience) and other times they become intermittent (my current situation). However, if these still are under warranty, I would get it into a dealer and let them figure it out.

 

My 2012 has the TPMS reset button.

Sounds like a failing sensor. Fail when warm. Dealer service will have to use a heat gun to find it.

 

Heat Gun = Interesting idea....other approach is to change pressure and watch (via Techstream) which tire moves...takes a couple minutes for a pressure change to register.

 

It's maybe preset to the door jamb pressure??

 

Techstream will show a DTC naming the sensor if the ECU loses communication with it (it is held if communication restored). Then just bump the pressures manually one at a time to figure out what tire matches that ID.

 

Have you checked if it's out of warranty? I'd assume yes, but just to ask.

Personally, I would just do nothing, check tire pressures more frequently. The system seems to be a cash cow. But I also know how easy it is to get drawn into making it right, fixing it. But this is one case I'd just hang in there, ignore it.

 

I can only think of one reason for the "dropout" of the sensor readings, and that's interference. It's -possible- one of the coils in the ignition system is causing the interference. I'm pointing there because you said it's the fronts. It could also be a bad or noisy headlamp "ballast" if you have the LED or HID lamps. Especially if you have aftermarket ones.

Anyway, someplace else to look.

 

I am not sure if you are orig owner, but the most likely explanation seems to me 2 bad sensors. You can try my trick (search TPMS Management with Techstream) I got a spare Gen2 TPMS and put it in a binder clip...now it reads 49 psig and I am using the bogus reading from under the front seat to silence my TPMS light. I used Techstream to enter the new code of the "bogus" TPMS. Not sure if the trick works with all Denso TPMS...but even without the binder clip you should read zero psig and 80 deg F whatever tire temp.

 

Toyota should probably fix it for you (not sure the certified agreement), but the implication is the prior owner maybe did some rotations with winter tires or something and maybe swapped out the TPMS. I am going on over 10-years old for 3 out of 4 TPMS (one died at 9.5 years).

PS- the other thing you can do on Techstream is re-enter your existing codes in reverse order. This would re-assign the codes and you could see that the registers work when given a valid TPMS signal.

 

Or rotate your tires, front to back. I believe there is only one antenna and it is in the rear of the vehicle. If the MIA sensors show up then, they may have weak batteries (and thus need replacement anyway).

 

Of course the easier suggestion (already made) is to see if it is covered on your CPO warranty and just have the dealer fix it! That is generally one year coverage for manufacturing/QC issues. This is not a wear item. I'd ask to have all 4 done since 2 already have failed.

 

I think you lost the TPMS lottery. Statistically, someone will have their sensors fail prematurely. If it were me, I'd have Americas Tires see if they can recondition it to work. They are my go to tire installers. Failing that I'd put a sticker over the light and check tire pressure regularly like I do on every other vehicle I own.