TPMS question

We got a 2018 4runner from Carvana. I put my old FN FX pro wheels on it which had my totalled 2016 tpms in them. Discount tire flashed the tpms and the light came off. A day later it returned. Carvana ended up paying Discount tire for new TPMS and they were installed. Flashed and the light stayed on but turned off a day later after some driving. Now the light will blink and come back on every few days my wife says. I will sometimes go out in the driveway and start her car and the light will blink, stay on and turn off 2-3 mins after while in idle. All air pressure is good at around 33 psi. Is this just the TPMS learning?

 

No. What is the outside temp when she gets into the car in the morning? How old are the TPMS units in the wheels you put on?

 

The tpms on the wheels we put on were from a 2016. We moved to a 2018. This is a strange time here in the south where it can be very cold in the mornings but pretty warn in the afternoon. But she says once it comes back on it stays for a couple days. So it will turn on in the am when it's old and the pressure is probably reading low but when she leaves work in the afternoon it's nice and warm and her pressure should be reading where it would normally be but the light will still be one. I can see one day it is on and the next day I can go out to her can and turn it on and the light will blink, stay on, then go away after 5 mins of idle. And these are with new TPMS. At least with the old ones, they came one and stayed on. These come on and off.

 

It should turn off once it has reached the minimum pressures in all 4 wheels. Warm afternoons may only move it a lb or two, but a drive home of more than 10-15 mins should suffice. If they are sensors from 2016, the batteries may be done in one or more. I would have hoped DT would have scanned them to ensure they were working, but maybe not.

Manually check all 4 tires with a gauge. If they come back above 31 in the morning, it may be a sensor or two are done. SInce they are 6-7 years old, replace them all. Again, most batteries are only good for give or take 5 years on average.

 

The sensor in there now are brand new and were installed by discount tire. The old ones from the 2016 were working perfectly until the car was totaled and put on the 2018 30 days later. So either the 2018 can't read 2016 sensors or they weren't recalibrated correctly. Either way they were all replaced with new and those were calibrate to the 2018 but the light still returns every so often during the 2 weeks we've had them.

 

Gotcha. I'd manually check them in the morning, cold, then after a decent drive. Check all 4. I prefer a non digital gauge, but that's just me. If everything is good, take it back to DT and le tthem sort it out. Its POSSIBLE. they used one or more adjustable mhz units. You can tune them to 314.9, 315 or 433mhz. They are more expensive and I am not sure I've ever seen a DT use them, but weirder things have happened. Toyota has not used 315mhz since like 2008'ish. Your rig uses 433mhz.

https://www.autozone.com/engine-management/tire-pressure-monitoring-sensor/toyota/4runner/2008

 

You didn't mention which 4runner you have but some came with TPMS sensors in the spare tire. I believe the limited has them. just for shits and giggles, check your spare tire.

 

If that light is flashing for a minute and then stays solid, it means the signal has been lost. There's a note in the owners manual about "if you place a metal table" or something like that in the back compartment behind the second row, it can block the spare tire from sending the signal, which will cause this issue.

Ask me how I learned..........

 

Which is interesting, for AFAIK, only the Limited came with a spare with TPMS...