Faulty TPMS?

TPMS light has been on for 3 days now but when I check my rear tire's pressure, both are at 36 psi according to the display. The pressure is early morning before I drive off and my commute is not long enough for the tires to warm up dramatically. Light will turn off for a little , then turn back on. I'm gonna put some air in the tires but I find it kinda weird how 36psi is setting off the TPMS.

 

Set the tires to the correct pressure. Then hold the reset button under the drivers dash. Maybe sensor was not setup correctly initially.

 

^ I haven't needed to do this, but if that's the protocol, I support this message.
I set my summertime cold psi to 30 and won't get a light until winter rolls around.

 

Until my warranty ran out, my truck was at the dealership anytime I thought I sensed the potential of a future problem. Take your 2019 to the shop and let them do first tier debugging! Make them earn their money...

Also, you mentioned 36 PSI "according to the display." Are you going off the dash alone, or have you double-checked with a pressure gauge?

 

You mention the rear tire pressures are both 36 according to the display, what about the front tires?

 

my light has been on for years I was thinking of hiding it behind a piece of black electrical tape.

 

Fronts are at 37 PSI. Double checked with my tire pressure gauge and it matches what is displayed on the dash.

 

I will try this later today. Thank you

 

TPMS values are only wild ballpark figures.

ALL electronic sensors in any vehicle are ballpark values.

If you didn't pay $1000 for the sensor, and receive a printed, signed, and dated calibration sheet with it, then that sensor is intended to provide relative readings, not accuracy.

Vendors love to Wow the technically illiterate with Chinesium electronics, and Toyota is no different.

 

actually these sensor are suprisingly accurate when the system is functioning. however both the TPMS in your tires, and the sensor antenna (usually housed somewhere near the front and rear of the car in a small module (varies on models/makes)) can be faulty, or get water intrusion.. and go haywire, and new ones need to be coded to the CAN system.. sounds to me like yours is showing overpressure... I am at 28PSI cold, and as I drive it goes up to around 34PSI... I recommend you read the spec on the inside of your door which I believe is 28-32PSI.. then do a reset of the TPMS system.

reset proceedure:

1. Park the vehicle on level ground. ...
2. Check the pressure in all four tires to make sure they are inflated to the proper pressure. ...
3. Start the vehicle.
4. Locate the TPMS reset button to the left of the steering column. ...
5. Press the reset button and hold it until the TPMS warning light on the instrument panel blinks three times.

you may possibly have a sensor that the battery is failing on.. it will need to be replaced.. they are typically a 5-10 year/100k mile battery..

 

They're accurate at their calibration temp.

Cold tires, 95F ambient, mine read 3 psi higher than a trustworthy dial guage. At -2F, they read 4 psi low.

I program systems that read these things, and I've used a lot of different vendors' sensors. My truck's sensors are pretty accurate by comparison w/ most, but it's just ballpark accuracy.

The TSS sensor however is surprisingly accurate and stable over the limits I tried (0C - 40C), & +/-5cm at 50m really isn't bad at all. I only have the one to test though. I want another to put on a fixed wing drone. Terrain following...

 

Hmmmm . . . My manual says to turn the key to the on position, not start the truck. Maybe that's why I have never been able to get it to work.

G.

 

Go to the dealer. These sensors are wildly finicky, like MaTaco_4x4 says. Even too high PSI in the tires can throw them off. I had to have mine reprogrammed and reset multiple times. The last time it happened, there was a TPMS light warning because the SPARE (who puts TPMS in a spare?) was a little low on air (!). Of course, the system won't tell you that, so you need to drop the spare manually and check its air pressure.