greeknasty

Still have stock tires on havent changed anything, i put faith in my TPMS sensors but for the hell of it checked the psi today and all of them are 26 psi. what the heck?? I know tpms isnt an excuse to not check psi but all my other vehicles give me warnings at under 30psi so this was kind of a "woah" moment
Is there any way to check and see if the actual sensors are working?
the manual states Your vehicle has also been equipped with a TPMS (tire pressure warning system) malfunction indicator to indicate when the system is not operating properly
i havent had any warnings so im not sure whats going on

vlad_a

Deflate one tire to 24 and see if it will trigger the orange TPMS light. I was running on 24PSI in OBX and it sure did engage TPMS. You might have been right on the threshold.

Droid13

TPMS is only required to proactively alert when pressure is 25% or more low, 26psi is close, but might not have reached the alert set point. I believe the alert point is calculated when the reset switch is used. If the tires were at 32psi at the last reset, it doesn't need to trigger until 24psi. If the reset occurred with the tires at 35psi, then the lower alert point should be a little over 26psi.

kitlz

vlad is right. Deflate the tire and check if the TPMS light comes on. And it depends on the psi when TPMS was reset like Andy said. The light generally comes when a tire drops about 6 from that point. Best thing to do is overinflate the tires slightly, reset TPMS, then adjust to what you want so you're warned sooner.

greeknasty

Thanks for replies I will try that!
just so I'm sure. Its in park press On then hold reset button 3 secs. Correct?

F250

If it's working, you don't need to deflate very much at all to see the change. I've had a small sheet metal screw near the edge of one of my rear tires for over a week, and the pressure has not dropped a single psi in that time frame. Tonight, thinking that the screw had not completely penetrated, I decided to pull it out to KNOW whether or not it was a liability. HOWEVER, before pulling the screw, I had a bottle of soapy water handy as well as a fresh tire plug kit so I could plug the hole immediately, if necessary.

Pulled the screw, and there was no hissing. Poured on some soapy water, and there was an ever so small but continual flow of tiny bubbles. I grabbed my already prepared plug tools and had the hole reamed and plugged within 30 seconds, but it only really lost pressure for about 10 seconds between the reaming and plugging steps.

Sooo?? I had checked the TPMS readouts before doing anything, and all four tires read an even 33 psi. Immediately after plugging the tire, I rechecked the TPMS and the one tire had lost only 1 psi, but that difference was captured by the TPMS system! I'm pleased with seeing the TPMS system be that responsive, but am NOT pleased about having to replace a tire which still has at least 1/3-1/2 of it's tread life. Regardless, the plug is only about 1/2 inch away from the tread corner, and since it's my wife's vehicle, the tire has to go!

vlad_a

Keep in mind, on 3RX only 450h version displays the actual tire pressure. RX350 only has the warning light.

jfelbab

If all tires were reading 26 psi, I'd suggest you might want to check your tire pressures more frequently, especially now as the seasons are changing.

Your tire pressure, whether filled with plain air or nitrogen, will change 1 psi for every 10 degrees F of temperature gain or loss. Tires should be set to the desired psi when cold with consideration given to the trending temperatures.