Because, as you drive the tires warm up and that can warm up the sensor and thus the batteries so it starts to send a stronger signal. If the issue is not a weak battery, but it takes a few minutes for the car to figure out where each sensor is then it is likely that the tire dealer installed the wheels in different positions. Don’t worry about it unless they fail to display after a few minutes. Set the multifunction screen to watch something else unless the tire alarm (yellow light) comes on.

 

My sensors are original, so weak batteries must be the problem. I tried to get them replaced with my tires, but Sam's Club said they don't have tpms sensor's available for the 6th Gen lexus es350. They have sensors for 07-12 and 20-25, but none available for our 13-18 models

I did have them re-coded so the position of each tire is correct. But I have to turn off the car and back on and then my reading show up. I'll just deal with the delays for now.

 

On my ‘14 I purchased a second set of rims for seasonal (winter) use. The tire dealer installed a specific model of Autel sensors and cloned (programmed) them to have the same id numbers as the OEM sensors on the Lexus wheels. They worked perfectly…all I did was unbolt one set of wheels and bolt on the other set, adjust the pressures, and hit the reset per the Lexus manual (on the ‘14…the Gen 7 has a different procedure to do the reset). When I traded the ‘14 on my ‘20, part of the deal was for me to keep my winter rims. The Autel sensors were reprogrammed again to match what is on the car. They still work perfectly. Too many aftermarket sensors will only give you a “Go/Nogo” output rather than the actual pressure signal which the ES requires. Before this turns into (yet another) “debate” about aftermarket vs OEM I’ll just say to find a tire dealer who knows what they are doing and leave the discussion there. Good luck.