TPMS light was flashing but now is on continuously. I had a small leak in one tire and thought this was the issue but now, even when I have the tires all at 38 psi, the light remains on. I'm assuming this means one or more sensors has given up the ghost. I'm assuming the light won't go on due to a higher than expected pressure. Does this situation require Tech Stream or are there ordinary OBD scanners that could answer the question?
just buy a new set of 4 from amazon. It'll cost less than $42 ROADFAR 315MHz Programmed Tire Pressure Monitoring System Sensor TPMS Sensor Fits For Lexus For Scion For Toyota 4pcs 4260706011 4260733011
This is by far the most common reason for what you see, but not the only reason. I have experienced infrequent intermittent warnings when the TPMS system failed to read a sensor for 5 to 20 minutes at a time (that is warning light time, which is shorter than actual missing sensor time), then suddenly catch and put the light out. This could happen a half dozen times on a single long day crossing the state, then disappear for more than year. With an old ScanGauge-II updated show individual tire pressures, I was able to figure out which sensor, and distinguish this mode from an actual low pressure warning. It happened on both summer and winter wheel sets within a week, straddling a seasonal tire/wheel swap, so wasn't just a single sensor. But it hasn't repeated since getting new sensors all around with the most recent tire replacements. A few other people - not many - have suffered failure of the receiving antenna module. This list probably isn't complete.
When the TPMS flashes and then goes continuous it means a sensor is not being received. If it just comes on continuously it means low pressure. 99% it is a sensor with a bad battery. Change all four. They each have a unique id which has to be written into the system when replaced. They normally have their battery go dead in 8-10 years so you are due. Techstream or a few dedicated tpms scanners can write the new ids. ID2 is bad in this case. ID5 is optional for the spare but the system here is set for “Main Tire” sensors = 4.
