This is more to pass on what I learned. 2010 Jeep Commander, 3.7L/5spd W5A580 trans 4X4. I have the base TPMS system, just the light, NOT individual pressure readouts of each tire in the EVIC.
I had the TPMS light go off just as we got cold snap locally, but NOT below freezing. I usually keep up with my tire pressure so I was bit surprised. Check air pressure, it was good, even added a little to make sure I was well over the min pressure to set off the light, the light would NOT go out, even after driving a couple of miles. (driving a couple of miles is sometimes needed for TPMS changes to register).
If I did NOT have my AutoEnginuity tool, I'd probably be stuck with just going to the dealer or local tire shop and just having them diagnose and replace it. I'm sure that bill would be approaching $200 or more. There are other tools some of you might have that can read TPMS codes and tire pressures as well.
First, the TPMS is part of the Wireless Control Module that also does the RFID/Transponder Key and remotes. Once I learned that I could scan the right module to "easily" find the code, it was the #4 Tire Sensor Fault. But which one is the #4 sensor?, I rotate the tires as well.
The FSM states to isolate the bad sensor, deflate a tire to 20 PSI and check the pressure readout of all 4 sensors, thus identify the change in each sensor. My AutoEnginuity scan tool has monitoring readouts, I was able to monitor the reported tire pressure for all 4 tires, but it doesn't identify which number sensor goes with which tire.
My first guess was wrong as too what might be #4. And sure enough, by process of elimination, I identified #4 since it read 37 PSI regardless of what pressure was in the tire, nor how it changed.
It "appears" the base TPMS system assigns the Driver's Side Front Tire Sensor #1 and counts them going clockwise (looking from above) for the Driver's Side Rear Tire Sensor to be #4. Or it could just be a coincidence my tires were assigned those numbers and the tires stay the same number in the TPMS system and they change as you rotate them.
If you have the Premium TPMS system, other than reading the actual diagnostic code, you probably can do all this troubleshooting yourself with the EVIC readout. If one tire reads the same pressure, with no changes, despite deflating that tire to 20 PSI, pretty good indicator that is a bad sensor and its in that position.
RockAuto has a Denso Senor specifically programmed to my Vehicle, i.e. it should work right out of the box, for $40, it appears much higher quality then the cheaper sensors they offer, I won't touch the AirTex Brand they offer for cheaper, the only thing AirTex I have purchased failed within 1/5th the expected life if NOT sooner. I have access to tire mount and balance machine and will try to change out the sensor myself.
Some TPMS systems require programming to replace sensors. Some do NOT and automatically register the new sensor after driving a few miles. My Commander and most Chrysler vehicles TPMS systems do NOT need programming if you use the sensors designed for it.
And just about all aftermarket sensors require programming, they're designed to fit multiple vehicles and must be programmed to the exact parameter of the particular vehicle they are being installed. BUT, you can purchase aftermarket sensors "Pre-Programmed" for your specific vehicle thus they will work out of the box without programming from a special tool. No my autoenginuity tool can NOT program TPMS sensors, at least NOT aftermarket replacement TPMS systems.