Originally Posted by Nottalot
Electronics can be a huge pain in the ass, look through posts on here where the battery tests for a charge but the Jeep won't start. So even though the sensor batteries are testing good, they could still be the issue. You could try replacing the sensors, shouldn't be anywhere near $800, or you could get a programmer and disable/lower the threshold.
Thanks for everyone's input! The problem has been solved, and it indeed was the sensors.
I wanted to share the info I learned along the way in the hopes it will help others.
1) If there is a low pressure reading, inflating to the proper pressure and then driving a bit works. BUT, if there is a TPMS fault, where the light flashes for 75 seconds and then stays solid, there are NO tricks that have to do with inflating or deflating to certain pressures.
2) If the battery on the sensor is getting low, the TPMS tool will show the sensors as OK. BUT the sensor battery can be just low enough to not send a strong enough RF signal to the WCM.
The Jeep service department was able to isolate the two sensors that were going bad. I went to Advanced Auto to get the exact sensors that were on the other tires. Cost was about $55 each. I took the sensors to my mechanic who installed and programmed in new codes. Drove a bit and TPMS fault light went out.
Here's the last piece. All 4 tires were inflated to 40psi after the new sensors were installed and the drive to clear the fault. The computer used to test and enter the codes showed 40psi for 3 tires and 36psi for 1 tire. The spare on the back did not register since it was not in motion. This likely means that the battery on the sensor for the tire reading 36 is going bad. If the TPMS fault goes off again, I'll know it's that sensor that needs to be replaced.
I think there are several points to consider for the future or anyone having issues. 1) Most of the time the simplest solution is the right solution. I and many others involved spent countless hours trying to find the correct "trick" to fix the problem. 2) If you're replacing your tires due to low tread, like I was, replace the sensors at the same time. The sensors and the tread are likely to both last you about the same time 3-5 years. Easier to take care of both to save the headache when the sensors go bad soon after changing the tires.