TPMS/remote start issues

I own a 2009 jeep Sahara unlimited. I have been having some remote start issues. Once I hit the remote starter my vehicle honks twice and starts as it should. However, It shuts off about 45 seconds after it starts. There is a dreaded "hammer" symbol on the display. Has anyone else had this experience?

Issue number two is when I purchased the vehicle in August 2016 it came with 255/75 R18 on it . I recently replaced them with 275/60 R20's with 33" Dick Cepek Trail Country tires. Ever since then I have been getting a flashing then steady tire symbol on the display. I took it to Discount Tire and they informed me that Jeeps automatically re calibrate themselves, but one of the new tires had a bad TPMS. I told them they were ordered online with the tires and rims and should have been brand new. I only ordered the 4 tires to go on the ground and plan on ordering the spare in the near future. Could the tire monitoring system be picking up the different tire pressure of the spare tire?

 

Is it an upside down hammer? Also when I went with bigger tires I had problems with the tpms sensors. One had to be replaced and one had to be reprogrammed to the Jeep frequency. P.s. One sensor took 50/60 Miles Before it picked it up. And no the spare wheel sensor will not be picked up

Doug