There is no relation between the TPMS light and these issues.... if the tires are all at pressure and the light is on (or more likely, flashes at some point then is on), there is a faulty TPMS sensor. To determine which is bad, you need to have a TPMS compatible scan tool to see which sensor number is ***** go to the sensor info and record all four sensor serial numbers and their "number" (1-4), then reprogram the sensors. When each sensor is recorded, notate the serial number and number 1-4 to the location of the tire on the vehicle. Then you can determine which sensor or sensors are bad based on either not taking a programming of course, or if they all program by matching the serial number/sensor number before to current location and replace the sensor(s). You will need to reprogram the sensors again after the fault ones are replaced.
The B1481 is indicating a resistance problem on one of the drivers squibs (air bag igniters). The only way to check this without replacing parts until it is fixed is to use a 2.5-3 ohm resistor to simulate a good bag. With the air bag removed, unplug one squib connector and install the resistor in the harness in its place and see if the fault clears... if it does not, remove it and reinstall the connector to the air bag and unplug the other squib connector and install the resistor on its harness and see if the fault clears. If it clears in either position, the air bag is faulty. You could also use two resistors for this test and eliminate the bag altogether if you wish, since obviously a failure on either requires replacement.
If the code does not clear in either position, then you will want to remove the column covers and unplug the clock spring. Perform the same test but with two resistors on pins 11&12 and on 13&14 (the two wire pairs for each squib) and again try to clear the code. If the code now clears and it would not clear with the air bag squibs replaced with resistors, then the clock spring is bad.
If the code still does not clear even with it bypassed with resistors prior to the clock spring, then you would have either a failure of the SRS ecu or the wiring in between it and the clock spring. No other possibilities here on a stock wired car (if someone had started hacking into wires for a radio install or something like that, of course all bets are off).
It is important to note that when these cars deploy bags, it is not unusual for the SRS ecu to burn out the driver with the large burst of current they send out, and as well it is even possible to melt the clock spring. On this particular year/model, the SRS ecu is most common to burn out though.