Attached to this article is the new version of the J1939 protocol. Please take note of the command/control changes:
The key for you to read higher pressures will be on page 7. In PGN 64953 you will see Byte1 is Tire location (axle#, tire#), Byte2 is the Reference Pressure (what the tire is supposed to be pressurized to under cold conditions, this is the basis for all alarms), Byte3 is current tire pressure (8 kPa/bit, allowing data from 0-2000kPa or 290PSI), Byte4 is when the last reception was received from the sensor (1 minute/bit), Byte 5 is broken down by bit (bit 8 = new air flag [1=new air], bit 7-1 = RF strength 0-100 [127=no data]), Bytes 6/7/8 are all the serial number of the sensor assigned to this location. This data is available every 40 seconds for every programmed sensor.