is not the first unique identification code received the processor 260 determines in step 322 if the received unique identification code is unique compared to those already stored for example if an operator incorrectly changes the tire pressure in a particular tire twice the second transmission of the unique identification code in the tire pressure change message will cause step 322 to determine that the received unique identification code is not unique as compared to those already stored if the received unique identification code is not unique compared to those already stored the relearn timer is decremented in step 336 and the loop 310 316 336 310 is reentered to wait for steps 312 and 314 to complete in the tire pressure detector 202 102 122 or 222 if processor 260 determines in step 322 that the received unique identification code is unique compared to those already stored the received unique identification code is stored in the next open memory slot in memory 270 step 326 then determines if the unique identification code just stored in step 324 was the last unique identification code expected for example step 326 may check to see if the last memory register has a unique identification code stored in it if the last unique identification code has been stored then step.