Not sure about Gen1 but the Gen2 shows the TMPS by location (FR,FL,RR,RL) So you need to relearn them after each rotation. This can be done without the tool. Use the same process as below. 1) Make sure your tires are inflated to the recommended psi. 2) Turn ignition to the on position. If you have a push button start, push the start button without pressing the brake pedal. 3) Push the hazard light button 6 times. The horn should honk and you should see "Train left front tire" in the LCD display between the tach and speedo. 4) Release air pressure in the front left tire until you hear the horn honk. The LCD display should now read "Train right front tire". 5) Release air pressure in the right front tire until you hear the horn honk. 6) Repeat for the right rear tire, and then the left rear tire. 7) You should now see "Training Complete" in the LCD display. 8) Fill your tires back up to the recommended pressure I stole this from here: How To Train TPMS with no learning tool If you use the tool it just means that you don't have to deflate and re-inflate the tires.