For all GM vehicles equipped with Tire Pressure Monitoring (TPM) system, a "Sensor Re-Learn Procedure" must be performed after tire rotations, Remote Control Door Lock Receiver Module replacement or Tire Pressure Sensor replacement. Ensure that the vehicle is in the TPMS Learn Mode, and follow the service procedure. Hold tool against the sidewall of the tire, near the valve stem. Depress Learn button while holding the tool against the tire sidewall. Note: The tool back can be touched on side wall of the tire, and antenna shall be pointed to valve stem almost perpendicularly. Depress Learn button firmly, rather than depress once and then release button. The green LED indicates that the tool is transmitting. The reset order is Front Left - Front Right -Back Right -Back Left.