2005 Mercury Mountaineer Owner Guide 3rd Printing - Page 178

Tires, Wheels and Loading The tire pressure should be checked periodically (at least monthly) using an accurate tire gauge, refer to Inspecting and inflating your tires in this chapter. Understanding your Tire Pressure Monitoring System (TPMS) The Tire Pressure Monitoring System measures pressure in your four road tires and sends the tire pressure readings to your vehicle every minute while you are driving and once an hour when your vehicle is parked. The Low Tire Warning Lamp will turn ON if the tire pressure is 25% below the pressure listed on the Safety Compliance Certification Label (approximately 6 to 9 psi below the manufacturer's recommend tire pressure). If the tire pressure increases 2 psi above the "Light ON" threshold, then the TPMS light will turn OFF. Once the light is illuminated, your tires are under inflated and need to be inflated to the manufacturer's recommended tire pressure. Even if the light turns ON and a short time later turns OFF, your tire pressure still needs to be checked. In short, once the light has turned ON, at least one tire may be under inflated. When your temporary spare tire is installed When one of your road tires needs to be replaced with the temporary spare, the TPMS system will continue to identify an issue to remind you that the damaged road wheel/tire needs to be repaired and put back on your vehicle. During this time, the low tire warning light can periodically return or stay on, depending on the state of the damaged road wheel/tire. This will include the message center messages (if equipped). To restore the full functionality of the Tire Pressure Monitoring System, have the damaged road wheel/tire repaired and remounted on your vehicle. For additional information, refer to Changing tires with TPMS in this section. 178 2005 Mountaineer (mnt) Owners Guide (post-2002-fmt) USA (fus)