2008 Jeep Wrangler Owner's Manual - Page 332

STARTING AND OPERATING 331 The TPMS will warn the driver of a low tire pressure if the tire pressure falls below the low pressure warning threshold for any reason, including low temperature effects, or natural pressure loss through the tire. The TPMS will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off until the tire pressure is at or above recommended cold placard pressure. Once the Tire Pressure Monitoring Telltale Light has been illuminated, the tire pressure must be increased to the recommended cold placard pressure in order for the Tire Pressure Monitoring Telltale Light to be turned off. The system will automatically update and the Tire Pressure Monitoring Telltale Light will extinguish once the updated tire pressures have been received. The vehicle may need to be driven for up to 10 minutes above 15 mph (25 km/h) to receive this information. For example, your vehicle may have a recommended cold (parked for more than three hours) air pressure of 35 psi (241 kPa). If the ambient temperature is 68°F (20°C) and the measured tire pressure is 30 psi (207 kPa), a temperature drop to 20°F (-7°C) will decrease the tire pressure to approximately 26 psi (179 kPa). This tire pressure is sufficiently low enough to turn ON the Tire Pressure Monitoring Telltale Light. Driving the vehicle may cause the tire pressure to rise to approximately 30 psi (207 kPa), but the Tire Pressure Monitoring Telltale Light will still be ON. In this situation, the Tire Pressure Monitoring Telltale Light will turn OFF only after the tires have been inflated to the vehicle's recommended cold placard pressure value. 5