2009 Chrysler PT Cruiser Owner Manual - Page 266

264 STARTING AND OPERATING TIRE PRESSURE MONITORING SYSTEM (TPMS) • The TPMS will warn you of a low tire pressure based on the vehicle recommended cold placard pressure. • The tire pressure will vary with temperature by about 1 psi (7 kPa) for every 12°F (7°C). This means that when the outside temperature decreases, the tire pressure will decrease. Tire pressure should always be set based on cold inflation tire pressure. This is defined as the tire pressure after the vehicle has not been driven for at least three hours, or driven less than 1 mile (1.6 km) after a three-hour period. The cold tire inflation pressure must not exceed the maximum inflation pressure molded into the tire sidewall. Refer to the "Tires - General Information" in this section for information on how to properly inflate the vehicle's tires. The tire pressure will also increase as the vehicle is driven - this is normal and there should be no adjustment for this increased pressure. • TPMS will warn you of a low tire pressure if the tire pressure falls below the low-pressure warning limit for any reason, including low temperature effects and natural pressure loss through the tire. • TPMS will continue to warn you of low tire pressure as long as the condition exists, and will not turn off until the tire pressure is at or above the recommended cold placard pressure. Once the low tire pressure warning has been illuminated, you must increase the tire pressure to the recommended cold placard pressure in order for the Tire Pressure Monitoring Telltale Light to turn off. The system will automatically update and the TPMS Telltale Light will turn off once the system receives the updated tire pressures. The vehicle may need to be driven for up to 20 minutes above 15 mph (25 km/h) in order for the TPMS to receive this information.