2008 Jeep Wrangler Owner's Manual - Page 335

334 STARTING AND OPERATING inflation pressure of each tire on your vehicle, and inflate each tire to the vehicle's recommended cold placard pressure value. 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. The Tire Pressure Monitoring Telltale Light will flash on and off for 75 seconds, and will remain on solid when a system fault is detected. The system fault will also sound a chime. If the ignition key is cycled, this sequence will repeat, providing the system fault still exists. A system fault can occur by any of the following scenarios: 1. Jamming due to electronic devices or driving next to facilities emitting the same Radio Frequencies as the TPM sensors. 2. Installing some form of aftermarket window tinting that affects radio wave signals. 3. Lots of snow or ice around the wheels or wheel housings. 4. Using tire chains on the vehicle. 5. Using wheels/tires not equipped with TPM sensors. NOTE: If your vehicle is equipped with a matching full-size spare wheel and tire assembly, it has a tire pressure monitoring sensor, and can be monitored by the Tire Pressure Monitoring System (TPMS). In the event that the matching full-size spare tire is swapped with a low pressure road tire, the next ignition key cycle will still show the Tire Pressure Monitoring Telltale Light to be ON, and a chime to sound. Driving the vehicle for up to 10 minutes above 15 mph (25 km/h) will turn OFF the Tire Pressure Monitoring Telltale Light as long as none of the road tires are below the low pressure warning threshold.