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Sears should be aware that these tire pressure monitor systems need to be reset when the sensors are serviced. You may need to take it to Ford for the reset, unless you can find a local repair shop that knows how to perform it. Below is a bulletin.
LOW TIRE INDICATOR ON - TPMS SYSTEM SENSOR WAKE UP
2003-2006 Expedition, Explorer
2006 Escape Hybrid, Escape, Freestar
2006 Mariner Hybrid, Mariner, Monterey
Vehicles built with the tire pressure monitoring system (TPMS) sensors may experience a concern where the TPMS indicator is on solid and the message center (if equipped) displays "Low Tire Pressure". This may be due to the actual tire pressure being low due to time or temperature changes (10°= 1 psi). Adjusting the tire pressure to specification should turn out the warning light once the sensors have been awakened.
If the vehicle has been stationary for more than 30 minutes, it will be necessary to wake up the sensors with the training tool to force them to transmit the latest air pressure information to the smart junction box (SJB), or responsible module. This can be done by either driving the vehicle for 2 minutes above 20 MPH (32 Km/h) or by using the training tool. The sensors do not continuously transmit when the vehicle is not moving.
NOTE ADJUSTING THE TIRE PRESSURE IS NOT A WARRANTABLE ITEM.
Inflate all tires to the correct air pressure.
Place the ignition in the RUN position.
Use special service tool 204-324 for valve-mounted TPMS sensors or 204-363 for wheel mounted sensors.
Place the magnet on each sensor for approx. 5 seconds or ping each sensor at least twice after adding air to ensure the module has the latest air pressure data.
If the TPMS indicator does not go off after filling the tires to the correct air pressure and pinging each sensor then refer to the appropriate Workshop Manual symptom chart.