Retail Service

Patriotic duty

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Patriotic duty

SUBJECT VEHICLE: 2007-08 Jeep Patriot.
SENSOR IN TIRE? Yes (sensors are mounted to each road wheel as part of the valve stem).

The 2007-08 Jeep Patriot’s tire pressure monitoring system (TPMS) uses radio and sensor technology to monitor air pressure levels. Sensors are mounted to each road wheel as part of the valve stem. They broadcast to a central receiver circuit inside the Wireless Control Module (WCM). Transponders are located in wheel housings that locate all of the sensors.

If a warning condition is present, the WCM will send a request to illuminate the low pressure warning light, sound a chime and display warning messages on the instrument cluster.

The TPMS remains active even if no tire pressure message is displayed.

Sensors lay dormant when the car is parked, then wake and begin transmitting when the vehicle reaches speeds of more than 15 mph.

Once the wheels stop rotating for 20 minutes, the sensors shut down until they are awakened again. While in park mode, the sensors still send messages once every 13 hours.

Sensor exchange

You’re now ready to install a new sensor. Sensors can be easily identified by a black sensor body with a white oval insignia on it. Make sure you retain the original valve stem core and cap for reinstallation. Do not substitute either item. Also, do not re-use the sensor-to-wheel grommet. Always use a new grommet when installing a sensor. Here’s how to exchange an old sensor for a new one:

1. Remove the tire and wheel assembly from the vehicle and let the air out of the tire.

2. Remove the sensor nut and remove the sensor from the wheel.

3. Wipe the area clean around the sensor/valve stem mounting hole in the wheel.

4. Insert the sensor through the wheel, keeping pressure against the rear of the metal valve stem.The potted side of the sensor must be positioned toward the wheel (Figure 1).

5. Using a thin-walled socket, install the sensor nut. While holding the sensor in place, tighten the nut to 58 in.-lbs.

6. Mount the tire on the wheel.

7. Once the wheel has been mounted to the changer, position the sensor valve stem 210 degrees from the head of the changer in a clockwise direction before rotating the wheel to mount the tire.

Position the wheel on the changer so the sensor valve is 210 degrees from the head of the changer in a clockwise direction from the mounting end of the tool. Rotate the tool in a counterclockwise direction to mount the tire.

8. Adjust air pressure to specification. Make sure the original valve stem cap has been installed.

At this point, you are ready to retrain the newly installed sensor.

Retraining procedure

Using a radio frequency signal, each sensor transmits tire pressure data once every minute. Each sensor’s broadcast is uniquely coded so that the WCM can monitor the state of each of the sensors on the four wheels.

The WCM automatically learns and stores the sensor’s ID while driving after a sensor has been replaced. There is no formal retraining procedure other than to drive the Jeep for at least 10 minutes while maintaining a continuous speed of more than 15 mph.

During this time, the TPMS will automatically learn the new sensor ID code and will clear any DTCs automatically. If the sensor cannot be retrained, consult the manufacturer.    ■

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