Compass 2WD L4-2.0L VIN 0 (2007)
Tire Pressure Sensor: Description and Operation
Operation
OPERATION
The battery operated tire pressure sensor is both a transmitter and a receiver. The TPM sensor can be forced to transmit by using a special tool such as a
TPM-RKE Analyzer, or from a transponder. The TPM-RKE Analyzer has the ability to change the sensor's operating mode to PARK MODE and to help
diagnose a faulty TPM sensor. Using a TPM-RKE Analyzer can take up to a minute to force a transmission from a sensor.
The TPM sensor can be in one of the following operating modes:
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SLEEP MODE - This is the operating mode of a new TPM sensor. If placed on the vehicle as a road tire, the sensor will transmit once every 20
seconds when the vehicle is driven at speeds over 15 mph (24 km/h). Driving the vehicle continuously at this speed for more then 4 minutes will
change the sensor state to DRIVE MODE. Stopping the vehicle for 20 minutes will change the sensor state to PARK MODE. If the vehicle is not
moving, the sensor will only transmit on a pressure change greater then 1 psi (6.9 kPa).
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PARK MODE - This is the correct operating mode when the vehicle is not moving. The sensor will transmit once every 13 hours to update the
WCM, or will transmit on a 1 psi (6.9 kPa) delta change. The sensors will internally take a measurement of the tire pressure every minute to
determine a change in tire pressure.
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30 BLOCK MODE - If the vehicle has been stopped for more then 20 minutes, or if the sensor's operating mode was forced to PARK MODE
using a TPM-RKE Analyzer, the sensor's operating mode will transition from PARK MODE to 30 BLOCK MODE once the vehicle is driven over
15 mph. In this mode, the sensor will transmit once every 15 seconds when the vehicle is driven at speeds over 15 mph (24 km/h) for the first 30
transmissions. After about 8 minutes of continuous driving above 15 mph (24 km/h), the sensor's mode will change to DRIVE MODE.
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DRIVE MODE - In this mode, the sensor will transmit once every minute when the vehicle is driven at speeds over 15 mph (24 km/h). At any
time the vehicle speed drops below 15 mph, the sensor will not transmit. The sensor mode will still be in drive mode when the sensor reaches
speeds over 15 mph (24 km/h), unless the vehicle has been stationary for more then 20 minutes.
Each sensor's (transmitter) broadcast is uniquely coded so that the wireless control module (WCM) can monitor the state of each of the sensors on the
four rotating road wheels. The WCM can automatically learn and store the sensor's ID while driving "within 10 minutes continuously above 15 mph (24
Km/h)" after a sensor has been replaced. The vehicle must be stationary for more then 20 minutes in order to initiate the learning sequence. The WCM
can also learn the sensor's ID using the TPM-RKE Analyzer, Special Tool 9936, with the Scan Tool following the procedure listed in the appropriate
diagnostic information.
