Operation CHARM: Car repair manuals for everyone.

Wireless Control Module (WCM)






WIRELESS CONTROL MODULE (WCM)

The receiver circuit for the TPM system is integrated into the WCM. The WCM also includes the Remote Keyless Entry (RKE) receiver and the Sentry Key Immobilizer (SKIM) receiver. All three receivers share a number of common components. The WCM decodes the RF signals transmitted by each of the vehicle's tire pressure sensors. The decoded information is used to determine if "warning" or "fault" conditions exist within the TPM system.


The WCM communicates with the module that controls the "TPM telltale lamp", via the vehicle bus system.


Upon detection of a warning or fault condition, the WCM will send a request to illuminate or flash the yellow TPM telltale. Also, upon detection of a warning or fault condition, the display module will send a request to sound the "chime". A chime will only be requested once per ignition cycle per warning or fault condition detected.


The WCM will store all warning and fault conditions, placard pressure values, low-pressure threshold values and low pressure threshold hysteresis values in memory that can be accessed through diagnostic communication. If new sensors are introduced to the vehicle, the data stored for the sensor being replaced will be deleted.


The WCM will store all wheel sensor ID's and locations and faults in memory that can be accessed through diagnostic communication. All other data values transmitted from each active wheel sensor (not the spare tire) shall be stored in the WCM memory.


The WCM automatically learns and stores the sensor's ID while driving "within 10 minutes continuously above 15 m.p.h. (24 Km/h)" after a sensor has been replaced.


The learning sequence will initiate when the vehicle has been stopped for more then 20 minutes.