Tire Pressure Module: Description and Operation

TPMS RECEIVER

DESCRIPTION





1. Mode
1) Virgin State
^ The receiver as a sole part is shipped in this state. Replacement parts should therefore arrive in this state.
^ In this state, there is no Auto-Location, no sensor wake-up, no sensor monitoring and no DTC monitoring.
^ The state indicates that platform specific parameters must be written to the receiver and that sensors are un-learned.





2) Normal State
^ In order for tire inflation state and DTC monitoring to occur, the receiver must be in this state.
^ In this state, automatic sensor location / learning is enabled.





2. Overview
^ Sends LF command data to initiators.
^ Controls sensor state:

Ignition on - Normal Delayed

Ignition off - Storage.

^ Auto-Locates sensors.
^ Auto-Learns new sensors.
^ Receives RF data from sensor.
^ Uses sensor data to decide whether to turn on TREAD Lamp / wheel location LED's.
^ Uses sensor information, distance traveled, background noise levels, Auto-learn status, short circuit output status, vehicle battery level, internal receiver states to determine if there is a system or a vehicle fault.

OPERATION
1. General Function
^ Auto-locate/learn takes place only once per Ignition cycle.
^ On successful completion, 4 road wheel sensor ID's + 1 spare, together with their respective road wheel positions are latched into memory for monitoring.
^ Until Auto-learn completes, previously learned sensors (together with their respective locations) are monitored for under inflation / leak warnings.
^ Spare tire inflation / DTC state is not displayed.
^ Spare tire DTC's are available through diagnostics only.
2. General Conditions to Learn New Sensors:
^ Receiver must Auto-Locate 4 road sensors.
^ Auto-location / learning only functions when speed is more than 20 kph (approx. 15 mph).
^ Receiver must determine that it is confident that sensor is not temporary:
a) Uses vehicle speed.
b) Uses confidence reduction of previously learned sensors.
^ Typical time at driving over 20 kph to learn a new sensor is up to 10 minutes.
3. General Conditions to Un-Learn a sensor that is removed:
^ It takes less than 10 minutes at 20 - 30 kph.
^ Confidence reduction is dependant on vehicle speed and the number of sensors known to the receiver.