Tire Pressure Module: Description and Operation

TPMS RECEIVER
DESCRIPTION
RECEIVER





1. Mode
1) Virgin State (No TPMS sensor ID's learned)
- 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 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.
- In unlearned state when connected in the vehicle with ignition key on the TPMS lamp will flash at one second intervals.





2) Normal State
- In order for tire inflation state and DTC monitoring to occur, the receiver must be in this state.
- In this state type 1, 2, or 3 sensor learning mode can be started.





2. Overview
- Receives RF data from sensor.
- Uses sensor data to decide whether to turn on TREAD Lamp.
- Uses sensor information, 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.
- Activates LFI for TPMS sensor location.

LFI (LOW FREQUENCY INITIATOR)





1. Overview
- Only High Line systems are fitted with an LFI.
- The LFI is located in the wheel well of each tire, to enable the receiver to determine the vehicle position of each TPMS sensor for which it has a stored TPMS sensor ID code.
- When first turned on, the receiver activates the LFI's to wake up the TPMS sensors and get wheel status.
- The LFI's are activated every 10 minutes to keep the TPMS sensors awake while the key is on.
2. Operating mode
- When triggered by the receiver the LFI broadcasts a 125 KHz signal through the tire to the TPMS sensors to wake them up sequentially.
- After broadcasting the LFI returns to sleep mode until triggered again by the receiver.
- Once the TPMS sensor has received the 125 KHz wake up signal, it broadcasts it's ID and status. This information plus which LFI triggered it allows the receiver to record which tire has which sensor.





OPERATION
1. Type 1 learn mode
- TPMS sensor learning via K-line diagnostic bus using TPMS Exciter.
2. Type 2 learn mode
- Learn via LFI wand
- Enter type 2 learn mode via K-line command.
- Trigger each TPMS sensor in the following order FL, FR, RL, RR with the LFI wand.
- Exit type II learn mode.
3. Type 3 learn mode (High line only)
- Enter type 3 learn mode via K-line command.
- Receiver triggers each LFI and programs TPMS sensors and received.

CAUTION:
- If a vehicle equipped with TPMS is aside the vehicle being inspecting, the TPMS sensor may be learned in correctly.
- If a TPMS sensor of other vehicle is in the magnetic field of the LFI, the sensor ID may be learned.