TIRE PRESSURE WARNING SYSTEM SYSTEM DESCRIPTION


  1. DESCRIPTION OF SYSTEM


    1. When the tire pressure warning system detects that the tire pressure of a tire is lower than the threshold, it will inform the driver using a warning light.

    2. The tire pressure warning ECU and receiver receives the transmitter ID, temperature and tire pressure information from the tire pressure warning valve and transmitters shown in the following illustration. This information is used to determine when the pressure in one of the tires has dropped.

      B003YLOC01
      *1 Tire Pressure Warning ECU and Receiver *2 Tire Pressure Warning Valve and Transmitter
      *3

      Combination Meter Assembly

      - Tire Pressure Warning Light

      		 *4 Main Body ECU (Multiplex Network Body ECU)
      *5 Tire Pressure Warning Reset Switch *6

      w/ Tire Inflation Pressure Display Function:

      Tire Pressure Monitor Initiator Driver
      *7

      w/ Tire Inflation Pressure Display Function:

      Front Tire Pressure Monitor Initiator

      		 *8

      w/ Tire Inflation Pressure Display Function:

      Rear Tire Pressure Monitor Initiator
      *a Front *b

      w/ Tire Inflation Pressure Display Function:

      Tire Position Identification Signal

  2. DESCRIPTION OF TIRE POSITION IDENTIFICATION FUNCTION (w/ Tire Inflation Pressure Display Function)


    1. The deterioration of signal strength at a distance (when a transmitter is close, the signal is strong, and when a transmitter is far, the signal is weak) is used to determine position. Position identification is performed when the engine switch is turned on (IG), when the vehicle starts moving (if the position could not be determined when the engine switch was turned on (IG)), when initialization is performed and when ID registration is completed.

      For front position identification (rear position identification is performed in the same way):


      1. The front tire pressure monitor initiator sends a position identification signal to all of the tire pressure warning valve and transmitters.

      2. The tire pressure warning valve and transmitters respond to the received position identification signal by sending a signal to the tire pressure warning ECU and receiver indicating the strength of the received signal.

        Tech Tips

        The strength of the signals is different because the distance between the front tire pressure monitor initiator and each tire is different.

      3. The tire pressure warning ECU and receiver receives the signal strength information signals from the tire pressure warning valve and transmitters and associates them with their correct position based on the received information.

  3. DESCRIPTION OF REGISTRATION


    1. When tires and wheels are replaced, always ensure that each transmitter ID is correctly registered.

    2. When one or more of the tire pressure warning valve and transmitters or the tire pressure warning ECU and receiver is replaced, the transmitter IDs for all of the tire pressure warning valve and transmitters must be re-registered. Before registering the transmitter ID of the new tire pressure warning valve and transmitter, check the Data List and record all of the transmitter IDs that are already registered.

  4. TIRE PRESSURE WARNING RESET SWITCH


    1. By operating the tire pressure warning reset switch, the tire pressure warning ECU and receiver can be set to issue a warning at an inflation pressure that corresponds to the type of tires fitted to the vehicle. Therefore, the warning threshold must be set to the proper value in order to comply with local regulations.

    2. Operate the tire pressure warning reset switch only after the inflation pressures of all tires (except the compact spare tire) have been adjusted on the vehicle.

  5. DESCRIPTION OF INITIALIZATION


    1. During initialization, the tire pressure warning valve and transmitters measure the inflation pressure of the tires, and register the signals that are transmitted into the tire pressure warning ECU and receiver at a frequency of about once per minute. The initialization process is completed when signals from all tires (except the compact spare tire) have been received.

    2. Perform initialization in the following cases:


      1. Before delivery of a new vehicle.

      2. After replacement of the tire pressure warning ECU and receiver*.

      3. After replacement of a tire pressure warning valve and transmitter*.

      4. When the specified tire pressure changes due to the use of a different size or type of tire.

      5. When the specified tire pressure changes due to a change in the vehicle load, the speed range that the vehicle will be used in, etc.

      6. When a tire rotation is performed and the specified tire pressures are different for the front and rear of the vehicle.

        Tech Tips

        *: Perform initialization after the transmitter ID registration is completed.

  6. DESCRIPTION OF ID SWITCHING FUNCTION (w/ ID Switching Function)


    1. By designating the ID registration location, it is possible to register transmitter IDs for both the main and 2nd sets of tires.

    2. If IDs are registered for both the main and 2nd tire sets, it is possible to switch between the two sets of tires by pressing the tire pressure warning reset switch.

      Click here

      Note

      Be careful as the method to perform ID switching differs from the method to perform initialization.

    3. When reading the status for a registered ID, it is only possible to read the ID information for the selected set of tires.

      Tech Tips

      In order to read the IDs registered for the main tire set, it is necessary to set the ID selection setting to "Main". Likewise, it is necessary to set the ID selection setting to "2nd" in order to read IDs registered for the 2nd set of tires.

  7. FUNCTION OF MAIN COMPONENTS

    Component Function
    Tire Pressure Warning ECU and Receiver

    • Receives data from each tire pressure warning valve and transmitter and monitors the tire pressures.

    • When the tire pressure warning ECU and receiver detects a drop in the tire pressure, a system malfunction, or initialization mode, it outputs the respective signal to the combination meter assembly.

    • When the tire pressure warning ECU and receiver detects that the vehicle speed signal is lost, it determines that the vehicle is being driven.

    w/ Tire Inflation Pressure Display Function:


    • Commands the tire pressure monitor initiator driver to perform position identification.

    • Associates each tire pressure warning valve and transmitter with a certain position (left/right and front/rear) based on the signal strength information received from each tire pressure warning valve and transmitter, and outputs tire pressure information to the multi-information display.
    Tire Pressure Warning Valve and Transmitter

    Detects the pressure and internal temperature of the tire and transmits the measured values and the ID code to the tire pressure warning ECU and receiver.

    w/ Tire Inflation Pressure Display Function:

    Receives position identification signals from the front and rear tire pressure monitor initiators and sends a signal indicating the signal strength to the tire pressure warning ECU and receiver.
    Tire Pressure Warning Reset Switch

    • Stores the warning threshold determined by the current tire pressure as the set pressure in the tire pressure warning ECU and receiver when operated.

    • Pressing this switch performs ID switching (w/ ID Switching Function).

    w/ Tire Inflation Pressure Display Function:


    • Front Tire Pressure Monitor Initiator

    • Rear Tire Pressure Monitor Initiator

    		 Sends a position identification signal to the tire pressure warning valve and transmitters.

    w/ Tire Inflation Pressure Display Function:

    Tire Pressure Monitor Initiator Driver

    		 Operates and monitors the front and rear tire pressure monitor initiators.
    Combination Meter Assembly Transmits the vehicle speed signal to the tire pressure warning ECU and receiver.
    Tire Pressure Warning Light

    • Illuminates after blinking for 1 minute to warn the driver in accordance with the signal from the tire pressure warning ECU and receiver.

    • Displays 2-digit Diagnostic Trouble Codes (DTCs).
    Main Body ECU (Multiplex Network Body ECU)

    • The main body ECU (multiplex network body ECU) and tire pressure warning ECU and receiver are connected using 2 direct lines that they use to communicate with each other.

    • The main body ECU (multiplex network body ECU) is connected to the combination meter assembly via CAN bus.