TIRE PRESSURE WARNING SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Tire Pressure Warning ECU and Receiver

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

    • Outputs the respective signal to the combination meter sub-assembly when a drop in the tire inflation pressure, a system malfunction or the beginning of initialization is detected.
    Tire Pressure Warning Valve and Transmitter Detects the tire inflation pressure and temperature of the tire and transmits the measured value and ID code to the tire pressure warning ECU and receiver.
    Tire Pressure Warning Reset Switch The appropriate tire inflation pressure for the tires currently mounted on the vehicle are stored in the tire pressure warning ECU and receiver by operating the tire pressure warning reset switch.
    Combination Meter Sub-assembly Transmits the vehicle speed signal to the tire pressure warning ECU and receiver.
    Combination Meter Sub-assembly Tire Pressure Warning Light Illuminates or stays on after blinking for 1 minute to warn the driver in accordance with the signal from the tire pressure warning ECU and receiver.

  2. FUNCTION


    1. Warning Function


      1. The tire pressure warning ECU and receiver has 3 warning methods that are used, depending on the condition detected.

        Tire Pressure Warning Light Detection Condition
        Illuminates*1 The tire pressure warning ECU and receiver has detected that the inflation pressure of a tire has become lower than the threshold.
        Stays on after blinking for 1 minute*2 The tire pressure warning ECU and receiver has detected a malfunction in the system.
        Blinks 3 times When the tire pressure warning reset switch pressed.

        Tech Tips

        *1: If the tire pressure warning light illuminates, adjust the tire inflation pressure.

        *2: If the tire pressure warning light stays on after blinking for 1 minute, the system is malfunctioning and must be repaired to turn off the light.

    2. Initial Check Function


      1. After turning the power switch on (IG), the tire pressure warning ECU and receiver illuminates the tire pressure warning light for 3 seconds to check the warning light circuit.

    3. Initialization Mode Function


      1. The warning threshold is calculated from the tire inflation pressure and memorized in the tire pressure warning ECU and receiver. Therefore, the tire pressure warning ECU and receiver should be initialized after:


        • The specified tire inflation pressure value changes according to vehicle weight or speed conditions or the value changes as a result of a different tire size.

        • Tire rotation when the preset tire inflation pressure differs between the front and rear.

        • Replacement of the tire pressure warning ECU and receiver or a tire pressure warning valve and transmitter.

      2. Adjust the tire inflation pressure to the specified cold tire inflation pressure before performing initialization. For the initialization procedure, refer to the Repair Manual.

  3. CONSTRUCTION


    1. Tire Pressure Warning Valve and Transmitter


      1. The tire pressure warning valve and transmitters are integrated in the tire valves. Each tire pressure warning valve and transmitter consists of a lithium battery, sensor and transmitter.

      2. The tire pressure warning valve and transmitter directly measures tire inflation pressure and temperature.

      3. The transmitter transmits the measured tire inflation pressure and temperature values to the tire pressure warning ECU and receiver on a frequency of 314.98 MHz*1 or 433.90 MHz*2.

        Tech Tips

        *1: Destination package for Taiwan

        *2: Except destination package for Taiwan

      4. The reception of a signal from a tire pressure warning valve and transmitter may be delayed by a few minutes due to the timing of data transmission.

      5. The ID code is written on the tire pressure warning valve and transmitter.

        A0050Q7E03
        Text in Illustration
        *1 Tire Pressure Warning Valve and Transmitter *2 Washer
        *3 Nut *4 Tire Valve Core
        *5 Cap *6 Lithium Battery
        *7 Sensor and Transmitter *8 ID Code (Hexadecimal 7 Digits)

        Tech Tips


        • The lithium batteries of the tire pressure warning valve and transmitters are non-replaceable. If a battery is depleted, the tire pressure warning valve and transmitter must be replaced.

        • A new tire pressure warning valve and transmitter is shipped in sleep mode to prevent the battery from depleting in storage. When the pressure in the detection portion of the tire pressure warning valve and transmitter increases or decreases by 40 kPa (0.4 kgf/cm2, 5.8 psi) within 30 seconds, the tire pressure warning valve and transmitter automatically cancels sleep mode. Once sleep mode is canceled, the tire pressure warning valve and transmitter cannot return to sleep mode.

        • After a tire pressure warning valve and transmitter is replaced, the ID code of the tire pressure warning valve and transmitter must be registered in the tire pressure warning ECU and receiver. To register an ID code, use the Global TechStream (GTS) to enter the ID code that is indicated on the tire pressure warning valve and transmitter.

        • When replacing a tire pressure warning valve and transmitter, the ID codes of each tire pressure warning valve and transmitter must be registered. Even if only 1 tire pressure warning valve and transmitter is replaced, the ID codes of all the tire pressure warning valve and transmitters must be registered again. Record all existing ID codes before beginning the process to enter new ID codes.

        • Replace the grommet when the tire pressure warning valve and transmitter is being replaced to ensure the sealing performance. Note that the grommet is not reusable.

        • When replacing tire valve caps, do not use tire valve caps other than those specified. The cap may become stuck.

        • Be careful not to damage the tire pressure warning valve and transmitters during tire removal or installation.

        • For details, refer to the Repair Manual.

  4. DIAGNOSIS


    1. To inform the driver when the tire pressure warning ECU and receiver detects a malfunction in the system, the tire pressure warning ECU and receiver will blink the tire pressure warning light for 1 minute, after which the light will stay on. The tire pressure warning ECU and receiver will also store Diagnostic Trouble Codes (DTCs) in memory.

    2. 5-digit DTCs can be read by connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.