TIRE PRESSURE WARNING SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Tire Pressure Warning Valve and Transmitter

    • Detects the tire pressure, internal temperature and rotational acceleration of the tire, and transmits the measured values and the ID code to the tire pressure warning ECU and receiver via the tire pressure warning antenna.

    • Receives electrical waves for tire position determination from the initiators.
    Tire Pressure Warning Roof Antenna Receives the tire pressure warning valve and transmitter signal and transmits this data to the tire pressure warning ECU and receiver.
    Tire Pressure Warning Front Antenna Receives the tire pressure warning valve and transmitter signal and transmits this data to the tire pressure warning ECU and receiver.
    Tire Pressure Warning Front Initiator Built into the front-right wheelhouse and sends the electrical waves for tire position determination to the sending devices (tire pressure warning valve and transmitter).
    Tire Pressure Warning Rear Initiator Built into the rear-right wheelhouse and sends the electrical waves for tire position determination to the sending devices (tire pressure warning valve and transmitter).
    Tire Pressure Warning Initiator Driver Operates the tire pressure warning initiators.
    Tire Pressure Warning ECU and Receiver

    • Receives the data from the tire pressure warning valve and transmitter via the tire pressure warning antenna and monitors the tire inflation pressure.

    • Outputs the respective signal to the combination meter assembly when a drop in the tire inflation pressure, a system malfunction or the beginning of initialization is detected.

    • Instructs the initiator driver to determine tire positions.

    • Confirms the positions of the tires in accordance with information about the intensity of electrical waves for tire position determination from the tire pressure warning valve and transmitter, and sends a signal to display the tire pressure value (based on the measured value) on the multi-information display.
    Tire Pressure Warning Reset Switch The warning threshold is calculated from the tire inflation pressure value at the time of initialization and memorized in the tire pressure warning ECU and receiver by operating the tire pressure warning reset switch.
    DISP Switch Switches the information on the multi-information display to the tire pressure when pressed.
    Main Body ECU (Driver Side Junction Block) Receives a signal from tire pressure warning ECU and receiver and outputs the signal to the combination meter assembly via CAN communication.
    Combination Meter 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 system.

    • Flashes 3 times after initialization.

    • Displays the 2-digit Diagnostic Trouble Code (DTC).
    Multi-information Display Displays the identified tire pressure and position to inform or warn the driver.
    Speedometer Sends a vehicle speed signal to the tire pressure warning ECU and receiver.

  2. FUNCTION


    1. Tire Inflation Pressure Display Function


      1. The multi-information display shows the following to inform or warn the driver of the tire pressure:

        Condition Multi-information Display*
        Tire pressure is normal. A000M6T
        Tire pressure warning reset switch is pressed. A000MOV

        Tech Tips

        *: These illustrations are examples for models for Europe. The spare tire display is shown on models with a full size spare tire only.

      2. Identification of the tire position is carried out when the power switch is turned on (IG), when initializing or when registering ID codes. However, under certain conditions, the tire position may not be displayed. In that case, electric wave conditions may be restored by continuously driving to enable the tire position determination.

    2. Warning Function


      1. The tire pressure warning ECU and receiver has 2 warning methods, depending on the condition detected.

      2. The table below shows the warning methods for the tire pressure warning light and multi-information display in the combination meter assembly:

        Detection Condition Tire Pressure Warning Light Multi-information Display*1
        The tire pressure warning system has detected that the tire pressure has become lower than the warning threshold. Illuminates*2 A000MEQ
        The tire pressure warning system has detected a malfunction in the system. Illuminates after blinking for 1 minute*3 A000MHS

        Tech Tips

        *1: These illustrations are examples for models for Europe. The spare tire display is shown on models with a full size spare tire only.

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

        *3: If the tire pressure warning light stays on after blinking for 1 minute, the system is malfunctioning and must be repaired in order to turn off the light. For details, refer to the Repair Manual.

    3. Initial Check Function


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

    4. Initialization Function


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


        • The recommended tire inflation pressure changes due to changes in vehicle weight, speed conditions or tire size.

        • The tire pressure warning ECU and receiver or the tire pressure warning valve and transmitter are replaced.

        • The tires are rotated on a vehicle with different recommended tire inflation pressures for the front and rear tires.

        • The tire pressure is adjusted.*


        • *: Models compliant with ECE-R64 legal regulations, except models for China

      2. Initialization starts after the tire pressure warning reset switch is pressed and held (with the power switch on (IG) and with the vehicle stopped) and the tire pressure warning light illuminates slowly 3 times.

      3. Before performing initialization, adjust the tire inflation pressure to the recommended pressure when the tires are cold. For details, refer to the Repair Manual.

      4. The tire pressure warning reset switch is not used to cancel the warning. Do not press the tire pressure warning reset switch to turn off the tire pressure warning light.*


        • *: Models compliant with FMVSS138 legal regulations for China

  3. CONSTRUCTION


    1. Tire Pressure Warning Valve and Transmitter


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

      2. Make sure not to damage the urethane-covered backside of the transmitter (the surface opposite to the side with the ID code) with anything sharp.

      3. The transmitter directly measures tire inflation pressure and temperature to see if the vehicle can continue to run.

      4. 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.


        • *1: Models for Central and South America, Thailand, Taiwan and China

        • *2: Except models for Central and South America, Thailand, Taiwan and China

      5. Depending on the timing of the data transmission, it may take several minutes to receive the data from the tire pressure warning valve and transmitter.

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

      7. Signals are received from the tire pressure warning initiator.

        A000M3WE06
        Text in Illustration
        *1 Tire Pressure Warning Valve and Transmitter *2 Grommet
        *3 Washer *4 Nut
        *5 Tire Valve Core *6 Tire Valve Cap
        *7 Lithium Battery *8 Sensor and Transmitter
        *9 ID Code (Hexadecimal 7 Digits) - -

        Tech Tips


        • The lithium batteries of the tire pressure warning valve and transmitters are non-replaceable. If the battery is depleted, the tire pressure warning valve and transmitter must be replaced (battery life: approximately 10 years).

        • A new tire pressure warning valve and transmitter is shipped in sleep mode to prevent the battery from depleting in storage. When the tire inflation 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.

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

        • To register an ID code, use a Global TechStream (GTS) to enter the ID code that is indicated on the tire pressure warning valve and transmitter.

        • Be careful not to damage the tire pressure warning valve and transmitters when removing and reinstalling them.

        • Replace the grommet, valve core with new ones when replacing or removing and reinstalling the tire pressure warning valve and transmitter. This is necessary to ensure sealing performance.

        • When replacing a valve cap, use only a specified cap. If an unspecified cap is used, it may stick to the tire pressure warning valve and transmitter.

        • 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 blinks the tire pressure warning light for 1 minute, after which the light stays on. The tire pressure warning ECU and receiver also stores the Diagnostic Trouble Codes (DTCs) in memory.

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