TIRE PRESSURE WARNING SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Tire Pressure Warning Valve and Transmitter Detects the pressure, internal temperature and rotational acceleration of the tire, and transmits the measured values and the ID code to the tire pressure monitor receiver assembly.
    No. 1 Tire Pressure Warning Switch The warning threshold is calculated from the tire inflation pressure value at the time of initialization and memorized in the tire pressure monitor receiver assembly by operating the no. 1 tire pressure warning switch.
    Tire Pressure Monitor Receiver Assembly

    • Receives the data from the tire pressure warning valve and transmitter 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.
    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).
    Speedometer Sends a vehicle speed signal to the tire pressure monitor receiver assembly.

  2. FUNCTION


    1. Warning Function


      1. The tire pressure monitor receiver assembly has 2 warning methods depending on the condition detected.

      2. The table below shows the warning methods for the tire pressure warning light in the combination meter assembly.

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

        Tech Tips

        *1: If the tire pressure warning light illuminates, adjust the tire 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. For details, refer to the Repair Manual.

    2. Initial Check Function


      1. After the ignition switch is ON, the tire pressure monitor receiver assembly illuminates the tire pressure warning light for 3 seconds to check the warning light circuits.

    3. Initialization Function


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


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

        • The tire pressure monitor receiver assembly 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.*

        Tech Tips

        *: Models compliant with ECE-R64 legal regulations

      2. Initialization starts after the no. 1 tire pressure warning switch is pressed and held (with the ignition switch ON 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 no. 1 tire pressure warning switch is not used to cancel the warning. Do not press the no. 1 tire pressure warning switch to turn off the tire pressure warning light.

  3. CONSTRUCTION


    1. Tire Pressure Monitor Valve Sub-assembly


      1. The tire pressure monitor valve sub-assemblies are integrated in the tire valves. Each tire pressure monitor valve sub-assembly consist 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 antenna at a frequency of 433.90 MHz.*

        Tech Tips

        *: Models compliant with ECE-R64 legal regulations

      5. Depending on the timing of the data transmission, it may take several minutes to receive the data from the tire pressure monitor valve sub-assembly.

      6. The ID code is written on the tire pressure monitor valve sub-assembly.

        A005FW7E02
        Text in Illustration
        *1 Tire Pressure Monitor Valve Sub-assembly *2 Grommet
        *3 Washer *4 Nut
        *5 Tire Valve Core *6 Cap
        *7 Lithium Battery *8 Sensor and Transmitter
        *9 ID Code (7 Digit Hexadecimal) - -

        Tech Tips


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

        • A new tire pressure monitor valve sub-assembly is shipped in sleep mode to prevent the battery from depleting in storage. When the pressure in the detection portion of the tire pressure monitor valve sub-assembly decreases by 40 kPa (5.8 psi, 0.4 bar) within 30 seconds, the tire pressure monitor valve sub-assembly automatically cancels sleep mode. Once sleep mode is canceled, the tire pressure monitor valve sub-assembly cannot return to sleep mode.

        • When replacing a tire pressure monitor valve sub-assembly, the ID codes of each tire pressure monitor valve sub-assemblies must be registered. If even one of the tire pressure monitor valve sub-assemblies is replaced, the ID codes of all tire pressure monitor valve sub-assemblies must be registered again. Record all existing ID codes before beginning the process to enter new ID codes.

        • To register an ID codes, use the Global TechStream (GTS) to enter the ID codes that are indicated on the tire pressure monitor valve sub-assembly.

        • Be careful not to damage the tire pressure monitor valve sub-assembly when removing and reinstalling them.

        • Replace the grommet, valve core, washer and nut with new ones when replacing or removing and reinstalling the tire pressure monitor valve sub-assembly. This is necessary to ensure sealing performance.

        • When replacing a valve cap, use only the specified cap. If an unspecified cap is used, it may seize to the tire pressure monitor valve sub-assembly.

        • For details, refer to the Repair Manual.

  4. DIAGNOSIS


    1. To inform the driver when the tire pressure monitor receiver assembly detects a malfunction in the system, the tire pressure monitor receiver assembly blinks the tire pressure warning light for 1 minute, after which the light stays on. The tire pressure monitor receiver assembly also stores 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.