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.

    • Receives electrical waves for tire position determination from the initiators.
    Front Tire Pressure Warning Initiator* Built into the front-left wheelhouse and sends the electrical waves for tire position determination to the sending devices (tire pressure warning valve and transmitter).
    Rear Tire Pressure Warning Initiator* Built into the rear-left 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 and monitors the tire inflation pressure.

    • Outputs the respective signal to the main body ECU (multiplex network body ECU) 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.*
    Steering Pad Switch Assembly

    • Switches the information on the multi-information display to the tire pressure when pressed.*

    • By operating the switch on the setting screen of the multi-information display, the tire pressure warning thresholds according to the current tire pressure is stored as a set pressure in a tire pressure warning ECU and receiver.
    Main Body ECU (Multiplex Network Body ECU) Receives the signal from tire pressure warning ECU and receiver and outputs it to the combination meter assembly via CAN communication.
    Combination Meter Assembly Transmits the vehicle speed signal to the tire pressure warning ECU and receiver.
    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.

    • Blinks 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.*

    • Displays the initialized operation for the tire pressure warning system.

    *: Models with tire inflation pressure display function

  2. FUNCTION


    1. Tire Inflation Pressure Display Function (Models with 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. A01QDIT
        Tire pressure is below the warning threshold. A01QDPX
        There is a system malfunction, or tire position identification has not yet been completed. A01QDO1

        *: This illustration is an example.

      2. Identification of the tire position is carried out when the engine switch is turned on (IG), initialization is performed, or the transmitter ID code is registered. 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. When any of the following conditions are met, the tire pressure warning system illuminates the tire pressure warning light to warn the driver.

        Warning Condition (Models Compliant with FMVSS138 Legal Regulations)

        • When the tire pressure decreases to approximately 75% or less of the default tire pressure set during system initialization.

        Tech Tips

        The warning pressure (pressure at which the tire pressure warning light illuminates) is not set to a tire pressure that is approximately 75% or less of the specified tire pressure.

        Warning Condition (Models Compliant with ECE-R64 Legal Regulations)

        • When the tire pressure decreases to approximately 80% or less of the default tire pressure set during system initialization.

        • When the tire pressure decreases rapidly (approximately 20 kPa or more over a period of several minutes) and drops below approximately 80% or less of the tire pressure when warm.

        Tech Tips


        • When driving for a certain period of time after the system has been initialized, the system corrects the tire pressure set during initialization according to the vehicle driving conditions and sets the tire pressure when warm.

        • The warning pressure (pressure at which the tire pressure warning light illuminates) cannot be set to a tire pressure of the lower threshold or less.

        A01QDHEE06

      2. The tire pressure warning system has 2 warning methods which are used depending on the condition detected.

      3. 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, *2
        The tire pressure warning system has detected that the tire pressure has become lower than the warning threshold. Illuminates*3 A01QDPX
        The tire pressure warning system has detected a malfunction in the system. Illuminates after blinking for 1 minute*4 A01QDO1

        *1: Models with tire inflation pressure display function

        *2: This illustration is an example.

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

        *4: 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 engine 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 valve 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.

        • 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

      2. When the steering pad switch assembly is operated with the engine switch on (IG) and the vehicle in the stopped state, the tire pressure warning system initialization screen is displayed on the multi-information display, and the initialization setup is performed when the ENTER button is pressed and held. A warning threshold value is calculated from the tire pressure when initialized and is saved as the standard pressure by the tire pressure warning ECU and receiver. Also, when the initialization command is normally received, "Tire Pressure Recalibrating. Please Wait Until Complete" is indicated in the multi-information display.

      3. Initialization is complete when signals are received from all of the tires. If the engine switch is turned off during the initialization, it is not necessary to re-initialize after the engine switch is turned on (IG), as the system remembers it was in the process of initializing.

      4. After running for approximately 20 minutes, if the tire pressure warning light blinks and then comes on after that, the initialization has not been completed normally, so it is necessary to re-initialize.

  3. 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. It will also store 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.