TIRE PRESSURE MONITORING SYSTEM (TPMS) OPERATION
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• The instrument cluster monitors the tire pressure of each tire and the wheel units for abnormalities using the received data. If any abnormality is found, it controls TPMS warning light to alert and notify the driver.
• The instrument cluster controls the following functions based on the received data:
Function list
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Identification code recognition function
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• Recognizes whether received signals are from own wheel units.
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Tire pressure determination/warning function
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• Compares received tire pressure data with preset values. If the pressure is determined to be too low, the instrument cluster alerts the driver via the TPMS warning light.
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Identification Code Recognition Function
• Since the identification codes of wheel units mounted on the vehicle have been configured in the instrument cluster, the instrument cluster can verify the identification codes sent from the wheel units against the configured identification codes.
• When the received identification code agrees with the configured identification code, data such as tire pressure is updated according to the received signal. When the identification code does not agree, that signal data is ignored.
Tire Pressure Determination And Warning Function
• The instrument cluster determines the tire pressure status of each wheel by comparing tire pressure data received from the wheel units with the preset values in the instrument cluster.
• If a malfunction is detected in the received signals, the instrument cluster flashes the TPMS warning light to notify the driver of a tire malfunction.
• The informing/warning of an abnormal tire pressure determination takes precedence over the informing/warning of a missing signal or malfunction determination.
Low-pressure determination
• When tire pressure data is lower than the detection value configured in the instrument cluster, the instrument cluster determines that the tire for that wheel unit has low tire pressure.
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― If low tire pressure is determined when the ignition is on, the TPMS warning light is illuminated.
― If low tire pressure is determined when the ignition is off, the instrument cluster performs an open-circuit check*1 on the TPMS warning light after the ignition is turned on, and then illuminates the TPMS warning light.
• The low-pressure determination is retained until tire pressure data from the applicable wheel unit returns to the preset value.
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― If tire pressure data that is higher than the specified value is received when the ignition is on, the TPMS control module turns out the TPMS warning light.
― If tire pressure data that is higher than the specified value is received when the ignition is off, the module performs an open-circuit check
*1 on the TPMS warning light after the ignition is turned on and turns out the TPMS warning light.
*1: The TPMS control modules turns on the TPMS warning light for 3 s after the ignition is turned on for an open-circuit check of the TPMS warning light.
