Operation; Component Parts/Function; Wheel Unit; Construction - Mazda RX-8 2004 Service Highlights

Operation

• The wheel unit installed to each wheel sends data on air pressure, temperature and acceleration of each tire by
means of RF signals. The TPMS control module receives these signals with a built-in antenna.
• The TPMS control module monitors the air pressure of each tire based on the tire data sent from each wheel
unit. If the module detects an excessive drop in air pressure or air pressure higher than a specified value, the
module illuminates the TPMS warning light and sounds the TPMS warning buzzer via CAN communication to
alert the driver.

Component Parts/Function

Part name

Wheel unit

TPMS control module
PCM Vehicle speed signal
TPMS warning light
Instrument
cluster
TPMS warning buzzer
End Of Sie
WHEEL UNIT CONSTRUCTION/OPERATION

Construction

• The wheel unit is installed to the rim of each wheel with a nut. It monitors air pressure, temperature and
acceleration of the tire, and sends the data as RF signals.
• The wheel unit also serves as a tire valve.
Operation
• The wheel unit operates on a built-in battery, and regularly sends tire data as RF signals. The data it sends is
retrieved using a sensing function that monitors tire pressure and temperature, and a self-diagnostic function
that detects battery status and sensor malfunction.
• To maximize the life of the built-in battery, the unit uses the detected air pressure and acceleration to determine
vehicle conditions such as driving and long stops, and operates in a mode appropriate to vehicle conditions so
that battery consumption is minimized.
• Each wheel unit has its own identification code that is sent together with tire data and is used to verify which tire
has abnormal tire pressure. Therefore, when the wheel unit or the TPMS control module is replaced, the
identification codes must be configured.
WHEEL AND TIRES
• Monitors air pressure, temperature, and acceleration of each tire, and sends
RF signals.
• Sends data if any abnormality is detected in the wheel unit.
• Receives RF signals from the wheel units and monitors the air pressure of each
tire. If it determines from these signals that tire pressure is abnormal, it controls
the TPMS warning light and buzzer via CAN communication to alert the driver.
• Controls the on-board diagnostic system if it receives an abnormal signal from
the wheel unit.
• Inputs vehicle speed signals to the TPMS control module via CAN
communication.
• If the TPMS control module detects abnormal air pressure, the light is
illuminated to alert the driver.
• If any abnormality is detected in the system, the light is flashed to inform the
driver.
• If the TPMS control module detects abnormal air pressure, the buzzer is
sounded to alert the driver.
Function
WHEEL UNIT
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