Tire Monitoring System: Description and Operation

TIRE AND WHEEL: TIRE PRESSURE WARNING SYSTEM:

SYSTEM DIAGRAM




HINT: The tire pressure warning valve and transmitter sends information on the temperature inside the tire, the ID, and the tire pressure.

SYSTEM DESCRIPTION

1. DESCRIPTION OF SYSTEM
(a) Each tire pressure warning valve and transmitter is equipped with a tire pressure sensor and transmitter and is installed in each tire wheel. The sensor measures the tire pressure. The measured value and transmitter ID are transmitted to the tire pressure warning antenna and receiver on the body as radio waves and then sent to the tire pressure warning ECU from the tire pressure warning antenna and receiver. If the transmitter ID has already been registered, the ECU compares the measured tire pressure value with the standard value. When the value is less than the standard value registered in the tire pressure warning ECU, the warning light on the combination meter turns on.
When the air pressure settings of the tires are different, the tire pressure warning reset switch is used to initialize the system according to the type of tires.





2. INITIAL CHECK





(a) After the ignition switch is turned ON, the tire pressure warning light turns on for 3 seconds and then turns off.
HINT: If the warning light does not turn on for 3 seconds, troubleshoot the pressure warning light circuit.





3. WHEN TIRE PRESSURE WARNING LIGHT IS LIT
(a) When the tire pressure warning light does not go off, or when it turns on during driving, check the tire pressure. If the tire pressure warning light turns on within several hours of adjusting the tire pressure, the tire may have a slow air leak.
(b) The system will not operate under the following conditions:
HINT: When the problem is resolved, the system will operate properly.
- Tires without a tire pressure warning valve and transmitter are used.
- When a tire pressure warning valve and transmitter ID is not registered in the ECU.
- The tire pressure is abnormally high (absolute pressure: 600 kPa (6.1 kgf/cm2, 87 psi) or higher; relative pressure: 500 kPa (5.1 kgf/cm2, 73 psi) or higher).
- The battery of the tire pressure warning valve and transmitter has been depleted (battery life: 10 years).

(c) The system may not operate under the following conditions:
HINT: When the problem is resolved, the system will operate properly.
- Facilities or devices that use similar radio frequencies are located in the vicinity of the vehicle.
- A radio device of similar frequency is used in the vehicle.
- A type of film that affects radio waves is attached to the windows.
- A large amount of snow or ice is stuck to the vehicle, especially onto the wheels and around the wheel houses.
- If any wheels other than the specified ones are used, the system may not function properly because interference may prevent the radio waves from being correctly transmitted from the tire pressure warning valve and transmitter.
- Tire chains are used.
- A large metallic object which can interfere with signal reception is put in the luggage room.

(d) If a tire pressure warning valve and transmitter is removed from a wheel, replace the grommet.
(e) After removing and installing the ECU or a sensor, check for a diagnostic trouble code and verify that it is a normal code.
4. FUNCTION OF COMPONENTS






5. TIRE PRESSURE WARNING RESET SWITCH

- By operating the tire pressure warning reset switch, the tire pressure warning ECU can be set to issue a warning at an inflation pressure that corresponds to the type of tires. Therefore, the dealer must set the warning threshold to the proper value in order to comply with local regulations.
- Operate the tire pressure warning reset switch only after the inflation pressures of all tires have been adjusted on the vehicle.
- To initialize the system, press and hold the tire pressure warning reset switch for 3 seconds or longer with the ignition switch in the ON position. When the system receives the initialization signal, the warning light blinks 3 times (1 second on, 1 second off).
- During initialization, the tire pressure warning valve and transmitters measure the inflation pressure of the tires, and register the signals that are transmitted into the tire pressure warning ECU at a frequency of once per minute. The initialization process is completed when signals from all tires have been received.