System Description

SYSTEM DIAGRAM





SYSTEM DESCRIPTION
1. DESCRIPTION OF SYSTEM
(a) A tire pressure warning valve and transmitter is equipped with a tire pressure sensor and a transmitter and is installed in each tire wheel assembly. The sensor measures the tire pressure. The measured value and transmitter ID are transmitted to the tire pressure warning ECU on the vehicle body as radio waves. The ECU compares the measured air 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.
^ The tire pressure warning reset switch addresses the differences in the air pressure settings by the type of tires, and the differences in pressure between the front and rear tires.
^ Tire pressure warning system transmitters for aluminum wheels have different bending angles at the tire pressure warning valve and transmitter. These transmitters are not interchangeable with other wheels.





2. WHEN TIRE PRESSURE WARNING LIGHT IS LIT
(a) When the tire pressure warning light does not turn off, or when it turns on during driving, check tire pressure. If the tire pressure warning light turns on within several hours after adjusting the tire pressure, the tire may have a slow air leak. If the tire pressure warning light turns on even after adjusting the tire pressure, selection of the tire pressure warning switch "MAIN" / "2nd" may be incorrect.
(b) Under the following conditions, the system may not function properly:
^ Areas, facilities or devices that use similar radio frequencies are located in the vicinity of the vehicle.
^ Devices using similar radio frequencies are used in the vehicle.
^ Large amounts snow or ice are stuck to the vehicle, especially on the wheels and around the wheel houses.
^ The battery of the transmitter is depleted.
^ Tires and wheels without tire pressure warning valve and transmitters are used.
^ Snow tires and tire chains are used.
^ The registered set of the tires and wheels does not correspond to the selection of the tire pressure warning select switch.
^ If wheels other than the specified ones are used, the system may not function properly because different radio waves are transmitted from the tire pressure warning valve and transmitter.
^ Depending on the tire type, the tire pressure warning valve and transmitter may not function properly even though the specified wheels are used.
^ The system may not function properly unless it is initialized with the tire pressures at the specified values.
(c) The average useful life of the grommet of the tire pressure warning valve and transmitter is approximately 5 years, at which time it must be replaced.
If air is leaking from the tire but the tire is less than 5 years old and there is no problem with grommets, retighten the valve nut.
(d) After removing and installing the ECU or a sensor, check the DTC to check that the normal code is output.
3. FUNCTION OF COMPONENTS





4. 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 the local regulations.
^ Operate the tire pressure warning reset switch only after the inflation pressures of 4 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 power switch ON (IG). After the system has been initialized, the warning light blinks 3 times (1 second on, 1 second off).
^ During initialization, the tire pressure warning valve and transmitter measures the inflation pressure of the tires, and registers the signals that are transmitted into the tire pressure warning ECU at a frequency of one per minute. The initialization process is completed when the signals from the 4 tires have been received.
^ Initialization is usually completed in 2 or 3 minutes.
5. TIRE PRESSURE WARNING SELECT SWITCH
^ This switch is installed at the base of the instrument panel on the driver seat side.
^ The tire pressure warning ECU can be used to register 2 sets of transmitter IDs, and can select one or the other using the tire pressure warning select switch. Consequently, there is no need to log the ID again each time a tire is changed.
^ Make sure ID registration is performed by your car dealer.