1. Tire pressure monitoring system overview
1. Tire air pressure monitoring system overview
The TPMS (Tire Pressure Monitoring System) is a system that informs the driver of a decrease in tire air pressure. The TPMS is comprised of the wireless access module, tire air pressure sensors, TPMS load selector switch, TPMS warning light, TPMS loading indicator light, etc. The wireless access module receives information wirelessly from the tire air pressure sensor installed to each tire. The wireless access module also receives the barometric pressure information from the ECM and the ambient temperature information from the instrument panel cluster, and corrects the tire pressure. The wireless access module starts monitoring each tire air pressure when the vehicle speed becomes 30 km/h {19 mph} or more. If the tire air pressure decreases to the specified value or less, the wireless access module illuminates the TPMS warning light by sending a light drive request to the instrument panel cluster via the CAN communication circuit.
In addition, the TPMS includes the automatic registration of each tire air pressure sensor ID, automatic location, change of the tire air pressure specified value with the TPMS load selector switch when loaded/unloaded, and the tire air refill assist function activated when adjusting the tire air pressure.
2. Function of tire pressure monitoring system
The tire air pressure sensor transmits the information when the vehicle speed becomes 30 km/h (19 mph) or more. This information includes the sensor ID, tire air pressure, tire temperature, wheel rotation, and sensor status. The wireless access module receives information wirelessly from the tire air pressure sensor.
The TPMS (Tire Pressure Monitoring System) has the following functions.
- Tire air pressure sensor automatic registration and automatic location
- Tire air pressure monitoring and warning functions
- Load/unload switching function
- Tire Air Refill Assist Function
1. Tire air pressure sensor automatic registration and automatic location
- Tire air pressure sensor automatic registration
The wireless access module determines whether the tire air pressure sensor is installed based on the frequency of radio waves transmitted from the tire air pressure sensor installed to each running tire, and automatically registers the ID of each tire air pressure sensor. The tire air pressure sensor has its own ID. When the vehicle is driven at a vehicle speed of 40 km/h {25 mph} or more for a predetermined length of time, the sensor ID automatic registration is complete. During the automatic registration of the sensor ID, the wireless access module displays "----" on the MID. If the registration is not complete, the DTC is set.
Note
- The tire air pressure sensors are installed to all the tires including a spare tire. However, the spare tire does not emit radio waves because it does not rotate.
- Automatic location
After the tire air pressure sensor ID is automatically registered, the wireless access module determines the position of each sensor. When the vehicle is driven at a vehicle speed of 40 km/h {25 mph} or more for a predetermined length of time, the automatic location is complete. During the automatic location, the wireless access module displays "----" on the MID. If the automatic location is not complete, the DTC is set. When the vehicle is moving forward, the wireless access module identifies the position of each tire air pressure sensor based on the wheel speed information from the ABS. The wireless access module determines whether the vehicle is moving forward or backward based on the shift status received from the BCM. After the automatic location is completed, the wireless access module outputs the tire air pressure of each tire air pressure sensor to the CAN and displays it on the MID.
Note
- When the automatic location is not determined, each tire air pressure is displayed at the position estimated by the wireless access module.
- The tire air pressure sensor automatic registration and automatic location are normally complete in 5 to 10 minutes.
2. Tire air pressure monitoring and warning functions
The wireless access module starts monitoring each tire air pressure when the vehicle speed becomes 30 km/h {19 mph} or more. The wireless access module receives the barometric pressure information from the ECM and the ambient temperature information from the instrument panel cluster, and corrects the tire air pressure. If the tire air pressure decreases to the specified value or less, the wireless access module illuminates the TPMS warning light. After adjusting the tire air pressure, the wireless access module turns OFF the TPMS warning light.
For models with MID, after completing the sensor automatic registration and automatic location, each tire air pressure can be checked on the MID. If the tire air pressure is normal, the tire is displayed in gray. When the tire air pressure is lower than the specified value, the applicable tire is displayed in yellow. If the tire air pressure is significantly lower than the specified value, the applicable tire is displayed in red.
3. Load/unload switching function
By pressing the TPMS load selector switch, the driver can switch the tire air pressure specified value when loaded/unloaded. The TPMS loading indicator light illuminates in the instrument panel cluster when the tire air pressure specified value is set as the specified value for the loaded vehicle. The TPMS warning light flashes for 6 seconds when the tire air pressure specified value is switched. For vehicles equipped with tires of the following sizes, it is necessary to switch the tire air pressure specified value when cargo is loaded/unloaded on the rear body.
- 195R15C
- 205R16C
- 215/70R15C
- 255/65R17
- 265/60R18
Note
- The following are the specified values for each tire air pressure.
| Vehicle model |
Tire size |
Tire air pressure kPa (kgf/cm² / psi) |
||
| Front |
Rear |
|||
| Unloaded |
Loaded |
|||
| 2WD (Regular/Crew cab model) |
195R15C |
275 (2.75/40) |
275 (2.75/40) |
450 (4.50/65) |
| 215/70R15C |
225 (2.25/33) |
225 (2.25/33) |
375 (3.75/54) |
|
| 2WD High-Ride (Crew cab model) |
255/65R17 |
230 (2.30/33) |
230 (2.30/33) |
300 (3.00/43) |
| 265/60R18 |
230 (2.30/33) |
230 (2.30/33) |
300 (3.00/43) |
|
| 4WD (Regular cab model) |
205R16C |
Unloaded: 260 (2.60/38) Loaded: 300 (3.00/43) |
260 (2.60/38) |
450 (4.50/65) |
| 4WD (Extended/Crew cab model) |
255/65R17 |
230 (2.30/33) |
230 (2.30/33) |
300 (3.00/43) |
| 265/60R18 |
230 (2.30/33) |
230 (2.30/33) |
300 (3.00/43) |
|
TPMS loading indicator light
TPMS warning light
4. Tire air refill assist function
Note
- The tire air refill assist function is a function that can be used only for WAM (Hi-version) equipped models.
When the tire air refill assist function is activated, the wireless access module informs the driver with an external buzzer and a hazard light that the proper air pressure has reached to the upper or lower limit.
1) Tire air refill assist function operation start conditions
The tire air refill assist function starts operating when all of the following conditions are met.
- The ignition switch is turned ON.
- Vehicle speed 0 km/h
- The automatic location is complete.
Tire air refill assist function operation
| Situation |
Detail |
Buzzer [times] |
Hazard warning flasher [times] |
| TFA mode |
In TFA mode, the hazard light flashes at 2-second intervals. |
- |
- |
| Reached to proper air pressure |
The tire air pressure has reached to the proper air pressure. |
3 |
3 |
| Exceeded from proper air pressure or dropped from proper air pressure |
The tire air pressure exceeds the upper limit of the proper air pressure. |
7 |
7 |
| The tire air pressure is less than the lower limit of the proper air pressure. |
|||
| Reminder notification |
Excess/drop notification is continued while detecting air pressure fluctuations that deviate from the proper air pressure. |
7 |
7 |
Note
- When 20 seconds have passed since the change in the tire air pressure was stopped, the wireless access module ends the operation of tire air refill assist function.
- If another tire is filled with air during operation of the tire air refill assist function, the notification to the tire that was previously filled with air is prioritized.
3. Tire pressure monitoring system components
1. Tire air pressure sensor
The tire air pressure sensor is an integrated structure with the air valve and installed to each tire (Total 5 tires: 4 tires installed on the vehicle and 1 spare tire). The tire air pressure sensor has its own ID. The tire air pressure sensor has a G sensor and is activated by the rotation of the tire. When the vehicle starts running, only the tire air pressure sensors installed on the running wheels send the tire air pressure and temperature data to the wireless access module through radio waves. The tire air pressure sensor installed on the spare tire is not activated, and therefore does not send data. When the vehicle speed becomes approximately 30 km/h {19 mph} or more, the wireless access module starts monitoring each tire air pressure based on the data received from the tire air pressure sensors.
Note
- A battery is built into the tire air pressure sensor. (The battery life is approximately 10 years for normal use.)
Since the battery cannot be replaced, the tire air pressure sensor unit needs to be replaced if the battery is drained.
Legend
- Tire air pressure sensor
- Air valve
2. TPMS load selector switch
The TPMS load selector switch is installed to the instrument panel on the driver side. Each tire air pressure specified value can be changed with the TPMS load selector switch.
RHD
Legend
- TPMS load selector switch
LHD
Legend
- TPMS load selector switch
3. TPMS warning light
The TPMS warning light is in the instrument panel cluster. The TPMS warning light illuminates or flashes under the following conditions.
1) The TPMS warning light illuminates.
- 3 seconds have passed since the ignition switch was turned ON.
- Compared to the specified value, the tire air pressure has decreased by a certain level or more.
2) The TPMS warning light flashes.
- The wireless access module performs the air pressure sensor registration.
- The wireless access module cannot recognize the air pressure sensor.
- The tire air pressure specified value is switched.
Note
- If a specific DTC is set, the TPMS warning light illuminates after flashing for 63 seconds.
TPMS warning light
4. TPMS loading indicator light
The TPMS loading indicator light is in the instrument panel cluster. The TPMS loading indicator light illuminates when the tire air pressure specified value is set as the specified value for the loaded vehicle.
TPMS loading indicator light
5. TPMS screen display (Models with MID)
For models with MID, the air pressure of each tire can be displayed on the MID screen. If the tire air pressure is normal, the tire color is displayed in gray. Tires with decreased tire air pressure are displayed in yellow, and tires with significantly decreased tire air pressure are displayed in red.
4. Tire pressure monitoring system component views
RHD (Hi-version)
Legend
- Wireless access module
RHD (Mid-version/Lo-version)
Legend
- Wireless access module
LHD (Hi-version)
Legend
- Wireless access module
LHD (Mid-version/Lo-version)
Legend
- Wireless access module
Legend
- Tire air pressure sensor
RHD
Legend
- TPMS load selector switch
LHD
Legend
- TPMS load selector switch
RHD
Legend
- Tire air pressure label
LHD
Legend
- Tire air pressure label
5. General circuit diagram
1. Wireless access module (Hi-version) general circuit diagram
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2. Wireless access module (Hi-version) appearance, connector pin layout diagram
| PIN No. |
Pin Function |
| 1 |
Battery power supply |
| 2 |
- |
| 3 |
IG1 relay control |
| 4 |
- |
| 5 |
IG2 relay control |
| 6 |
ACC relay control |
| 7 |
Starter relay control |
| 8 |
Clutch output signal (M/T) |
| 9 |
Engine start/stop button LED indicator (amber) |
| 10 |
Engine start/stop button LED indicator (green) |
| 11 |
Engine start/stop button illumination |
| 12 |
Clutch input signal (M/T) |
| 13 |
Vehicle speed signal |
| 14 |
Immobilizer coil (+) |
| 15 |
Immobilizer coil (-) |
| 16 |
- |
| 17 |
- |
| 18 |
- |
| 19 |
IG1 feedback signal |
| 20 |
- |
| 21 |
IG2 feedback signal |
| 22 |
ACC feedback signal |
| 23 |
- |
| 24 |
Parking switch signal (A/T) |
| 25 |
- |
| 26 |
Engine start/stop switch 1 signal |
| 27 |
Engine start/stop switch 2 signal |
| 28 |
P/N position switch signal (A/T) / Neutral switch signal (M/T) |
| 29 |
- |
| 30 |
Stoplight switch signal |
| 31 |
- |
| 32 |
Power ground |
| PIN No. |
Pin Function |
| 1 |
External antenna (+) (Driver door) |
| 2 |
- |
| 3 |
- |
| 4 |
- |
| 5 |
External antenna (+) (passenger door) |
| 6 |
- |
| 7 |
Center in-vehicle antenna (+) |
| 8 |
- |
| 9 |
- |
| 10 |
- |
| 11 |
- |
| 12 |
- |
| 13 |
- |
| 14 |
Steering lock inhibition |
| 15 |
External buzzer control |
| 16 |
Steering lock position signal |
| 17 |
Steering lock operating permission signal |
| 18 |
LIN communication |
| 19 |
CAN high signal |
| 20 |
CAN low signal |
| 21 |
External antenna (-) (Driver door) |
| 22 |
Request switch signal (Driver door) |
| 23 |
- |
| 24 |
Request switch signal (passenger door) |
| 25 |
External antenna (-) (passenger door) |
| 26 |
- |
| 27 |
Center in-vehicle antenna (-) |
| 28 |
- |
| 29 |
- |
| 30 |
- |
| 31 |
- |
| 32 |
- |
| 33 |
- |
| 34 |
- |
| 35 |
- |
| 36 |
- |
| 37 |
Key monitor warning light control |
| 38 |
TPMS load selector switch |
| 39 |
- |
| 40 |
Signal ground |
3. Wireless Access Module (Mid-version/Lo-version) general circuit diagram
4. Wireless Access Module (Mid-version/Lo-version) outline view, connector pin layout diagram
| PIN No. |
Pin Function |
| 1 |
- |
| 2 |
Immobilizer coil (+) |
| 3 |
Ignition switch signal |
| 4 |
Key reminder switch signal (Models with keyless entry system) |
| 5 |
CAN high signal |
| 6 |
Power ground |
| 7 |
Battery power supply |
| 8 |
Immobilizer coil (-) |
| 9 |
Key monitor warning light control |
| 10 |
TPMS load selector switch |
| 11 |
Signal ground |
| 12 |
CAN low signal |