【TPMS Sensor : Wheel Electronic (WE) Sensor
Unit】
Each vehicle wheel is
fitted with a Wheel Electronic (WE) sensor unit attached to the valve on
the inside of the wheel. The WE unit is powered with a self-contained
battery utilizing a high temperature rated CR (Manganese Dioxide Lithium)
chemistry. The operating voltage range for the WE module is 2.2 Vdc to 3.6
Vdc, and the operating temperature range is -40 °F to 257 °F(-40 °C ~125
°C). The WE measures tire pressure, temperature, and acceleration
periodically. The pressure, temperature, and acceleration information is
converted to digital form within the MCU inside the WE
sensor.
The WE sensor is
equipped with a Radio Frequency (RF) transmitter circuit which is used to
periodically broadcast information from inside the tire. All WE sensor
units operate on the same RF channel frequency, and each broadcast message
includes pressure and temperature data, a unique ID code, operating state
data, status information, and digital error-detection data.
The pressure measured by
the WE sensor is an absolute pressure value. The pressure measurement
range is 100 kPa (14.5 psi) to 450 kPa (65.27 psi). The acceleration data
is used within the WE sensor to determine whether the vehicle is moving or
stationary. The acceleration status is the decision maker within the WE
module that determines if the tire is moving or stationary. This
measurement is used within the WE module to enable different operating
modes depending on the status of the acceleration value. Over the fully
specified operating temperature range, if the acceleration measurement is
greater than or equal to 20G, the WE module assumes the tire is
moving.
The basic operation of
the L/L WE sensor is to transmit 3 frames every 3 minutes in both
stationary and rolling modes.
This DTC indicates that
an unmonitored tire is detected.
Item
|
Detecting
Condition
|
Possible cause
|
DTC
strategy
|
|
| •
|
The tire with TPM sensor not fitted at
hub. | |
Enable
conditions
|
| •
|
Vehicle speed is at Normal Speed (>45
km/h (28 mph)). |
| •
|
Speed sensor input is not
faulted. | |
Threshold
value
|
| •
|
1 or more WE sensors transmit 3
consecutive RF signal indicating
stationary. | |
Diagnosis
time
|
|
| 1. |
Connect TPMS exciter or scantool and select
"Diagnostic Trouble Codes(DTCs)"
mode |
| 4. |
Operate the vehicle within DTC Detecting
Condition in General Information. (Start and drive vehicle in gear
and maintain vehicle speed at or above 45km/h.
(28mph)) |
| 5. |
Execute "Diagnostic Trouble Codes(DTCs)"
mode. |
| 6. |
Is 'C1301' present ?
|
|
▶ Find the
tire with TPM sensor which is stationary when the vehicle is
moving.
▶ If there isn't stationary
tire in the car, replace TPMS receiver and then go to
"Verification of Vehicle Repair" procedure.
|
|
|
▶ Fault is
intermittent. It has been repaired and TPMS receiver module
memory is not cleared yet.
▶ Go to
"Verification of vehicle Repair"
procedure.
|
|
| Verification of Vehicle
Repair |
After a repair, it is
essential to verify that the fault has been corrected.
| 1. |
Connect TPMS exciter or scantool and select
"Diagnostic Trouble Codes(DTCs)"
mode |
| 2. |
Using a TPMS exciter or scantool, Clear
DTC. |
| 3. |
Operate the vehicle within DTC Enable
conditions in General information. |
| 4. |
Are any DTCs present ?
|
|
▶ Go to the
applicable troubleshooting procedure.
|
|
|
▶ System
performing to specification at this
time.
|
|
