Wheel sensor, component description - GF40.15-P-5126TR

MODEL 211 as of 1.6.05

with CODE (475) Tire pressure monitor (Siemens)

except CODE (494) USA version

except CODE (498) Japan version

MODEL 211 as of 1.7.05

with CODE (475) Tire pressure monitor (Siemens)

with CODE (494) USA version

with CODE (498) Japan version

MODEL 211

with CODE (470) Tire pressure monitor (base)

with CODE (494) USA version

Installation location

The TPM wheel sensors are firmly bolted onto the inside of the rim.

The TPM wheel sensors of the Siemens system are not compatible with the TPM wheel sensors of the Beru system.

Fig 1: Locating TPM Wheel Sensor

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Components

Fig 2: Identifying TPM Wheel Sensor Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Design of TPM wheel sensor

Together with the filling valve the TPM wheel sensor forms a compact unit and is installed into the rim like a screw-on valve. Modifications to the rims are not required.

The following components are located in the housing of the TPM wheel sensor:

Task

The TPM wheel sensors are sensors that transmit various data by radio signal. The following data is transmitted:

Absolute pressure
Temperature of the sensor
Radial acceleration of the sensor (acceleration is dependent on the wheel speed)
Pressure sensor
Temperature sensor
Transmitter
Acceleration sensor (radial acceleration)
Lithium battery for internal power supply
ID of the sensor

This data is received by the central antenna and evaluated by the TPM [RDK] control unit (N88). The TPM wheel sensors contain a battery for transmitting the signals with a service life of 10 years.

The respective TPM wheel sensor must be replaced in the event of a defect in the battery.

Function

Each TPM wheel sensor transmits a data report to the central TPM [RDK] antenna. An individual electronic identification number (ID) is deposited in each TPM wheel sensor. The TPM [RDK] control unit assigns the ID to the wheels fitted to the vehicle (after a learning phase). If an adequate spare wheel with TPM wheel sensor is fitted it is detected and managed after a few minutes' driving.

After a wheel change or after a TPM wheel sensor has been exchanged the new TPM sensor with new ID (e.g. after fitting the spare wheel) is detected as quickly as possible and is monitored as a new ID, even if the TPM [RDK] control unit is still receiving information from the previously used wheel identifier. Wheel identifiers received from other vehicles do not result in incorrect warnings.

The TPM wheel sensors are marked according to national version and transmit their data on different frequencies:

315 MHz: recognizable by the frequency indication and an unfilled square symbol
433 MHz: recognizable by the frequency indication and square symbol filled with gridlines

The TPM sensors transmit three data telegrams every 60 seconds when driving. These data packets transmit the absolute pressure, the wheel temperature, the acceleration, the ID and status information (manufacturer, frequency, pressure range etc.). The tire pressuring measuring range extends from 0 to 5.5 bar (relative pressure).