GF40.15-P-0001SX Tire Pressure Monitor Function

GF40.15-P-0001SX Tire pressure monitor function
- with CODE (475) Tire pressure monitor (Siemens) [model 216.3, 221.1]
- with CODE (494) USA version [model 216.3]

Component Identification:

General
Tire pressure monitoring (TPM) serves the permanent monitoring of tire inflation pressure.

For this purpose, tire inflation pressure and tire temperature are measured in the tire at certain intervals and transmitted by telemetrics to the TPM [RDK] control unit via a HF transmission path.

The TPM system assists the driver in monitoring the correct tire inflation pressure and serves active safety.

Via the multifunction display (A1p13) in the instrument cluster the driver is informed about the current tire inflation pressure or about the necessary corrections to the tire inflation pressure and about flat tires.

The TPM increases safety by prevention:
^ A tire blowout, occasioned by excessive flexing and fast driving at air pressure that is too low, is prevented.
^ The driver is requested to check the tire inflation pressure.
^ A warning ensues in good time in the event of a rapid pressure drop (pressure drop more than 0.2 bar/min).
^ Regular checking of the tire inflation pressure is thus simplified.

A sudden tire pressure drop cannot be detected by the TPM system.

Working life and economy
Tire wear as well as fuel consumption are reduced by the correct tire air pressure.

The TPM system does not release the driver from a regular manual check of the tire inflation pressure (at least every 14 days). Here the table in the fuel filler flap should be drawn on to set the correct tire inflation pressure. The TPM system does not warn against an incorrectly adjusted tire inflation pressure.

The tire pressure monitor system consists of the following components:
^ Left front TPM [RDK] wheel antenna
^ Right front TPM [RDK] wheel antenna
^ Central TPM [RDK] antenna
^ Left front TPM [RDK] wheel sensor
^ Right front TPM [RDK] wheel sensor
^ Left rear TPM [RDK] wheel sensor
^ Right rear TPM [RDK] wheel sensor
^ TPM [RDK] control unit
^ System selection button
^ Scroll forward/back button
^ OK button (S110s6)

Function
The TPM wheel sensors are attached to the metal valves on the rims, are not visible from outside, and measure the air pressure in the tires and the tire temperatures.

While driving, information by wireless on the absolute pressure in the tire, the acceleration, the temperature at the front left, front right, rear left, rear right as well as an ID (individual serial number) is transmitted to identify the wheel.

The ID serves the purpose of detecting the wheels fitted to the vehicle and not of ascertaining the location (e.g. left front).

The signals are received by the central antenna and passed on to the TPM control unit via a discreet line. The left front TPM [RDK] wheel antenna and right front TPM [RDK] wheel antenna which are also fitted produce trigger pulses for position determination of the front wheels.

This allows wheel-specific pressures to be displayed. The position of the rear wheels is first detected when cornering by means of the steering angle and different wheel speed values. While driving the left front, right front, left rear and right rear wheel sensors transmit 3 data telegrams every 60 seconds.

The absolute pressure, wheel temperature, acceleration, the ID and status information on manufacturer, frequency, pressure range etc. are transmitted in these data telegrams. The measuring range of the TPM wheel sensor covers between 0 and 5.5 bar (relative pressure).

The TPM [RDK] control unit is permanently operational. Each time the interior CAN is woken up by "terminal 15 ON" the TPM [RDK] control unit carries out a re initialization and starts to transmit signals to the instrument cluster.

In the TPM [RDK] control unit the air pressure, set and activated by the driver, of each wheel is stored as the specified pressure to be monitored. The data evaluated by the TPM [RDK] control unit is displayed in the multifunction display of the instrument cluster in the form of messages relevant to function and operation.