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

GF40.15-P-0001GZ Tire pressure monitor function
- with CODE (475) Tire pressure monitor (Siemens)

Component Identification:

General
The tire pressure monitoring system (TPM) permanently monitors the tire inflation pressures. 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 (N88) via an HF transmission path.

The tire pressure monitoring system assists the driver with monitoring the correct tire inflation pressure and thus serves the purpose of active safety. It fulfills the requirements of the NHTSA (National Highway Traffic Safety Administration).

Via the multifunction display (A1p13) in the instrument cluster (A1) the driver is informed about the current tire inflation pressure or about the necessary corrections to the tire inflation pressure and about flat tires.

Advantages
Safety:
^ "Blowouts" due to excessive flexing, caused by driving too fast with insufficient tire pressure, are avoided.
^ The driver is requested to check the tire inflation pressure.
^ A timely warning ensues in the event of a rapid pressure drop (greater than 0.25 bar/min).

Sudden depressurization cannot be detected due to the system.

Comfort:
^ Regular checking of tire inflation pressure is simplified.

The tire pressure monitor system does not relieve the driver of a regular manual check of the tire inflation pressure (at least every 14 days). In the process the correct tire inflation pressure must be adjusted by means of the table in the fuel filler flap. The tire pressure monitor system does not warn against an incorrectly adjusted tire inflation pressure.

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

System components
The tire pressure monitor system consists of the following components:
^ Central TPM [RDK] antenna
^ Left rear TPM [RDK] wheel antenna
^ Right rear TPM [RDK] wheel 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
^ Buttons + and - for setting specific functions and volume control

Function
The wheel sensor is mounted on the metal valve (not visible from outside) and measures the air pressure and temperature inside the tire.

The data transmitted by the wheel sensors are received by wheel specific antennas. The TPM [RDK] control unit (N88) evaluates this data and determines the position of the transmitter from the field strengths measured at the wheel antennas. This ensures that the data can be correctly matched to the relevant wheel.

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.

Messages relevant to operation
^ Rapid pressure drop (greater than 0.25 bar/min);
^ Dropping below a warning limit (the adjusted specified pressure is dropped below by more than 0.25 bar);
^ Request for reactivation of system;
^ Rejection of system activation because of implausible pressure values.

Messages relevant to the function:
^ Influence of an external interference transmitter does not allow the tire inflation pressures to be checked.
^ Function failure of the tire pressure monitor system.