Detect seeping pressure loss, function - GF40.15-P-2001TRU

MODEL 211 

with CODE (470) Tire pressure monitor (base) 

with CODE (494) USA version 

Function 

Each tire looses air in the course of time due to diffusion. As a comfort function the driver receives in good time information on the due correction of his tire pressure from the TPM system. The warning takes place immediately after the journey's end.

Temperature compensation 

A temperature increase always leads to a pressure increase in the wheel. To detect pressure changes the measured pressures are temperature-compensated in the TPM [RDK] control unit (N88). It is converted to a compensated pressure. Rapid temperature changes must not lead to erroneous warnings.

Soft warning 

In the event of a pressure loss of 0.25 bar compared with the stored filling pressure the warning takes place in a temperature-compensated manner. The warning threshold is limited upwards to 0.2 bar below the filling pressure.

Cancellation of the warning: 

• The warning threshold is no longer dropped below
• Filling detection was successful
• Manual reactivation of the system carried out

Checking the warning condition while driving 

If the warning threshold is dropped below for a time of 12 minutes, a warning signal is stored in the memory of the TPM [RDK] control unit and is displayed in the instrument cluster (A1) when the ignition is "OFF".

Hard warning 

While driving the hard warning informs the driver of a significant pressure loss which is relevant to safety. The warning meets the requirements of the USA legislation.

Parameters for the hard warning: 

• The warning takes place at a pressure loss of 20 % or 0.5 bar compared with the stored filling pressure.
• The warning threshold is limited downwards to the minimum pressure (1.5 bar).
• Temperature compensation with hot tires is limited to a temperature of 40°C above the ambient temperature. The warning threshold remains constant.
• The warning threshold is limited upwards to 0.2 bar below the filling pressure.

The warning is suppressed during filling detection.

The tire pressure monitor warning lamp (A1e66) in the instrument cluster is actuated in parallel with the "hard warning". It disappears only after the TPM system is reactivated.

Cancellation of the warning: 

With an ignition restart after a hard warning the tire pressure monitor warning lamp is actuated first. The warning is canceled by successful filling detection or a manual reactivation.

Tire pressure monitor control unit, component description	GF40.15-P-5124TR
Wheel sensor, component description	GF40.15-P-5126TR
System activation button, component description	GF40.15-P-5127TR
Central TPM [RDK] antenna, component description	GF40.15-P-5129TRU