Detecting Seeping Pressure Loss, Function - GF40.15-D-2001HH
MODEL 906
Seeping pressure loss
Every tire loses air by diffusion over the course of time. It is advisable to check the tire pressures every 2 weeks.
The tire pressure monitor system supports this routine check and displays a warning message, when creeping pressure loss is given.
Soft-warning
The "soft warning" operating mode is characterized by a minimum tire pressure at which the vehicle can continue to be driven safely. At the end of the journey, the driver receives a message on the display (A1p1) of the instrument cluster (A1) requesting that the tire inflation pressure be corrected at the next opportunity.
If circuit 15 is "OFF", the message is shown on the display of the instrument cluster for 30 s. A "soft warning" is triggered when the temperature-compensated tire inflation pressure drops by more than 0.25 bar compared to the filling pressure.
With the "soft warning" operating condition, the tire is generally not specified as all tire pressures must normally be corrected.
Hard warning
The "hard warning" operating condition is characterized by a minimum tire pressure at which driving safety is no longer fully guaranteed.
While driving the vehicle, the driver receives a message on the display of the instrument cluster requesting that the tires be checked. The driver is asked to stop the vehicle and check the condition of the tires or to correct the tire pressure. It is the driver's responsibility to decide whether to continue the journey at low speed as far as the nearest workshop or whether an on-the-spot repair is necessary (use of TIREFIT or replacement of wheel).
A "hard warning" is triggered if one of the following conditions is fulfilled:
- The tire pressure drops below 1.9 bar
- The tire pressure drops by 20 % compared to the filling pressure (maximum 0.5 bar)
The RDK indicator lamp (A1e29) in the instrument cluster is actuated parallel to the "hard warning". It goes out again after reactivation of the Tire pressure monitor (TPM) system and after it has been determined that for a conducted pressure correction was set at least to the previously set pressure (minus 0.15 bar tolerance, up to 31.12.2010 or minus 0.2 bar tolerance, as of 1.1.2011).
The "hard warning" is only displayed as long as circuit 15 is ON. When circuit 15 is set to ON again, the warning lamp is immediately actuated and the warning reappears after the vehicle has been driven for approx. 5 minutes.
With the operating condition "hard warning", the tire concerned is highlighted on the display of the instrument cluster.
| Component description for tire pressure monitor control unit | GF40.15-D-5124H |
| Wheel antenna, component description | GF40.15-D-5125HH |
| Wheel sensor, component description | GF40.15-D-5126H |