Resetting the TPMS forces re-initialization. It sets the current pressure as the new nominal pressure for each tire. The lowest pressure it'll allow is 23.2 psi. So you're responsible for filling up the tire to the correct cold pressure and then re-initializing the system. Then you have to drive for 12 minutes over ~20 mph for the sensors to configure themselves.
Quote:
An initialisation of the tyre pressure control must be performed in the following cases:
The tyre pressure is changed.
A wheel exchange is carried out. The exchanged wheels must be equipped with the correct wheel electronics systems.
Axle-wise wheel exchange on the vehicle.
Diagnosis instruction
During the initialisation process, the existing inflation pressure is transferred as a specification for the nominal pressure.
The driver is personally responsible for setting the correct inflation pressures on cold tyres in accordance with the operating instructions. Depending on the series,various operating points are possible for the initialisation process:
operation of the central information display (CID)
operation of the instrument panel via the drop arm
operation of the radio
operation by button
This must be done with the vehicle at a standstill and with terminal 15 ON. The RDC acknowledges the initialisation process with a display on the instrument panel, radio or CID. These Check Control messages remain visible until the initialisation process has terminated. At the end of the initialisation process, all warning lights go out.
The RDC control unit checks the plausibility of the nominal value before adopting it (minimum pressure). Any initialisation is only possible if the inflation pressure in all wheels is at least 1.6 bar. If the tyre pressure of one wheel falls below this limit, a Check Control message is issued immediately.
Remedy: Set inflation pressures to correct values then repeat the initialisation process. If the initialisation process is forgotten after wheel exchange or after replacing the wheel electronics, the driver is asked to perform the initialisation process on vehicles equipped with an iDrive ('intelligent Drive') control centre.
Internal procedure after an initialisation has been triggered (reset):
Recognition of the fitted wheel electronics systems
Identifying the position of the wheel electronics systems
Plausibility check by checking the nominal pressures against the minimum pressures
Adoption of the specified pressures as nominal pressures
The tyre pressure increases by 0.1 bar per 10 °C increase in temperature. If the temperature-evaluated limit values are not reached, the Tyre Pressure Monitor issues a Check Control message.
In the initialisation there are substitute values up until the complete allocation of the wheels (e.g. 6.4 bar; 127 °Celsius).
To finalise the assignment of wheels successfully, the vehicle must be driven for at least 12 minutes at a speed in excess of 30 km/h.
National-market versions
USA, Canada, Europe
Transmission frequency of the system: 433 MHz
Reception frequency of the system: 125 kHz (only for Development and the manufacturing plants)
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