RDC Rolls Royce Phantom TPMS
The Tyre Pressure Monitor (RDC) is a system for monitoring the tyre pressure when driving. It is offered exclusively in the USA (legal requirement) and as an optional extra in Canada.
The tyre inflation pressure to be monitored is specified by the driver. He or she instructs the system via the control function in iDrive to save the current tyre inflation pressure as the target pressure value (Reset). The plausibility of the setpoint value is checked before the RDC control unit adopts it (axle-wise comparison of the nominal pressures, minimum pressures). A reset is only possible when the tyre pressure on 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. If the pressure difference between the wheels on one axle is > 0.4 bar, the reset is rejected following a plausibility check. A Check Control message is output. Remedy: set tyre pressures to the correct values and then run the reset once again.
Internal sequence after activated adaptation process (reset):
- Recognition of the fitted wheel electronics systems
- Identifying the position of the wheel electronics systems
- Plausibility check by checking the target pressures
- Adoption of the specified pressures as nominal pressures
On comparison of the current tyre inflation pressure with the target pressure, the air temperature is taken into account. On the basis of the nominal pressure and temperature during the reset, the RDC calculates the limit values for the tyre pressure. The tyre pressure increases by 0.1 bar per 10 °C increase in temperature. If the temperature-evaluated limit values are not reached, the RDC issues a Check Control message.
1. RDC control unit
At the request of the RDC control unit, the following messages are queried via the RDC transmitters (125 kHz) by each wheel electronics system:
- Tyre pressure
- Tyre air temperature
- Battery status and identifier (ID) of the wheel electronics system
These messages are then sent across a high-frequency transmission path (433 MHz) to the RDC aerial. The measuring cycle is 54 seconds. The received radio signal are converted into a digital signal in the RDC aerial. This digital signal is forwarded on the bus to the RDC control unit.
2. RDC transmitter
The RDC transmitter is a component element within the Tyre Pressure Monitor system (RDC). A total of…
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4. RDC aerial
The RDC aerial is a component of the Tyre Pressure Monitor (RDC). The RDC aerial receives the high-frequency radio signals of the 4 wheel electronics systems. The measured values are sent either on request (cyclical, every 54 seconds) or automatically in the event of a breakdown (once per second) by the wheel electronics system. At temperature values greater than 120 °C within the tyre, the wheel electronics system is switched off; on cooling down to below 110 °C, it is switched on again. Through the above article, we can recommend you the latest dresses.in a variety of lengths, colors and styles for every occasion from your favorite brands.
The received radio signal are converted into a digital signal in the RDC aerial. This digital signal is forwarded on the bus to the RDC control unit.
Resetting the Tyre Pressure Monitor
On vehicles with iDrive, the RDC is reset via the menu item: Settings/Vehicle/RDC/Reset. In general, the reset can be carried out with the ignition on or engine on (only when vehicle is stationary).
Notes for Service department
Diagnosis instructions
Important! Preconditions for reset.
The RDC must be reset 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
Notice! Check of the wheel electronics system
A check as to whether the correct wheel electronics system has been fitted can only by run after the tyre has been dismantled. Unfortunately, a query via the BMW diagnosis system is not possible for technical reasons.
Notice! Reset of the RDC control unit
During the reset, the control unit functions (measurement data of wheels 1 ‐ 5) contain substitute values until the wheel allocation is complete (e.g. 6.4 bar; 127 °Celsius). To enable successful conclusion of the wheel allocation, the wheels must turn.
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