PRELCI to LCI RDC Retrofit (1%)

[SaNGRia]

Hello everyone,
I recently acquired a new wheel and tire set. In an effort to ensure compatibility, I sourced the TPMS sensors based on the vehicle's production date (which proved to be the wrong approach). These sensors are incompatible with the existing TPMS control system, resulting in the RDC Reset and Initialization procedures failing and the system being permanently inactivated.

My current diagnostics suggest the following:

The issue is not sensor frequency, as my previous sensors operated on the required frequency.

The issue is a communication protocol mismatch between the newly installed TPMS sensors and the vehicle's current RDC Control Unit. The sensors are operating on the LCI (Life Cycle Impulse) protocol, while the current RDC Control Unit is expecting the pre-LCI protocol.

My Solution :

My vehicle is a post-LCI conversion, having already had all necessary modules successfully retrofitted. Therefore, the most logical and permanent solution is to address the RDC system architecture itself.

I plan to retrofit the LCI RDC Control Unit (Module) to resolve this protocol incompatibility, eliminating the need for a costly and time-consuming physical sensor swap.

Technical Request
I am currently finalizing the specifics of the retrofit:

I am confirming the correct LCI RDC Control Unit part number for my chassis.
Then will code the module and thinking it will recognize the TPMS. But before hand i need to really pinpoint couple things. Here is how BMW RDC system works :

The Tyre Pressure Monitor (TPM) is a system for monitoring the tyre inflation pressure while the vehicle is being driven. For this purpose, the tyre pressure and the tyre air temperature are measured at certain intervals on request by the RDC control unit and telemetrically transmitted to the RDC aerial via a high-frequency transmission path. The RDC aerial forwards the signals back across the bus to the RDC control unit. The control unit evaluates the received data. It then forwards the information to the driver if necessary. The driver is thus informed of a necessary correction of the tyre pressure or a puncture that might have occurred.
Brief component description
The following components for RDC are described:

RDC aerial
The TPM aerial is generally located on the underbody. Depending on the series, the position can be in the front section (cross -member of A-pillar) or in the central area of the underbody.

RDC transmitters
The 4 RDC transmitters are fitted under the wheel arch trim in the wheelhouses. The TPM transmitters send the requests from the control unit to the wheel electronics systems. This achieves bidirectional communication.

Wheel electronics systems in the road wheels and in the spare wheel
The wheel electronics systems are fitted in the wheel drop centre. Together with the filling valve, they form a compact unit and are fitted in the same way as a screw valve in the rim. The wheel electronics includes:

Pressure sensor
Temperature sensor
Lateral acceleration sensor
Battery
Transceiver aerial
The wheel electronics system is activated on initial fill of the tyre. The measured values are transmitted by the wheel electronics from the tyre to the RDC aerial either on request or cyclically (every 3 seconds). This cycle is temporarily shortened if a certain pressure change is detected. The wheel electronics unit responds to temperatures exceeding 120°C within the tyre with automatic deactivation, and resumes operation once the temperature cools to below 110°C. Transmission rate normal: 54 s; Transmission rate increased: 0.8 s; Battery life: approx. 10 years.

RDC control unit
The RDC control unit evaluates the pressure and temperature values transmitted from the individual tyres. The driver is informed if necessary by a Check Control message on the instrument cluster. This message is accompanied where applicable by a supplementary message on the control display.

Overall function
The TPM monitors the tyre pressure whilst the vehicle is being driven. The tyre pressure to be monitored is specified by the driver. Using the control function in the control centre or the TPM button, the driver instructs the system to adopt the current tyre pressure as setpoint pressure (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 valid for the current air temperature. The tyre pressure increases by 0.1 bar per 10 °C increase in temperature. If the temperature-evaluated values are not reached, the RDC issues a Check Control message.

So there is 3 hardware on this system. First one is the RDC Control Module which is the white box (I checked the coding data on that cant see anything beside each section can be coded either EU or US nothing like protocol specific)

Second piece is the RDC Aerial which reads the 433MHz and sends to RDC Module.

Third one is the TPMS trasmitter which is located on each wheel arch per TPMS.

So if PRELCI and LCI running on 433MHz then no need to replaced the RDC Aerial. Same goes to TPMS transmitters, if they are getting the same frequency transmitter should able to read the psi and temp without an issue. My observatrion is that control module is the one cant communicate with the data is sent from Aerial. So i need some opinions here before i pull the triggers for parts.

(Note i have done some research and did not see anyone who actually done retrofit on prelci to lci for TPMS)