MoDiC - Control Module Communication

MoDiC - Control Module Communication
The MoDiC communicates with the vehicle control modules through the 20 pin diagnostic connector. The wiring circuits that connect the control modules in the vehicle is called the "diagnostic link".


The main circuits are called "RXD" and "TXD". These two circuits are connected to all control modules in the vehicle that are capable of communicating with the MoDiC and DIS for the purpose of diagnosis and coding.
- RXD initiates the communication with the control module. It is often referred to as the "Ring" of a telephone to the control module.
- TXD is the "Transmit" line between the test equipment and the control module.
- Pin 18 of the 20 pin diagnostic connector is the "DME Code" link. This is unique to DME. It is a single wire communication line between the DME control module and the MoDiC. The DME Code link transfers variant coding data or programming data to the specific DME control module. Reference SI XX XX XX (XXXX) for information regarding pin 18 if problems occur when variant encoding M1.3 control modules.
- TXD II is a single wire link added to BMW control systems for federal compliance with OBD II. This new link is required on all 96 model year vehicles for aftermarket scan tool communications with driveline control modules (DME, AGS, EML).