Comfort Access System

Comfort Access Sub-Bus (K-TAGE)
The Comfort Access Subbus is a single-wire bus and it connects the following components of the access and driver authorization system:
- the Comfort Access control module
- the outside door handle electronics in all four doors
- the Car Access control module (CAS) as bus master

Check of the Comfort Access Subbus
The status of the outside door handles is transferred across the Comfort Access Subbus to the CAS and Comfort Access control module. In the diagnosis system, it is possible to read the status of the outside door handles in the control-module functions of the two control modules. If a readout is only possible at one control module, the bus connection of the defective control module must be checked. If it is not possible to read out the status of an outside door handle, the bus line in the corresponding door or in this area must be checked. The CAS is the simultaneously the gateway between the data buses K-CAN SYSTEM and K-CAN PERIPHERIE. For diagnosis of the Comfort Access control module, is must be borne in mind that the CAS has to shift the diagnosis commands to the Comfort Access control module on the K-CAN Peripherie bus. Without function of the CAS or K-CAN System and K-CAN Peripherie buses, no diagnosis on the Comfort Access control module is possible. A bus interruption between CAS and the Comfort Access subbus can also lead to malfunctions in the remaining bus system. The terminating resistor of 1 kOhm of the bus is located in the CAS and is necessary for the reliable function.