Communication Line & System Constraint

The exchange of the immobilization status between ECM and BCM is made on the current K-line. The BCM is inserted on the K-line between the ECM and the diagnosis connector, and manages an internal switch that opens the K-line during the exchange of status after the reset of ECM, or Key Off/On transient under power latch, as soon as the fast wake up pattern from the ECM is recognized. This configuration keeps the K-line accessible by the tool at the diagnosis connector. The only constraint is during the immobilizer communication where BCM and ECM cannot be addressed by the tool for diagnosis.