DTC P1694 Ems Message Error: General Description

The vehicle immobilizer system consists of the EMS, the SMARTRA and ignition keys with built-in transponder. The EMS carries out the check of ignition key by special encryption algorithm with SMARTRA and Transponder. When IGN On, the EMS executes the key Authentication after SMARTRA authentication. The Engine can be started in case of the success in SMARTRA and key authentication.

The EMS and the SMARTRA communicate by dedicated line. During this communication of EMS and SMARTRA the K line of EMS cannot be used for communication. The EMS controls the communication either to SMARTRA or to other devices (e.g. service tester) on K line by switching of a multiplexer and specific communication procedures. The multiplexer is a part of EMS H/W.