The PCM/ECM and the SMARTRA communicate by dedicated line. During this communication of PCM/ECM and SMARTRA, the K line of PCM/ECM cannot be used for communication. The PCM/ECM controls the communication either to SMARTRA or to other devices(e.g. scanner) on K line by switching of a multiplexer and specific communication procedures. The multiplexer is a part of PCM/ECM H/W.
The ECM sets DTC P1694 if Request from EMS is invalid.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
- | 1. Faulty PCM/ECM ※ Protocol layer violation 2. Invalid request 3. Check sum error |
Enable Conditions |
•
IG ON | |
Threshold value |
•
Protocol layer violation
•
Invalid request
•
Check sum error | |
Detecting time |
•
- | |
FAIL SAFE |
•
- |
Fig.1) A normal signal waveform of antenna and immobilizer communication when IG key( TP : Transponder) is OFF to ON.