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 PCM/ECM sets DTC P1694 if Request from EMS is invalid.
Item
Detecting Condition
Possible Cause
DTC Strategy
-
Faulty PCM
? Protocol layer violatio
- Invalid requestn
- Check sum error
Enable Conditions
IG ON
Threshold value
Protocol layer violation
- Invalid request
Detecting time
-
Fail Safe
Fig.1) A normal signal waveform of antenna and immobilizer communication when IG key(TP : Transponder) is OFF to ON.