Circuit Description

Electronic Frontal Sensor (EFS), uses a unidirectional 2-wire circuit. EFS sensor modulates current on the interface to send identification, State Of Health (SOH) and deployment commands to Sensing and Diagnostic Module (SDM). SDM serves as a power source and ground for EFS. When ignition is turned on and EFS detects power from SDM, EFS responds by performing internal diagnostics and sending identification to SDM. SDM considers identification message to be valid if received within 5 seconds of EFS powering up. EFS continually communicates a status message to SDM. When fault is detected, SDM will attempt to reset EFS twice by removing and applying power. If fault is still present, SDM will set a DTC.