B0104 Code: Meaning, Causes, and Symptoms | OBD2 Codes

B0104 – Passenger-Side EFS Not Okay Message


B0104 Possible Symptoms


Air Bag Warning Light ON


B0104 Possible Causes


Faulty Passenger-Side Electronic Frontal Sensor (EFS),Passenger-Side Electronic Frontal Sensor (EFS) harness is open or shorted,Passenger-Side Electronic Frontal Sensor (EFS) circuit poor electrical connection,Faulty Sensing and Diagnostic Module (SDM)


B0104 Description


Electronic Frontal Sensor (EFS), also known as a front end sensor, 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). The 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 Diagnostic Trouble Code (DTC).