B0101 GMC, BUICK, CADILLAC, CHEVROLET, PONTIAC, SATURN: DRIVER-SIDE EFS NOT OKAY MESSAGE
POST UPDATED IN February, 2023
B0101 GMC, BUICK, CADILLAC, CHEVROLET, PONTIAC, SATURN: DRIVER-SIDE EFS NOT OKAY MESSAGE
The EFS (Electronic Front End Sensor) is also called the Front End Sensor. This sensor uses a unidirectional 2-wire circuit. This device modulates current at the interface to send identification, state of health (SOH), and display commands to the Sensing and Diagnostic Module (SDM). At the same time, the SDM also works as the power and ground source for the sensor.
When the power is turned on and the EFS detects power from the SDM, the sensor responds by performing an internal diagnostic and sending the ID to the SDM. Only if the ID message is received within 5 seconds of the EFS power-up, it is considered valid.
If a fault is detected, the SDM will attempt to reset the EFS twice by canceling and applying power. If the fault remains, the SDM will set the B0101 OBDII diagnostic code.
Reasons to set the B0101 OBD2 fault code :
To troubleshoot the DTC B0101 OBDII code, consider this: