B0101 GMC, BUICK, CADILLAC, CHEVROLET, PONTIAC, SATURN: DRIVER-SIDE EFS NOT OKAY MESSAGE
POST UPDATED IN February, 2023
B0101 Code failures by brands
Description of DTC code B0101
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.
Symptoms of fault code B0101
- Check Engine Lamp ON.
- The airbag warning light turns on.
Causes of OBD2 B0101
Reasons to set the B0101 OBD2 fault code :
- The driver's side front electronic sensor wires may be damaged.
- The electrical connections in the driver's side Front Electronic Front Sensor circuit may be in poor condition.
- The Electronic Front Sensor on the driver's side could be faulty.
- The Detection and Diagnostic Module may be deficient.
Possible solutions of the DTC code B0101
To troubleshoot the DTC B0101 OBDII code, consider this:
- Check the wiring and connections associated with the Driver's Side Front Electronic Sensor. Check them for wear, corrosion, or burns. If any of these conditions are found, make the appropriate adjustments.
- Check the integrity of the Electronic Front Sensor on the driver's side. To do this, it is recommended that you follow the guidance provided in the manufacturer's information source. If you determine that it is faulty, replace it.
