B1861 SCION, LEXUS, TOYOTA: DRIVER'S SIDE KNEE AIRBAG CIRCUIT OPEN
POST UPDATED IN February, 2023
B1861 Code failures by brands
Description of DTC code B1861
The Knee Airbag circuit is composed of the Center Airbag Sensor group and the Side Knee Airbag group. This circuit has the function of instructing the SRS (Supplemental Restraint System) to deploy after the conditions for such action are met.
The B1861 OBD2 diagnostic code setting occurs when a problem is detected in the driver’s knee airbag circuit. The code specifically indicates that an open circuit has been detected.
Symptoms of fault code B1861
- Check Engine light illuminated.
- The airbag trouble light illuminated.
Causes of OBD2 B1861
The reasons for storing the B1861 OBDII fault code are as follows
- The driver's knee airbag assembly wiring may have been damaged.
- Connections related to the driver's knee airbag assembly may be in poor condition.
- The driver's knee airbag assembly (driver's side knee Squib) may be defective.
- The center airbag sensor assembly could be defective.
Possible solutions of the DTC code B1861
To troubleshoot DTC B1861 OBD2 consider the following:
- As a first step consult the TSB.
- Verify that there are no damages to the cables and connectors related to the driver's knee airbag If you discover conditions caused by wear or burn points, proceed with the necessary adjustments.
- Measure the voltages of the driver's knee airbag assembly circuit and compare these values with those indicated by the manufacturer. As the code indicates the presence of an open circuit, check the integrity of the connections. Repair it as applicable.
- Following the recommendations indicated in the vehicle's information source, check that the driver's knee airbag assembly and the center airbag sensor assembly meet factory specifications. If deficiencies are found in either of these, make the appropriate corrections.
