B1821 SCION, LEXUS, TOYOTA: OPEN IN DRIVER SIDE - SIDE SQUIB CIRCUIT
POST UPDATED IN January, 2023
B1821 Code failures by brands
Description of DTC code B1821
The driver’s side Squib circuit is composed of the center airbag sensor assembly and the left front seat (LH) side airbag assembly. It sends the corresponding signals to the SRS (Supplemental Restraint System) to be deployed once the conditions are met.
When the B1821 OBDII diagnostic code B1821 is stored, it means that the Driver Side Squib circuit has had a malfunction due to an open circuit.
Symptoms of fault code B1821
- Check Engine lamp illuminated.
- Airbag malfunction light ON.
Causes of OBD2 B1821
Reasons for setting the DTC B1821 OBD2 code:
- The wiring of the left front side airbag assembly may be faulty.
- The electrical connections of the left front side airbag assembly circuit may be in poor condition.
- The left front seat side airbag assembly (LH) may be malfunctioning.
- The center airbag sensor assembly may be faulty.
Possible solutions of the DTC code B1821
To troubleshoot the B1821 OBDII fault code, try this:
- First, consult the TSBs (Technical Service Bulletins).
- Check the cables related to the left front side airbag assembly for common deficiencies. If wear or burns are found, make the appropriate repairs.
- Measure the circuit voltages of the left front side airbag assembly and check that these values are within the range established for proper operation. If deficiencies are found that indicate the cause of the open circuit, make the appropriate corrections.
- Check the condition of the left front side airbag assembly and the center airbag sensor. Take into account the manufacturer's recommendations to carry out such a diagnosis. If you detect common damage, make the corresponding adjustments.
