B1909 LEXUS, SCION, TOYOTA: SHORT IN FRONT DRIVER SIDE PRETENSIONER SQUIB CIRCUIT
POST UPDATED IN June, 2023
B1909 Code failures by brands
Description of DTC code B1909
The front driver’s side pretensioner ignition circuit is composed of two elements: the center airbag sensor assembly and also the front seat left outside (LH) belt. The function of this circuit is to command the Supplemental Restraint System (SRS) to deploy when conditions warrant.
When the B1909 OBD2 fault code is stored on Lexus, Scion, Toyota vehicles, it means that a malfunction was detected in the driver’s side front pretensioner activation circuit. Specifically, the code indicates that the circuit is shorted.
Symptoms of fault code B1909
- Check Engine lamp ON.
- The airbag light turns on.
Causes of OBD2 B1909
The B1909 OBDII diagnostic code is set for the following reasons:
- Left outside (LH) front seat belt cables or connectors may be damaged.
- The left front seat belt LH (front driver's side pretensioner squib) may be defective.
- The center airbag sensor assembly may be in poor condition.
Possible solutions of the DTC code B1909
To troubleshoot DTC B1909 OBD2, try this:
- Consult the TSB (Technical Service Bulletins).
- Check the front seat left outboard (LH) belt wiring. Verify that it is not deficient due to corrosion or wear. If one of these conditions is discovered, make the appropriate repairs.
- Measure the voltages of the left outboard belt (LH) circuit of the front seat to rule out shorts or an open circuit. Look for poor or bad connections. Repair if necessary.
- Check the good condition of the left outer belt (LH) of the front seat and the center airbag sensor For these tests, take into account the manufacturer's recommendations, and if you discover deficiencies, make the appropriate corrections.
