B1900 TOYOTA, SCION, LEXUS: SHORT IN FRONT DRIVER SIDE PRETENSIONER SQUIB CIRCUIT
POST UPDATED IN June, 2023
B1900 Code failures by brands
Description of DTC code B1900
The function of the driver’s side front pretensioner activation circuit is to tell the SRS (Supplemental Restraint System) when to deploy the pretensioner, taking into account the conditions that require it. The outside left front seat belt and the center airbag sensor are included for this circuit.
The OBDII diagnostic code B1900 for Scion, Lexus, and Toyota vehicles relates to a failure of the driver’s side front pretensioner activation circuit, which has a short.
Symptoms of fault code B1900
- The Check Engine light is illuminated.
- The lamp warning of an airbag system failure is ON.
Causes of OBD2 B1900
DTC B1900 OBD2 is set for one of the following reasons:
- Left seat belt circuit wires on the outside of the front seat may be faulty or damaged.
- The front seat LH (outside left) belt circuit connections may have some conditions that cause the short circuit.
- The front seat left outer belt (LH) may be defective.
- Possibly, the Center Airbag Sensor assembly could be deficient.
Possible solutions of the DTC code B1900
The steps to solve the B1900 OBDII fault code are:
- Consult the Technical Service Bulletins.
- Check all the wiring related to the left belt circuit on the outside of the front seat for common damage (corrosion, wear, or burns). Repair as required.
- By using the appropriate tools, take readings of the voltages corresponding to the left seat belt circuit on the outside of the front seat. Then, compare those values with the manufacturer's specifications. If you discover wide differences that indicate a short circuit, make the appropriate adjustments.
- Verify that the left outer belt corresponding to the front seat and the Center Airbag Sensor are not damaged. For this diagnosis, consider the manufacturer's recommendations. Consequently, make the required corrections.
