What does it mean?
B1400 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver Front Side Impact Sensor (FSIS) Circuit Fault .
Symptoms
- SRS lamp on with the driver side and curtain airbags disabled
- The fault often appears after door trim, window regulator, speaker or mirror work
- It can be intermittent and set when the driver door is slammed
- Other driver side restraint codes may be stored alongside it
- No effect on how the vehicle starts or drives
Likely causes
- Sensor connector at the driver door or lower B-pillar loose, damp or corroded
- Broken conductor in the driver door harness inside the rubber hinge boot
- Sensor mounting bolt loose or the bracket bent, so the sensor loses its solid reference to the body
- Sensor damaged by an earlier impact or during door repair, and reused when it should not have been
- Chafed sensor wiring behind the door trim or the kick panel
- Water entering the door after the vapour barrier or a window seal failed
- Airbag control module communication or supply fault to that sensor
How to fix it
- Read all restraint codes and note whether the fault is current or historic and whether door slamming reproduces it
- Power the system down safely, disconnect the battery and wait the reserve power discharge time
- Inspect the sensor, its connector and its mounting; confirm the bolt is tight and the sensor sits flat against the body
- Flex the harness inside the door hinge boot while the circuit is monitored, since this is where conductors break
- With both ends unplugged, check the sensor circuit for continuity and for isolation from ground and from power
- Compare the readings with the passenger side sensor circuit, which is a useful reference on the same vehicle
- Replace the sensor if the wiring is good; never reuse a sensor recovered from a collision-damaged vehicle, and torque the new one to specification