What does it mean?
B2440 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Passenger Seat Back Heater Sensor Circuit .
Symptoms
- The airbag warning lamp is on continuously
- Passenger side curtain and side airbag protection is disabled
- The fault reappears immediately after clearing
- The problem first appeared after body repair, door work or seat removal
- No effect on drivability, but the restraint system is not fully functional
Likely causes
- Side impact sensor mounting bolt loose or not tightened to the specified torque
- Sensor mounted on a deformed or corroded panel following previous accident repair
- Wrong sensor or a sensor from a different variant installed in that location
- Cracked sensor bracket or a damaged mounting boss on the body
- Trim, sound deadening or sealant trapped between the sensor and the panel, preventing solid contact
- Internal sensor fault reported by the module as a mounting or plausibility error
- Corroded connector at the B-pillar or sill giving an unstable signal that the module interprets as a mounting fault
How to fix it
- Follow the restraints safety procedure, disconnecting the battery and waiting the specified time before touching any sensor
- Remove the trim to expose the passenger side impact sensor and inspect how it is mounted
- Confirm the mounting bolt is present, of the correct type and torqued to the manufacturer figure, since these sensors rely on rigid metal to metal contact to read an impact correctly
- Look for corrosion, panel deformation or previous repair at the mounting point and rectify the bodywork first
- Verify the sensor part number matches the vehicle specification
- Inspect and reseat the sensor connector, checking that the locking tab is fully engaged
- Replace the sensor if the mounting and wiring are correct and the fault remains, then clear the code and confirm the airbag lamp goes out