What does it mean?
B1790 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Airbag Sensor Assy Center Communication Circuit Malfunction .
Symptoms
- Airbag warning lamp lit and part or all of the restraint system deactivated
- Occupant detection or side impact functions unavailable
- Several restraint codes stored together, often naming different circuits
- Fault frequently appears after battery, console, carpet or seat work
- Communication with the restraint module on the scan tool may be slow or drop out
Likely causes
- Main connector at the airbag sensor assembly under the console not fully seated after carpet, console or seat work
- Corroded or wet pins in that connector after a drink spill or a leak into the footwell
- Break or short in the dedicated communication wiring between the sensor assembly and the peripheral unit
- A peripheral unit on the line, such as an occupant detection or satellite sensor module, failing and loading the circuit
- Low or unstable system voltage from a weak battery, which upsets module communication
- A replacement module that has not been configured or coded to the vehicle
- Internal fault in the airbag sensor assembly itself
How to fix it
- Test the battery and charging system; unstable voltage causes false communication faults
- Read every module on the vehicle and record the complete code set, not just this one
- De-energise the restraint system and observe the stand-down time before unplugging anything
- Reseat and inspect the airbag sensor assembly connector for corrosion, moisture, spread or backed-out pins
- Test the communication wiring for continuity, shorts to ground and shorts to power along its route
- Disconnect suspect peripheral units one at a time to see whether one of them is dragging the line down
- Confirm that any previously replaced module is correctly configured for the vehicle; replace the sensor assembly only as a last step