What does it mean?
B1794 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Occupant Classification ECU Battery Positive Line Open .
Symptoms
- Airbag warning lamp stays on after every start
- Passenger airbag ON/OFF indicator stuck in one state regardless of who sits there
- Passenger airbag may be deactivated even with an adult in the seat
- Occupant weight or seat status data missing or implausible on a scan tool
- Code sets again immediately after being cleared
Likely causes
- Open circuit or corroded terminal in the battery positive feed to the occupant classification ECU
- Blown or loose fuse supplying the passenger seat occupant classification circuit
- Chafed or broken harness under the passenger seat, damaged by seat travel or floor cleaning
- Module connector not fully seated after seat removal, trim work or airbag service
- Poor module ground that makes the supply line read as open
- Water or spilled liquid reaching the under-seat connector and corroding the pins
- Internal failure of the power input stage inside the occupant classification ECU
How to fix it
- Check and load-test the fuse feeding the occupant classification ECU
- Inspect the under-seat connector for spread, pushed-out or corroded terminals
- Back-probe the supply pin and measure battery voltage with the key on
- Perform a voltage drop test on both the supply wire and the module ground
- Flex the under-seat harness while watching the voltage to catch an intermittent open
- Repair the open section and renew damaged terminals rather than splicing at the connector
- If supply and ground are good and the code remains, replace the module and run the required seat weight calibration