B1674

Step 1: Perform a visual inspection of all wiring and connectors under the driver's seat, checking for obvious damage, chafing against seat rails, pinched wires, or signs of previous repairs. Move the seat fully forward and backward while inspecting the harness routing.

Step 2: Disconnect the seat occupancy sensor connector at the seat base and use a digital multimeter to measure voltage on the signal wire at the harness side (vehicle side). With ignition on, you should read 0 volts or a low reference voltage (typically 0-5V depending on manufacturer). If you read battery voltage (12V+), the short is in the harness between the connector and BCM.

Step 3: If no voltage is present at the disconnected harness, measure resistance between the sensor connector signal pin (sensor side) and battery positive. Reading should be infinite (open circuit). Low resistance indicates an internal sensor fault.

Step 4: Inspect the connector pins for corrosion, bent pins, or moisture. Check terminal fit and ensure no cross-contamination between adjacent circuits. Clean and repair connector as needed.

Step 5: If wiring and sensor test good, check for water intrusion in the carpet area and BCM location. Test BCM ground circuits for integrity and verify no aftermarket accessories are tapping into related circuits.

Step 6: Clear codes, reconnect all components, cycle the ignition, and perform a road test with seat occupied and unoccupied conditions. Verify the code does not return and the airbag warning light remains off.