B1672
Seat Driver Occupied Input Circuit Failure
Body Chassis/Safety Occupancy Detection 🟢 Low — Fix at next service
💬
What This Actually Means
In plain language — no jargon

The car's seat occupancy sensor isn't sending a clear signal to the computer, like a light switch that's loose and flickering. This prevents the airbag and safety systems from knowing if someone is actually sitting in the driver's seat.

⚡
Symptoms You May Notice
3 known symptoms for this code
Airbag warning light illuminated on dashboard
Seat belt reminder not functioning properly
Airbag system disabled or inoperative
🔬
Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the seat occupancy sensor's analog voltage signal to detect if the driver's seat is occupied. The sensor should produce a stable voltage within a specific range; if the signal is erratic, absent, or out of bounds, the ECU logs a circuit failure. This input is critical for airbag deployment logic and safety system activation.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Seat Occupancy Voltage 0.5V - 4.5V stable Below 0.2V, above 4.8V, or erratic transitions
Signal Continuity Continuous, no dropouts Intermittent loss or open circuit
🔧
Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Seat occupancy sensor connector
Inspect and reseat the connector at the base of the driver's seat to ensure a solid connection.
2
Wiring harness
Check the wiring between the seat sensor and ECU for pinched, corroded, or damaged sections and repair as needed.
3
Seat occupancy sensor
Replace the sensor if voltage readings remain out of spec after connector and wiring checks.