What Does B1673 Mean?
This code indicates the Body Control Module (BCM) has detected an open circuit in the driver's seat occupancy sensor system. The occupancy sensor, typically a pressure-sensitive mat or weight sensor integrated into the seat cushion, monitors whether the driver's seat is occupied. An open circuit means the BCM is not receiving a valid signal from the sensor, preventing proper operation of safety systems like airbag deployment logic and seatbelt reminder warnings.
Common Causes
35%
Damaged or disconnected wiring harness connector under driver's seat
30%
Broken or corroded wires in the seat track area due to seat movement and wear
25%
Failed seat occupancy sensor mat or pressure sensor
10%
Internal BCM fault or blown fuse in occupancy sensor circuit
Diagnostic Steps
1
Step 1: Visually inspect the driver's seat area by sliding the seat fully forward and backward. Look under the seat for disconnected connectors, damaged wiring, or obvious physical damage to the sensor mat
2
Step 2: Using a digital multimeter set to continuity mode, test the wiring harness from the seat occupancy sensor connector to the BCM connector for open circuits or high resistance (should be less than 5 ohms)
3
Step 3: Check for proper voltage supply at the occupancy sensor connector with ignition ON. Verify reference voltage (typically 5V) and ground using a multimeter
4
Step 4: Monitor live data from the occupancy sensor using the scan tool while applying weight to the driver's seat. The sensor should show a change in status from 'unoccupied' to 'occupied' when weight is applied
5
Step 5: If all wiring and connections test good, replace the seat occupancy sensor mat and verify proper installation. Clear codes and retest the system to confirm repair
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an open circuit in the driver's seat occupancy sensor system. The occupancy sensor, typically a pressure-sensitive mat or weight sensor integrated into the seat cushion, monitors whether the driver's seat is occupied. An open circuit mea...
The most common cause of B1673 (Seat Driver Occupied Input Circuit Open) is: Damaged or disconnected wiring harness connector under driver's seat
Typical repair costs for B1673 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle is safe to drive, but airbag deployment calibration and seatbelt warning systems may not function correctly. Repair should be completed promptly as this affects supplemental restraint system operation and may prevent proper airbag deployment in a collision.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1673 to identify the root cause.
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Quick Info
Category
Body
System
Body Control System / Occupant Safety System
Difficulty
Type
Manufacturer
Recommended Tools
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