Driver Side
The driver's side occupant detection system isn't communicating properly with the car's computer, like a passenger sensor that's not reporting whether someone is sitting there. This prevents safety features like airbags from working correctly on that side.
The ECU monitors the driver seat occupancy sensor to detect if someone is sitting in the driver's seat and their approximate weight. It uses this signal to determine if the driver airbag and safety systems should be armed. If the sensor signal is missing, out of range, or discontinuous, the ECU sets this fault code.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Seat Occupancy Signal Voltage | 0.5-4.5V (varies with weight) | Open circuit, short to ground, or no signal change |
| Signal Continuity | Continuous valid data every 100ms | Missing or erratic data for >500ms |
Code B1993 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1993 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.