Seat Switch Reference Voltage Positive Common Supply Low Voltage
The seat occupancy sensor circuit isn't receiving enough electrical power from the main supply—think of it like a weak battery trying to power a device. The ECU detected the reference voltage dropped below normal, preventing proper seat detection.
The ECU monitors the positive reference voltage supplied to seat switch circuits, typically around 5V. When this supply voltage drops below a threshold (usually 4.5V or lower), the ECU triggers a fault code because seat detection becomes unreliable, compromising airbag deployment logic.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Seat Switch Reference Voltage | 4.8–5.2V | Below 4.5V |
| Supply Current Draw | 50–200mA per circuit | Insufficient voltage under load |
Code B2343 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, B2343 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.