Seat Switch Reference Voltage Negative Common Open Circuit
The seat switch circuit has a broken ground connection, preventing the ECU from detecting whether someone is sitting in the seat. It's like a light switch with a severed wire—the signal can't complete its path back to ground.
The ECU monitors the seat switch circuit by applying a reference voltage and measuring the return signal through the negative common ground. When seated, the switch completes the circuit to ground, pulling voltage low. An open circuit prevents this signal return, leaving voltage hanging high.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Seat Switch Reference Voltage | 0.2–0.8V (seated) or 4.5–5.0V (unoccupied) | Stuck high at 5.0V or no signal transition |
| Ground Path Continuity | < 1 ohm resistance to chassis ground | > 10 ohm resistance or open circuit |
Code B2345 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, B2345 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.