Mirror Switch Reference Voltage Negative Common Open Circuit
The mirror control switch's ground connection is broken, like a light switch with a severed wire preventing current flow. The ECU can't detect the switch position because the negative voltage reference path is open.
The ECU monitors the voltage reference signal on the mirror switch circuit ground line. When a switch is pressed, the ECU expects to see a voltage change indicating the switch closure. An open circuit in the negative common path prevents this voltage transition, causing the ECU to detect no signal.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Ground Reference Voltage | 0V (solid ground connection) | Floating or undefined voltage (open circuit detected) |
| Switch Signal Detection | Voltage transitions when button pressed | No voltage change or infinite resistance detected |
Code B2349 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, B2349 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.