Mirror Passenger Right Circuit Failure
The passenger side mirror's electrical circuit has failed, similar to a broken wire preventing a lamp from turning on. The vehicle's control module detected an open circuit, short, or power loss in the mirror system.
The ECU monitors voltage and current flow through the passenger mirror motor circuit when the control switch is activated. It detects faults by sensing open circuits (no current), shorts to ground, or voltage drops exceeding normal operating thresholds. The module expects proper feedback when mirror commands are issued.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Mirror Motor Supply Voltage | 11.5-14.5V when activated | Below 3V or open circuit detected |
| Motor Current Draw | 0.5-2.5A during operation | No current or excessive draw (short) |
Code B1643 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, B1643 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.