Mirror Passenger Right Circuit Open
The passenger side mirror has a broken electrical connection, like a lamp with a loose wire that won't turn on. The car's computer detects the circuit is open and can't send power to the mirror's motors.
The ECU monitors the electrical circuit resistance and current draw when the mirror control switch is activated. It expects a closed circuit with measurable resistance from the motor load. When no current flows or resistance is too high, the ECU detects an open circuit condition.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Mirror Circuit Current | 0.5-2.5 Amps during motor operation | Less than 0.1 Amps or no measurable current |
| Circuit Resistance | 4-12 Ohms with motor engaged | Infinite resistance (open circuit detected) |
Code B1644 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, B1644 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.