Left Lamp Outage Signal Circuit Short to Ground
The left exterior lamp circuit is shorted to ground, preventing the lamp from receiving proper power signals. Think of it like a water hose with a hole in it—the electrical current escapes instead of powering the light.
The ECU monitors the voltage and current draw of the left lamp circuit. When a short to ground occurs, current bypasses the lamp and flows directly to ground, causing abnormally high current draw or zero voltage at the lamp terminal. The ECU detects this abnormal condition and sets the fault code.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Lamp Circuit Voltage | 12V (battery voltage when activated) | 0V or abnormally low due to short to ground |
| Circuit Current Draw | Normal lamp amperage (varies by lamp type) | Excessive current draw or open circuit detection |
Code B2571 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, B2571 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.