Parklamp Output Relay Driver Circuit Failure
The parking lamp relay driver circuit in your vehicle's control module isn't working properly, similar to a light switch that can't turn on or off the lights. This prevents the park lamps from functioning correctly.
The ECU monitors the park lamp relay driver circuit by measuring voltage and current output to the relay coil. It detects open circuits, short circuits, or excessive current draw that indicate driver failure. If the circuit cannot achieve proper voltage or current levels, the fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Relay Driver Output Voltage | 11-14V when activated | Below 8V or no voltage |
| Relay Driver Current Draw | 150-500mA | Exceeds 1000mA or zero current |
Code B2251 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, B2251 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.