All Doors Unlock Relay Circuit Failure
The vehicle's central locking system cannot engage the relay that unlocks all doors simultaneously, similar to a light switch that's broken and can't complete the circuit. The body control module detects the relay isn't responding when commanded to unlock.
The body control module sends a voltage signal to the all-doors-unlock relay and monitors the feedback circuit for proper relay activation. It detects if the relay coil isn't energizing or if the relay contacts aren't closing when commanded. A missing or abnormal feedback signal triggers the fault code.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Relay Coil Voltage | 12V activation signal present, 0V at rest | No voltage detected or stuck low/high signal |
| Relay Contact Resistance | Less than 0.5 ohms when closed | Infinite resistance or excessive resistance when relay commands activation |
Code B2250 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, B2250 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.