Remote Keyless Entry Out of Synchronization
Your key fob and car's receiver have lost their synchronized signal codes, like two phones that can't communicate on the same frequency anymore. The car won't recognize your remote lock/unlock commands until they're re-paired.
The body control module monitors the rolling code synchronization between the key fob transmitter and receiver. Each fob transmission uses an incrementing code; if the receiver detects codes that are too far out of sequence or missing expected increments, it flags a synchronization fault. The system tracks valid code ranges and discards transmissions outside the expected window.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Rolling Code Sequence Gap | ±0-256 increments from last valid code | >256 increments or non-sequential pattern detected |
| Fob-to-Module Signal Recognition | Valid encrypted code received within sync window | Code rejected as out-of-sync or unrecognized encryption |
Code B2425 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, B2425 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.