Detent Signal Missing During Unlatch
Your vehicle's door latch isn't sending a signal to confirm it has unlocked when the system tries to open it. Think of it like a door lock that won't report back whether it actually unlocked or not.
The ECU monitors the detent signal from the door latch actuator to confirm the latch mechanism has disengaged during an unlock command. The signal should transition from locked to unlocked state within a specific timeframe. If no signal change is detected, the ECU logs this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Detent Signal Response Time | Signal transitions within 500-800ms of unlock command | No signal transition or delayed beyond 1.5 seconds |
| Signal Voltage Level | Transitions between 0.5V (locked) and 4.5V (unlocked) | Remains stuck at one voltage or below 0.2V |
Code B2591 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, B2591 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.