Door Ajar Lamp Circuit Short To Battery
The door ajar warning light circuit is shorted directly to battery voltage, preventing the ECU from controlling it properly. Think of it like a light switch that's stuck in the on position because the wire bypassed the switch entirely.
The ECU monitors the door ajar lamp circuit voltage by controlling a ground path or low-side driver. It expects to see near battery voltage when the lamp should be off and near ground when activated. A short to battery bypasses the ECU's control, forcing the circuit to remain high regardless of door switch input.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Lamp Circuit Voltage | 0.5V-2V (off) / 10V+ (on when commanded) | Constant 12V+ regardless of door state |
| ECU Control Signal | Toggles 0V-12V based on door switch input | Unable to pull circuit low; no control response |
Code B1325 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, B1325 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.