Servo Motor Potentiometer Defrost Circuit Open
The defrost control motor's position sensor has an open circuit, meaning the ECU can't read where the defrost door is located. It's like a broken feedback wire telling the engine computer if the defrost is open or closed.
The ECU monitors the potentiometer voltage from the defrost servo motor to verify door position feedback. When voltage signal is absent or outside expected range, the ECU detects an open circuit condition. The system requires continuous voltage feedback to validate defrost door operation and allow mode switching.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Potentiometer Voltage | 0.5V - 4.5V variable | Below 0.1V or above 4.9V (open circuit) |
| Signal Continuity | Continuous resistance change with motor movement | No signal variation or complete dropout |
Code B1269 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, B1269 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.