Window Feedback Failure
The car's computer can't detect proper window movement feedback from the motor or switch. It's like a light switch that doesn't send a signal back to confirm the light actually turned on.
The ECU monitors voltage feedback from the window motor circuit and position sensors to verify window movement. It detects open/short circuits or missing signals when the motor should be operating. If feedback voltage doesn't match expected patterns within time thresholds, the fault is logged.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Motor feedback voltage | Varies per window position (0-5V range) | No signal, stuck voltage, or signal timeout >2 seconds |
| Circuit resistance | <10 ohms motor circuit | >25 ohms or open circuit detected |
Code B1235 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, B1235 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.