Driver Power Window Down Circuit Open
The driver's side power window down circuit has an open connection, meaning electricity can't flow to operate the window downward. It's like a broken wire in a lamp that prevents the light from turning on.
The ECU monitors voltage and current flow through the driver window down circuit when the down button is pressed. It expects to detect a specific current draw through the motor relay circuit; an open circuit results in zero or no expected current flow, triggering the fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Circuit Current Draw | 2-5 amps when down button pressed | 0 amps or no current detected |
| Circuit Voltage | 12V+ at motor when activated | 0V or below threshold voltage |
Code B1404 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, B1404 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.