Lamp Keypad Output Open Circuit
The lamp keypad circuit that controls interior lighting buttons has an open connection, like a broken wire preventing electricity from flowing. The vehicle's body control module detects this break and triggers the fault code.
The body control module monitors voltage at the lamp keypad output circuit, expecting a closed loop with proper voltage levels when buttons are pressed. An open circuit causes voltage to remain at zero or float indefinitely, triggering a fault detection.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Keypad Output Voltage | 5V or 12V depending on circuit design | 0V or open circuit (no continuity) |
| Circuit Continuity | Continuous path with <5 ohms resistance | Infinite resistance (open circuit condition) |
Code B1624 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, B1624 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.