Illuminated Entry Input Circuit Failure
The vehicle's illuminated entry system (interior lights that turn on when doors open) has a wiring or sensor problem preventing the ECU from detecting door/sensor signals. Think of it like a doorbell where the button connection is broken, so the chime never rings.
The ECU monitors the illuminated entry input circuit for valid voltage signals from door switches or ambient light sensors. It expects a clean digital or analog signal within normal operating range when doors are opened or closed. If the signal is absent, shorted, or out of range for extended periods, the fault is logged.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Door Switch Signal Voltage | 0V (closed) to 12V (open) | Open circuit, short to ground, or floating voltage >2 sec |
| Circuit Resistance | <10 ohms per connection | >100 ohms or infinite resistance detected |
Code B1607 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, B1607 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.