EIC Switch-1 Assembly Circuit Short To Battery
The EIC (Electronic Interior Control) switch circuit is shorted directly to battery power, like a wire touching the positive terminal when it shouldn't. The ECU detects abnormally high voltage on this circuit and sets the fault code.
The ECU monitors the voltage signal from the EIC Switch-1 assembly, expecting a variable voltage between ground and 5V depending on switch position. When a short-to-battery condition occurs, the circuit voltage remains stuck at battery voltage (12-14V), indicating a wiring or switch failure. The ECU triggers a fault when it detects sustained voltage above normal operating range.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| EIC Switch-1 Voltage | 0-5V variable with switch position | >10V (battery voltage detected) |
| Circuit Continuity Check | Proper isolation from battery rail | Direct short path to battery positive |
Code B1207 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, B1207 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.