EIC Switch-1 Assembly Circuit Failure
The engine's electrical seat control switch isn't sending the right signal to the computer, like a light switch that's broken and won't tell the dimmer if it's on or off. This prevents the seat adjustment system from working properly.
The ECU monitors the voltage and resistance signals from the EIC (Electronic Integrated Control) switch assembly to verify proper seat switch operation. When the switch is activated, it should produce a valid voltage signal within expected parameters; a missing, intermittent, or out-of-range signal triggers this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Switch Signal Voltage | 0.5V to 4.5V (varies by switch position) | Below 0.1V or above 5.0V, or no signal detected |
| Switch Response Time | Signal change within 500ms of button press | No signal change or delayed response exceeding 2 seconds |
Code B1205 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, B1205 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.