Fuel Tank Pressure Sensor Circuit Open
The fuel tank pressure sensor's electrical connection is broken or disconnected, like a phone with a severed charging cable. The engine control module can't read fuel tank pressure data and triggers this fault.
The ECM monitors voltage signals from the fuel tank pressure sensor to detect evaporative emission leaks and fuel system faults. The sensor should return a valid signal within a specific voltage range; an open circuit produces zero or no signal, indicating a wiring or connector failure.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor voltage | 0.5–4.5 volts (depends on pressure range) | No voltage or out-of-range (open circuit detected) |
| Signal continuity | Continuous valid signal | Intermittent or absent signal for >2 seconds |
Code B1220 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, B1220 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.