Asking for a friend that got this code: P1446 Fuel Tank Sensor Control Valve Circuit Low.

According to AutoCodes, it could be:

  • Faulty fuel tank sensor control valve
  • Fuel tank sensor control valve harness is open or shorted
  • Fuel tank sensor control valve circuit poor electrical connection

Here's what he had tried:

  • Clear the code with a reader, but code comes back again.
  • Disconnect battery's negative terminal for 15 minutes, but code comes back again.
  • Turn ignition on, heard a 2 to 3 second high pitch wind blowing sound near the EVAP/charcoal canister.
  • Compared with a Camry for the high pitch sound, Camry sounds shorter and cleaner.
  • Other than that, the car starts and drives fine.

I'm looking at these parts but don't know which one is related to the high pitch sound:

Any ideas?

Update: Wonder if this tool can check purge valve?

1 Answer 1


"Circuit Low" immediately sounds like a voltage problem. I would begin by checking continuity with a multimeter from the sensor to your ecm (engine control module) and finding what voltages you should be reading. Then after digging around I found a forum post showing troubleshooting methods that one of your vents or line might be plugged up. The tool you linked might help but I'm unsure of how exactly you would implement it. Remember to always check your forums too! NASIOC (North American Subaru Impreza Owners Club) would be a great place to visit! Trouble shooting

Basic schematic

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