2000 Subaru Outback CEL code P1490 - what is it?

[ryu_haneda]

Just got it this afternoon on the drive home from work.

[97scoob]

P1490 Vacuum Cut Valve Bypass Valve (Circuit)
dont really know what that means but thats what i found when i looked it up... hope that can be of some help...

[decke48]

P1490 for subaru is thermostat malfuntion. since P1490 is a manufactor specify code it varies by manufactor.
idk how the ecu detect thermostat malfuntion.. a post on scoobymod the person replace the themostat and the CEL went away
http://www.scoobymods.com/forums/thermo ... amp;t=2639 (http://www.scoobymods.com/forums/thermostat_malfunction-t2639.html?s=29dd1d982d60a74c8577e364357f33fa&s=fed9d14d828d8f8c876136fa97722f4f&s=1465e4f0810d88d1e809199ac4cbb99e&s=fa7cb8a2708fd0d5042cef7d80c5d72c&s=24a135523f1570db128653743d5fcae8&s=905408c8920214eea6f642a221cde888&s=a8cac5ed724f8236888d98fb33c5fe8f&s=40b34b30826a392b4e2dd0e8cfce7a2b&s=6db777a9c689465d8956afb507ac8f04&s=aab6a1a62c275f2f14082a2790943886&s=5e3e9d86bc0951c7cad6ebac4889d519&s=82e3830101aea100b7d87641fab83f41&s=c33c3e1f2f327105c42f0dfc188cac18&s=9f406d34f17e3c16e194d0021956028e&s=9b16ccdcbdb083df86a1e10b0a1b3aac&s=87092d26fe3cf071b596cffc3e6a7a71&s=9607ca8477a83a85dbf3815f6ad6d3b8&s=ac3416d189d32e84f3ff0ece8113d2a5&s=ba24e60077725f2a878fb9b82dfa106f&s=33cf737b9a7e8dd1a18808f3204c6e58&s=c8fcd7fcc26eb988b7b4dd9ff8789716&t=2639)

[dplacencia]

I had a car at work that gave me a thermostat code. someone else replaced the t stat but the code came back. I ended up replacing the radiator cap and never had a problem again.

[Huffer]

So it's a pressurization thing with the cooling system. T-stat or the rad-cap...

Ramon - try checking to see if there's any visible leaking in the cooling system.

[ryu_haneda]

Problem solved! Faulty thermostat. Will be replaced shortly.