Car Problem Reports

Subaru Forester Check Engine Light Due to Failed Knock Sensor

Subaru Forester Problem
33 Reports
Me Too

Model Years Affected: 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

Average Mileage: 140,394 mi (30,789 mi - 240,000 mi)


The Check Engine Light may illuminate because of a failed knock sensor. Although the sensor often tests okay, it can fail intermittently, while the vehicle is being driven.

  • Visitor, , 30,789 mi

    The check engine has come on twice in the past two weeks and the code read (knock). The engine has always made some noise from a piston slap but the light has never came on before. Now,I am wondering if I have an engine problem.

    Answers anyone?

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  • Visitor, , 197,000 mi

    I had this same issue and reported it as well, but took it the shop and replaced the sensor as well as did a full tune up..All belts, Wires, Plugs and fuel filter and that fixed my check engine light as well as the A/T temp light

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  •  Rookie

    My forester severly hesitates then suddenly speeds up my check engine light does report back the knock sensor, does the symptoms sounds related to the sensor?

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  • Visitor, , 142,877 mi

    My knock sensor failed and check engine light turned on. Fixing issue.

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  • Visitor, , 164,765 mi

    check engine light on dealer checked an came saying is the knock senser

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  • Visitor, , 175,000 mi

    Check engine light on due to failed knock sensor and catalytic converter

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  • Visitor, , 109,000 mi

    check engine lite

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  • Visitor, , 123,000 mi

    CEL came on, seemed to run rougher, my mechanics put it on tester, drove it & report all was well after testing/driving- reset CEL. Cel came back on within a week, cruise control lights also flashing/disabled, mech says bring it by in am, hook it up & see if anything else involved. We shall see....

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  • Visitor, , 84,000 mi

    happens constanly

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  • Visitor, , 100,000 mi

    Check engine light was on and I discovered that it was the knock sensor. I replaced the sensor and even though I can hear slight detonation knocks, it is doing just fine after about a year.

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