2003 Subaru Forester Check Engine Light Due to Failed Knock Sensor

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.

Affected Model Years

This issue affects Subaru Forester model years 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, .

53 people reported this problem

  • 2003 30,789 Miles
    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?

  • 2003 190,856 Miles
    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?

  • 2003 175,000 Miles
    Check engine light on due to failed knock sensor and catalytic converter

  • 2003 100,000 Miles
    CHECK ENGINE LIGHT HAS BEEN ON FOR 10 YEARS. REPLACED OXYGEN SENSOR TWICE AND KNOCK SENSOR AND TIRED OF REPLACING THEM. SO, IT NOW HAS 175,000 MILES ON IT AND KNOCK SENSOR STILL NEEDS TO BE FIXED. SICK OF FIXING IT. WISH THE CHECK ENGINE LIGHT WOULD JUST BURN OUT.

  • 2003 149,000 Miles
    check engine light on, OBD-ll code P0328 knock sensor circuit, high voltage input. bought part online and will install myself

  • 2003 123,000 Miles
    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....

  • 2003 140,000 Miles
    Check engine light came on and the diagnostic code indicated bad knock sensor, located knock sensor and removed, founf it had a cracked housing. Replaced knock sensor and reset code. Now have 160,000 mile with no further problems.

  • 2003 142,877 Miles
    My knock sensor failed and check engine light turned on. Fixing issue.

  • 2003 109,000 Miles
    check engine lite

  • 2003 84,000 Miles
    happens constanly

  • 2003 197,000 Miles
    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

  • 2003 199,900 Miles
    Check engine light came on. Then off. 2 weeks later it came back on and stayed on. It's at the dealership now, parts and labor $ 352. I'm researching right now to see the cost of the part and how to do it myself. It appears to be about an $ 8 part. And it may be slightly difficult to replace it myself without the tools. Looks like I need a extended socket wrench.

  • 2003 0 Miles
    they cannot seem to fix it

  • 2003 164,765 Miles
    check engine light on dealer checked an came saying is the knock senser

  • 2003 240,000 Miles
    knock sensor failed but good sensor havent fixed yet

  • 2003 200,000 Miles
    Replaced 2.5 with 2.0 Japanese Import. Could not get rid of knock sensor error, drove car anyway. Did not run all that well. Poor fuel mileage. I thought it was due to smaller engine. Was most likely due to knock sensor retarding timing and increasing fuel. Eventually it stressed and broke the timing belt, and thus toasted the engine. Replaced with 2.5L, but used same intake manifold. Used 2.5 shows knock sensor code as well. Not fixed yet, but not going to risk another timing belt and engine with it this time.

  • 2003 100,000 Miles
    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.

  • 2003 61,000 Miles
    CEL came on as knock sensor reading low. Changed knock sensor with a aftermaket (Bosch I think) and CEL went off and trouble code never came back.

  • 2003 72,000 Miles
    check engine light