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2004 Subaru Impreza 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 Impreza model years 2004, 2005, 2006, 2007, 2008, 2009, 2010, .

10 people reported this problem

  • 2004 30,000 Miles
    Sensor replaced approximately every six months since 30,000 miles. Maintain General maintenance. Getting very frustrated with Subaru!
  • 2004 128,700 Miles
    I just bought a used 2008 WRX, just a couple hours later the engine light came on with a misfire code. Went back to the dealer, they replaced the spark plugs & coils, and checked everything out. Two days later another engine light with a O2 sensor, bank 1. They cleared the code, asked me to drive again. Four days later engine light on again after I pushed the car high speed on the highway. Autozone told me, O2 sensor again - but then the light went off by itself. I'm very confused - does the car have a problem or not?

Subaru Impreza 2004 Common Problems