Knock Sensor: Testing and Inspection

1990 Subaru XT-6 4WD L6-2.7L SOHCSECTION Testing and Inspection

Knock Sensor Schematic:





A faulty knock sensor will set code 22 in the on-board diagnostic system. Refer to the schematic diagram and test the sensor with the diagnostic chart.

Wire color code identification:

L: Blue
B: Black
Y: Yellow
G: Green
R: Red
W: White
Br: Brown
Lg: Light green
Gr: Gray

Knock Sensor Diagnostic Chart:





KNOCK SENSOR DIAGNOSTIC CHART

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.