How to Change the Knock Sensor on a 1995 Subaru Impreza

In 1968, Subaru made its debut on American soil with the release of the "360" economy vehicle. Subaru actually advertised the 360 as "Cheap and Ugly does it," so needless to say it was not too popular. Subaru hummed along as just another automobile manufacturer through the 1970s, and hit its stride come the 1980s and 1990s. The 1993 release of the Imprezza marked the coming-of-age for the Subaru lineup, as it won three straight World Rally Championships. The 1995 Imprezza came standard with a 1.8-liter four-cylinder engine, and had an optional 135-horsepower, 2.2-liter engine connected to Subaru's all-wheel-drive system. Replacing the knock sensor on the 1995 Imprezza is a fairly simple procedure, once you find it.

Instructions

1

Look on the driver's side, rear of the engine block and find the knock sensor -- it's a circular, black component with wires coming from it.

2

Trace the knock sensor's wiring until you come to where the sensor's wiring harness plugs into the Imprezza's wiring harness. Press the locking button on the Imprezza's wiring harness and pull it from the sensor's wiring harness.

3

Insert the blade of a flat-head screwdriver under the sensor's wiring harness, and pry it from the engine block to disengage its retaining clip. Remove the knock sensor-retaining bolt, using a ratchet and socket, and pull the knock sensor from the engine block.

4

Set a new knock sensor on the engine block with its flat, metal side contacting the engine block. Hand-tighten the knock sensor-retaining bolt, then tighten the bolt with a ratchet and socket.

5

Line the retaining clip on the wiring harness with the hole in the engine block, then press the harness onto the block until the retaining clip snaps into place. Plug the Imprezza's wiring harness into the knock sensor's wiring harness.