The knock sensor on your 1997 Nissan Altima mounts to the side of the engine block and uses a piezoelectric element to sense vibrations from within the engine. These vibrations are converted to electrical pulses and sent to the engine’s computer. The computer may adjust the timing or the air-fuel mix to compensate and stop the knocking or premature detonation within the engine. The sensor does not fail often, so if you suspect yours is bad, have it tested before you buy a replacement sensor.
Open the hood of your Altima and locate the knock sensor on the top of the engine. The sensor is located on the passenger’s side of the engine block about halfway back and just below the cylinder head.
Disconnect the wiring harness connector from the knock sensor by releasing the locking tab and pull the connector off the sensor. Set the wire aside for now. Remove the bolt in the center of the sensor with a wrench and remove the sensor from the engine compartment.
Place the new sensor on the block and install the retaining bolt. Tighten the bolt with a wrench, making sure it is secure. Plug the wiring harness connector into the sensor, making sure the locking tab engages.
Start the engine in your Altima and verify that the repair was successful. If the car is running properly, you can close the hood and drive the car normally.
