Replacing the knock sensor on the Nissan Maxima is simple, but the sensor can be expensive, so be sure to have the car properly diagnosed before assuming the sensor is bad. The knock sensor detects engine knock or ping in the engine, then transmits data to the engine-management computer, enabling the computer to retard or make other critical adjustments to the timing, spark and fuel delivery.
Open the hood of your Maxima and locate the negative battery cable at the battery terminal. Using a wrench, remove the retaining bolt and separate the cable from the battery, isolating the cable while you work.
Locate the knock sensor on the top edge of the engine block on the right side of the engine. It is about halfway back and is a circular part with a bolt running through the center and an electrical connector on the outer edge. Disconnect the wiring harness connector from the knock sensor by lifting the locking tab slightly and then pulling the connector off the sensor.
Remove the bolt from the center of the knock sensor with a socket and ratchet, them remove the sensor from the engine block. Position the new sensor on the engine block and insert the retaining bolt through the center, threading it into the engine block.
Tighten the bolt with a socket and ratchet, then install the electrical connector on the sensor. Make sure you push the connector in enough for the locking tab to engage.
Connect the negative battery cable on the negative battery terminal. Install the retaining bolt and tighten it with a wrench. Close the hood of your Maxima.
