thanx for any info

 

The Knock Sensor is located below the intake manifold. On my '99 Maxima it looks as if the KS can be R/R by person with good dexterity and a 1/4" drive socket wrench set. However, there is a test you may make without removing the KS.

1) Raise the hood. View the engine from the driver's fender. Look into the deep valley between the cylinder banks and below the intake manifold. Identify the KS as a black item fastened to the block by a single vertical bolt. A wire harness wrapped in black leads toward you, out of the valley. That is the KS sub-harness.

2) Follow the KS sub-harness to it's nearest connector. This is connector F121 in the FSM. It is located near the upper right-hand corner of the valve cover of the forward cylinder bank, as viewed from the front of the car.

3) Disconnect F121. You have to do a "press the latch, wiggle, and pull" maneuver to disconnect it. F121 has only two pins; if you see more than two pins, you have the wrong connector. Use a digital ohmmeter capable of measuring more than 10 Megohms. You want to measure the pins of F121, not the sockets of the matching connector. Measure the resistance between a good ground (such as the battery negative terminal) and terminal #1 of connector F121. On my car this is the higher of the two pins (the one closer to the sky). The factory spec is 500 - 620 Kohms.

 

FAQ MATERIAL!! Nice info.

 

thanks for the information I was trying to check between the terminals on the conector and i was knocking on the engine block and the ohm miter didn't show anything.

I will try your advice

I don't have the check engine light on but the code is in the computer

Does it effect the perfomance of my car ?

thanks

 

Possibly. The Engine Control Module responds to signals from the Knock Sensor by retarding the ignition timing. This is done to protect the engine from the damaging effects of pinging. If the KS is defective and sending wrong signals, your engine may be running with the wrong timing. The result would be diminished performance and fuel economy.