Question

P0325 NISSAN - knock sensor 540 kΩ but 5v dc when the engine on. what else can cause this?

Answer 1

You need to check for voltage drop at the sensor. Under load the sensor reacts in different way. More than likely under load the sensor circuit gets open. Replacing he sensor usually fix the problem.

There is a tutorial to relocate the knock sensor in case you don't want to remove the intake manifold to replace it.

Knock Sensor Relocation Tutorial: http://x.nissanhelp.com/forums/pathfinder/7890-3-3l-knock-sensor-relocation.html