Introduced in 2000 in North America, the Xterra is a simple but capable compact SUV manufactured by Nissan. Marketed to adventurous people and built for rigid off-road terrain, the Xterra experiences a lot of engine load and vibration that could cause knock sensor failure.
Attached to the cylinder block, the knock sensor senses engine knocking using a piezoelectric element, which detects vibrational pressure. It is then converted into a DC voltage signal and sent to the engine control module (ECM).
Once knock starts, performance decreases and there is a risk of serious engine damage. A bad sensor can also be the cause of sluggish acceleration, especially on highway cruise at less than wide open throttle. During mild acceleration, you can experience sudden loss of power. You also may get a minor decrease in fuel economy. Xterras will behave differently when experiencing knock sensor issues due to differences in condition, software, gasoline, temperature and location.
It will only take few minutes to measure knock sensor resistance once you have test equipment like a digital voltmeter. However, service and repair of the knock sensor will require removal of the intake manifold.
Knock sensors are still supplied by Nissan and the recommended manufacturer's price as of February 2011 is $191. The OEM part number is 220607B000. If you decide to replace the knock sensor, be sure to tighten it applying 16 to 19 foot-lbs. of torque.
