The knock sensor in a Nissan Xterra performs a critical job. It "listens" to your engine to make sure that the engine is firing properly. If too much fuel gets into the engine, the compression is high enough, and the timing of the spark plugs is not precise enough, the pistons inside the engine can literally bang against the cylinder walls of the engine. This is called engine knock, and it can quickly cause catastrophic engine failure in your Xterra. When the knock sensor in your Xterra fails, you'll notice a marked decrease in fuel economy as the engine tries to retard ignition timing enough so that the engine "runs rich" (burns a lot of fuel). This will ensure that the engine does not suffer from knocking, but it also hampers fuel economy as well as engine performance.
Things You'll Need
- Socket wrench with socket set
- New knock sensor
Remove the bolt securing the knock sensor. The knock sensor is mounted behind the intake manifold on your engine, near the firewall. This is the hardest part about changing the sensor because it's a difficult location to reach. The sensor looks like a small doughnut-shaped component with a rubber top and an electrical-plug connector coming off one side of the sensor.
Remove the electrical plug by pulling it straight off the sensor and pulling the sensor out of the engine bay.
Plug the new sensor into the factory-wiring harness. Make sure you plug the sensor in before bolting it up. If you try to bolt the sensor first and you accidentally drop the sensor, it will most likely be damaged and unusable.
Align the mounting hole in the center of the sensor with the mounting hole on the engine. Bolt the sensor to the engine and tighten to 20 lb.-ft. maximum ("lb.-ft" refers to the "tightness" of the bolt and measures the force of one pound acting from a distance of one foot perpendicular to a given pivot point). Since you cannot really get a torque wrench in there for an exact torque measurement, 20 lb-ft. is just slightly tighter than hand-tight. Do not over-tighten the knock sensor or you will damage it.
- Nissan Frontier, Xterra Repair Manual 2005-2008; Jay Storer; 2008
Knock Sensor Replacement Procedure
The knock sensor in your car detects a low-frequency engine knock and sends an electrical signal to other parts of your car....
How to Replace the Knock Sensor
Automakers begin using computerized engine controls starting in the 1980s. Modern computerized engines utilize a spark knock sensor to detect detonation. Detonation...
How to Replace a P0325 Knock Sensor on a '97 Nissan Altima
The knock sensor on your 1997 Nissan Altima mounts to the side of the engine block and uses a piezoelectric element to...
How to Install a Knock Sensor on a '96 Nissan Altima
You can replace the knock sensor on your 1996 Nissan Altima at home and save yourself some hard earned money while feeling...
How to Replace a 2003 Nissan Xterra Knock Sensor
The 2003 Nissan Xterra uses a knock sensor mounted to the exterior of the engine block to determine if there are vibrations...
How to Replace a Knock Sensor in a Nissan Maxima
Replacing the knock sensor on the Nissan Maxima is simple, but the sensor can be expensive, so be sure to have the...
How to Remove the Nisson Sentra's Knock Sensor
The Nissan Sentra's knock sensor senses vibrations in the cylinder and sends a signal to the vehicle's computer to make the appropriate...
How to Replace the Knock Sensor on a 1997 Pathfinder
The knock sensor is responsible for monitoring the engine block for abnormal vibrations or internal components running out of balance. The sensor...
2002 Xterra Knock Sensor Issues
Introduced in 2000 in North America, the Xterra is a simple but capable compact SUV manufactured by Nissan. Marketed to adventurous people...