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I guess I stand corrected.

After re-reading your initial post. Did you replace the sensor, or just relocate it?

One of the possible issues you're having is that the new location may be picking up excessive noise from the supercharger. Try moving the location to where 2002XterraSC describes, reset the codes and see if the problem is solved. You could also try to find a location that is actually on the engine block, which is preferable.
That is exactly what is happening. My roommate had an 02 SC as well, and we tried several different bolts on the SC before realizing this. I believe he ended up bolting it to the ground on the block or some bolt near the PS pump. It ran fine after that but I don't like not having the knock protection. Although while running mine bypassed on the firewall I never heard it ping as I have on other vehicles in the past. Also if you check the diagram in the FSM, you'll see the harness to the sensor is actually a shielded harness, I believe it turns into that after the green connector on the valve cover.
 

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I did the resistor mod and never looked back. Been running this for around 3 years. I just run premium gas, and take care of the fuel system.
2002 SC with 180K miles.
 

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2000 Xterra XE 4x4 3.3L AT
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I did the resistor mod and never looked back. Been running this for around 3 years. I just run premium gas, and take care of the fuel system.
2002 SC with 180K miles.
This^^

If it is being relocated to the firewall just do the resistor mod. Have one on my NA for nearly 10 years now
 

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I believe the NA trucks do use the knock sensor signal to limit timing advance, however on a SC model any DTC will put the boost bypass valve in the bypass position as well as limit timing advance. NA engines don’t worry about this because the few degrees of timing dont make that big of an impact. A couple pounds of boost lost will though
how so? the vg's havent variable timing
 

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I did the resistor mod and never looked back. Been running this for around 3 years. I just run premium gas, and take care of the fuel system.
2002 SC with 180K miles.
that was going to be my suggestion
 

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how so? the vg's havent variable timing
All engines have variable IGNITION timing. More advance starts the fire earlier so you can get a complete burn at higher RPMs. This is accomplished through mechanical advance, computer control, or both.

VG engines do not have variable VALVE timing like the VQ engines do.
 

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All engines have variable IGNITION timing. More advance starts the fire earlier so you can get a complete burn at higher RPMs. This is accomplished through mechanical advance, computer control, or both.

VG engines do not have variable VALVE timing like the VQ engines do.
Ah see i knew this but hadn't had my coffee today when i replied earlier even relized this after i had commented and thought oh man i just said something stupid lol
 

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In my understanding, the p0328 code is caused when the bias voltage is too high as opposed to p0325 which indicates knock detection. There are two wires that go to the knock sensor one that is thicker and shielded the other is a ground wire. The thicker wire will be shielded, this is the signal wire with the shield tied to ground.

The knock sensor will have a 560kilo ohm resistor that runs parallel to the knock detection circuit within it. This provides the voltage drop necessary to generate the bias voltage. The knock detection circuit develops an AC signal that runs on top of this bias voltage that the ECU interprets to detect knock. So what can go wrong
There are three components, the ECU, the wiring, and the sensor.

1)
The sensor when disconnected from the circuit should read 560 kilo ohms. If it is infinite which is typical on these sensors that means this resistor is pooched and causes the bias voltage to go high.

There is no easy way to measure this with sensor in its original mounting position on the block without also testing the pigtail that goes from the sensor to the connector beside the O2 sensor connectors. From most experiences, it's the sensor that fails not the wiring but is a possibility.

2) The wiring. With this code the bias signal has to be high so you are looking for an open circuit not a short. More importantly an open on the signal wire or ground wire.

3 The ECU. Don't wish this on anyone but if you aren't getting 5 volts at the pin for the knock sensor then it could mean a fried ECU.

I had the p0328 code and successfully did the resistor mod with noticeable improvement under hard acceleration. That meant the boost was now back as opposed to getting dumped. My 2004 SC never went into limp mode, so there may be something else happening with your vehicle.

Key measurements.
Output at ECU SB 5 volts,
BIAS voltage 2.5 volts
Sensor resistance 560 kilo ohms.

This is vague but for gen 1 Xterras these are the codes you will see for a bad knock circuit
for a 1996 to 2001 the code is a P0325
For a 2002-2004 the codes are p0327 , p0328

P0327 means bias voltage is too low
P0328 means bias voltage is too high

I would think on my 2004 P0325 indicates knock detected. I could be completely wrong.

These are the generic knock codes
  • P0325 Knock Sensor 1 Circuit (Bank 2 or Single Sensor)
  • P0326 Knock Sensor 1 Circuit Range/Performance (Bank 2 or Single Sensor)
  • P0327 Knock Sensor 1 Circuit low Input (Bank 2 or Single Sensor)
  • P0328 Knock Sensor 1 Circuit High Input (Bank 2 or Single Sensor)
  • P0329 Knock Sensor 1 Circuit Input Intermittent (Bank 2 or Single Sensor)
  • P0330 Knock Sensor 2 Circuit (Bank 2)
  • P0331 Knock Sensor 2 Circuit Range/Performance (Bank 2)
 

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Good info, I have one small correction, it's around 560k ohms you're looking for, not 360. The FSM gives a range as per the image below but most healthy sensors I have tested are in the 550-560k ohm range. I can't explain it, but while my truck ran okay with the resistor/bypass and had full boost, it definitely runs better and the fuel mileage has increased with having a proper sensor in the oem spot. I'm wonder if the ECU likes to see some variation on the signal. Or perhaps mine is an oddity or some ground got "fixed" in all the wrenching I did.

75073
 

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Your fuel economy is better with the sensor because the computer uses the data to actually adjust the ignition timing advance (as mentioned in earlier posts) as well as fuel injector spray duration and timing. The data from the various sensors (o2, knock, MAF, etc) is all used to make adjustments to maximize fuel efficiency. If one is missing then the system does what it can with incomplete, or in the case of the resistor mod, incorrect data.
The main reason for the resistor mod is to simply avoid the code and the issue of the occasional bad sensor, but not having a sensor does leave you open to engine damage and worse fuel economy. The knock sensor is there for both efficiency and as safety equipment for the engine.
 

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Fixed the 360 to 560 error in my post, thanks I was going from memory.

I can't see the ECU changing anything with respect to air-fuel or timing based on a clean/good signal from the knock sensor. I'm inclined to think the increased mileage is some extraneous result of another fix.
 

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Probably, but I didn't repair anything else at that moment. Hopefully OP got his issue resolve though. I drive my truck in all sorts of conditions (trails, long highway trips to where the gas might be not so stellar), so I want to have the knock protection there.
 
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