96 pathy knock sensor location?

A forum for the legendary Nissan Pathfinder and Infiniti QX4.
SATAN
Posts: 142
Joined: Sat Jan 05, 2008 3:37 pm
Car: 1985 300zx heavily modded - 1984 Anniversary 300zx stock - 1990 Q45 stock

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So I have a knock sensor code. Bought a knock sensor. Looked for the old one on the block for like 10 minutes and just could not find it. I have heard it is a b**** to replace. On my z31 it is right next to the oil pressure sending unit on the passenger side of the block. It's not the same style sensor though.

Anyways, can someone please describe where the knock sensor is.


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Pwnin O'Brien
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Here ya go...


SATAN
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Joined: Sat Jan 05, 2008 3:37 pm
Car: 1985 300zx heavily modded - 1984 Anniversary 300zx stock - 1990 Q45 stock

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Is that why they call you Pwnin O'Brien? Cause I just got Pwned with the sensor location? LOL

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fueler
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if its of any consolation, the knock sensor code is a common one in the VG33's. It's easy to "set off", I guess.

I just reset it. I get the same code once in a blue moon, but when i erase the code it usually wont come back for a couple of years.

Cause you can see that replacing it is a royal pain in the neck.

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Pwnin O'Brien
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There's also an easy diagnostic test to see if it really is the sensor or if it is a grounding issue or something else. All you need is a digital multimeter and it might take you ten minutes to find the issue. You don't have to disassemble anything to do the test, the harness you test at is near the top of the engine.

The test procedure is on EC-177 in the engine control PDF of the FSM.

SATAN
Posts: 142
Joined: Sat Jan 05, 2008 3:37 pm
Car: 1985 300zx heavily modded - 1984 Anniversary 300zx stock - 1990 Q45 stock

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Pwnin O’Brien wrote:There's also an easy diagnostic test to see if it really is the sensor or if it is a grounding issue or something else. All you need is a digital multimeter and it might take you ten minutes to find the issue. You don't have to disassemble anything to do the test, the harness you test at is near the top of the engine.

The test procedure is on EC-177 in the engine control PDF of the FSM.
Cool thank you! I will check that out. I am assuming the harness for the knock sensor is the one that runs next along the base of the oil cap next to the O2 sensor harnesses. The one that runs toward the back side of the engine and down the fire wall. That one looks like it may run under the intake manifold toward the knock sensor...

I will check out the FSM. Buddy of mine also hinted a while back that they have faulty grounds as well...

SATAN
Posts: 142
Joined: Sat Jan 05, 2008 3:37 pm
Car: 1985 300zx heavily modded - 1984 Anniversary 300zx stock - 1990 Q45 stock

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Don't know if this pic will work for anyone but, at the tip of my index finger is the line I believe to be the one going to the knock sensor. Can anyone confirm?


Towerdog
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Joined: Wed Aug 10, 2011 11:05 am

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It is in that wire housing, however it is further back. Follow that and it will continue after splitting off to the last injector if you unwrap the back covering its a single white wire.

I just replaced the knock sensor and it was not the most fun day in my life. You should drain some of the coolant from the block, as this made it not so messy. After removing all the hoses and connectors from the top intake, I just set it aside to the left. Note: this part sucks! There two hoses on the back with c-clips that are very hard to get to. there are also two electrical connections on the back right on the underside that need to be unplugged. I just tipped the front up to unhook these. Once this part is over with, have a beer and pat yourself on the back. Next take the fuel rail off with the four hex bolts and I also set that to the left without having to open the system, this was nice! there are plastic spacers under the rails, and rubber rings that the injectors sit into so don't loose them. Lastly to take off the lower intake there are 6, yes 6 bolts holding it onto the block. 5 hex on top that are easy enough to get off, remember to torque them back to spec. as its in inch lbs. The last one was sneaky and it sits in the front of the engine horizontal. I took off the front top serpentine belt tension bracket and all to access this Phillips head bolt. After this your in the clear, you can take the hoses off the back part of the lower intake pull it up over the bolt studs and see the knock sensor. I bought my sensor for 27 bucks online inc. shipping and with new gaskets lower and upper all for around 50 bucks its a lot more work than money. It runs great with no check engine light now my back is hurting.

Fixurrideclyde
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Joined: Tue Jun 04, 2013 7:05 pm
Car: '02 nissan pathfinder 3.3l v6

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Let me just say this procedure is a long process, get ready. The late 90s early 2000 pathfinder knock sensor is located directly on top of the engine block towards the back of the engine, which means its beneath the entire intake manifold. Did one of these just the other week. I started by disconnecting the positive battery terminal and then removing all the intake hoses and sensors that are visibly connected to the manifold. The next step is taking out the throttle body( don't get your cables mixed up). Next your remove the distributor cap and all plug wires running to spark plugs in the Manifold. Next you must disconnect the EGR valve and be careful not to lose the small bracket that's attached to the bolts on the back of it. Next you will unscrew the 5 bolts on top of the manifold and remove the 2sensors underneath it, then carefully remove the top part of the manifold. This is only the top part of it. Most likely your top bolts and allen heads so spraying a little on pb blaster on them and waiting for a few mins is wise as they strip very easily.

Once the top part is off, your next step is to remove the fuel line and all sensors connected to it. Disconnect the hose that's on the back of the line and set it to the side. Next you must remove the 2 bolts between the top radiator line and the front of the lower manifold. This is very difficult as there is very little room to work. A swivel head socket and an opened ended wrench got me there, but I also had to remove the distributor completely in order to get any torque to the right hand side bolt. You must be very careful and remember to mark your distributors exact location before disconnecting. Next you remove all bolts from the lower manifold and remove it. You will lose quite a bit if coolant so it is wise to place something underneath the vehicle if you don't plan on bleeding the coolant entirely first. Once it's off the sensor will be exposed. Remove and replace it.

You can do an ohms test on the sensor by putting the positive terminal of a volt meter the continuity slot inside the sensor and the negative terminal to a metal ground and a working sensor conducts around 700 ohms. But good or bad, by the time you've done all this work you should just replace it regardless. I got one for 40 bucks at my local auto parts store. Be sure to resilicone the gaskets if they're in good shape. If not they're relatively inexpensive to buy. Also, beware of certain things on the Internet that suggest moving and placing the sensor in a new place on the engine. The sensor detects irregularities in your cylinders and its location is ideal for accurate reading to send to your PCM.

Assembly is the reverse of the dissembley. Good luck to you man. Any questions just ask.

Brute 03
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Joined: Wed Sep 12, 2012 5:44 pm
Car: 2003 Nissan Pathfinder
2003 Ford Mustang GT

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I also need to replace my knock sensor. Please tell me its easier on the 3.5L

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Towncivilian
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It isn't. It's buried under the upper and lower intake manifolds and IIRC the fuel rail must come off as well.


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