This is how to remove and replace a Knock Sensor on a 1995 Maxima (95-99)

You can get a knock sensor off of ebay for about $40-$70 (Or LESS)
2012 Update: You can get a knock sensor for less than $20, they even sell them on amazon if you don't like ebay.

Pep Boys wanted to charge me $207.89 for a knock sensor, and $263.90 to remove and replace it. ($470!!)

That's a savings of $400 for a self installation. (Could be more or less depending on the shop)

So lets get started.

All that you will really need for this is:

1. The replacement knock sensor
2. 12mm wrench
3. Flashlight
4. Patience
5. Gloves
6. Flat head screwdriver, or needle nosepliers (to remove harness clip)

Its a pain in the *** and you will most likely bleed, especially if you have large hands. It took me about 15-20 minutes to do. The hardest part is squeezing the little wrench in the crevice and trying to loosen the one bolt. Once its loose though, it shouldn't take you more then 5 minutes to put the new one in.

1. What you need.

2. Knock Sensor Location






3. Unbolt the knock sensor with your 12mm wrench. *Hardest part, I actually got a hammer and pulled it against the wrench as a lever to get the bolt loose. Be patient, once its finally loose you can unbolt it with your finger.

 

4. Take knock sensor with the harness and put it on a flat surface. (On the Engine)




5. Inspect the knock sensor for damage/corrosion.



Woah this bad boy needs to be replaced. Look at that crack down the middle.

 

6. With needle nose pliers or a flathead slide the metal clip on the harness up. Don't take it off though



7.
Attach the replacement knock sensor in the harness and slide the clip down to secure it.

8. Be careful not to drop knock sensor when manuevering through the crevice. Screw in the bolt by hand. And tighten it slightly.



Job done.

You just saved yourself hundreds of dollars, and a few hours of manual labor.

 

The n00bs should appreciate this. Nice writeup SPER.

 

hey, i appreciate it....does this make me a noob???

 

I'm still a noob, I've learned alot about my maxima though over the past couple months. Before I had this car I never even heard of a knock sensor.

 

That's the same way I did, 12mm wrench and a screwdriver to pry with. Tons easier than a ratchet, extensions, and swivels (IMO).

 

Really? Many cars now have them.

For a quick rundown, eBay is the easiest to see the majority: http://shop.ebay.com/items/_W0QQ_nkw...Q_fromZQQ_mdoZ

Though you'll notice that over half of them are for Nissans, heh.

 

Wow $25 shipped for a knock sensor.. I feel like i got ripped off now lol, didn't know you could get one for so cheap.

 

^^
Thats mass production for you

 

Thanks for posting the pics!

This definitely would've been more useful for me last week, but I got it done anyway with the help of my friend's small hands.

I ordered the generic knock sensor from eBay for ~$25 shipped and it worked like a charm!

 

Pardon my noobness,
but how do you know if your knock sensor is due for a change?
visual inspection?
check engin light?
symptoms?

I just got a max so im not too familiar with all that stuff
thanks guys

 

my check engine light is on, thats how i know

 

The KS code will NOT light the CEL.

You'll get a code for it, generally.

 

This may be a dumb question, but how does the knock sensor code not light the check engine light? Are there any other codes that won't illuminate the light? I believe you though because I just had the CEL come on in my 96 and pulled the codes and there were two, one for the KS and one for an O2, and I highly doubt they went out on the same day.

 

How does it not? It just...doesn't. The ECU doesn't light the MIL for that code, simple as that.

Replace the O2, clear the codes, then check again. The KS code seems to be thrown by emissions DTCs.

 

knock sensor is a ghost code, your O2 sensor could have set off the knock sensor. There are other ghost codes that are known. Another common one seem to be the evap. Don't know why the knock sensor won't light a code, but it doesn't. But if you sense a loss in power, you might want to check for a code. But other than that, it doesn't do any harm to your car.

edit***damn, pmohr can type faster than me and i thought that i can type fast....

 

That's strange. I understand how a faulty emissions sensor could set a KS code. But I'm more familiar with GM's and a KS fault alone will definitely give you a CEL in one of their vehicles. You learn something new everyday I guess.

Just out of curiosity, do you fellas know of any other ghost codes that won't give a CEL?

 

about the easy way to change the KS, wat i did was take the IM off, its not that hard...

 

I changed mine for about 4-5 min. I am sure you can't do it faster with taking the manifold off

 

ah ok,
thanks for the response guys,

great tutorial btw,
will come in handy

 

i kno this isnt the point of the thread but jsut a quick comment...

i got a CEL for EVAP and KS only.. The EVAP could be my gas cap but im not really sure ( if that makes ne difference).

 

NICE WRITE UP!

 

good write up helpfull

 

where was this tutorial last year when i needed it for my purple 96.
the current 96 already had it done along with the water pump
of course current 96 has an uncertain future right now.

 

this is ofcoarse the fed-spec.

 

The cali got a different KS?

 

It's the same KS, just harder to get to.

 

This is great, thanks man.

Do you remember when the knock sensor went out? Did it make your car hesitate and then die? And then when you turned the car back on, did the check engine light come on?

Thats what happened to my car yesterday night.... This morning the car drives but with the check engine light on... So I unplugged the knock sensor to see if that made a difference, which it didn't.... which leads me to believe its time to replace it.

Do those "fuel injector additives" cause any damage to the knock sensor? I just put some in 5 days ago and this happens.

 

A KS will not cause the engine to stall. Simple as that.

Have you not pulled the codes? A KS code will not light the CEL.

 

Knock sensor is not causing your problems. And did you even bother to check your code(s)?? KS doesn't trigger a CEL btw.

Your method of diagnosing your problem is not methodical.

Fuel injector additives will do nothing to your KS. You're talking apples and oranges here bro.

EDIT: Pmohr beat me to it.

 

Yeah the codes that came up were 1) MAF sensor and 2) Knock sensor.
I just installed some NGK Platnium G-Power plugs 3 days ago and am wondering if thats what caused this. These NGK platnium plugs were only $3 compared to the other NGK (stock plugs) for $11..... What the hell are the G-Power plugs? Im going to put the factory plugs back in and see if anything changes... if it does, make a sticky to AVOID the NGK G-Power Platniums ( read in another thread that the G-power plugs did the same thing to someone elses maxima)

 

It's not the spark plugs either....it's clearly your MAF. Chances are, the KS is piggybacking the MAF code, thus throwing a false KS code. Fix the MAF problem, and I bet both codes will go away.

 

I agree... I wasted more time with the extentions and u-joints than just cramming a 12mm wrench in the blackhole and using a screwdriver on the open end for leverage...

 

Is there a place we can re-locate it to ? (like this 300zx) http://www.youtube.com/watch?v=EZoOcHtv-LI

 

...why would you want to? Move it anywhere but where it was from the factory, and you're likely going to end up with a lot less sensitivity to knock. Might as well just throw a resistor in the harness, IMO.

Did you search? A few people have relocated it, and there have been several threads on it.

 

I got in there no problem

Remember, to be an import mechanic you also have to be a contortionist.

 

about the easiest way to take out a KS, i've done numerous times and I have baseball gloves for hands.

 

pmohr, funny you mention the resistor thing, I was going to do that exact thing on my daughters 97 Altima until I can get a new KS. Have you seen this done and do you remember the value used? I seem to remember that it's somewhere in the 600K region.

 

I took your contortionist advice and bent that green sensor back out of frustration.. now my hand fits in there just fine