I have the knock sensor code on my max. The dealer said that if there is no other codes with the knock sensor code then everything is fine. He said that he has flat refused to change them on other cars before because there were no other codes with it. He says that the code (03 04) indicates that it is working fine and it is probably set off by some vibration or whatever. As a matter of fact he claims that after I change the KS the code will come back after I run it hard once. This is really starting to **** me off. Has anyone else heard this from a nissan dealer?

 

I was getting the KS code with no other codes and I changed mine and felt an immediated diff....I dont know what that guy is talking about because that is the whole point of the code...to tell you it is not working properly

 

I don't know what he is talking about either. I believe that I have a partially working KS and I want consistent performance so I will probably change it anyway. But for a dealer to say this makes me wonder if I am wasting my time and 100 bucks to do this if the code will come back again later. He claims that it will come back after the new one is in and mine is probably working properly. Has this happened to anyone else or does the code go for good once you install the new one?

 

At least the dealer can do before saying anything is testing the KS on your car. If he didn't, I don't know if he knows exactly what he is talking about. Just because it doesnt' trigger a CEL that doesn't mean a problem doesn't exist

 

maybe he assumed you used really crappy gasoline???? he sounds like he doesnt have a clue!!!!!

 

I would take it to a (non-dealer) mechanic. It will be cheaper to fix anyways, that is if you don't want to do it yourself.

 

ya have it replaced asap. only run premium fuel in ur tank. and if they say they have to remove the intake manifold, then take the car somewhere else because you dont need to. they charge extra. stealerships suck

 

what if you don't replace it? is it going to hurt anything else?

Serge

 

Performance. It'll be like replacing your VQ with an I4 Honda engine; no hp, no tq, no power, nada.

~THT

 

Really, the only time to replace a KS if it comes up 03 04 AND no other codes. The dealer is full of it! Definitely try doing it yourself--not that hard. What's regaining the lost 15% power worth to you?

 

wow...pretty much everything the dealership told you is flat out wrong.

Read the FAQ and DIY's on it and do it yourself. Lame.

 

Just another point of view: When I first got my 95 max I used 87. After a while I got the knock sensor code. Then I started using 93 octane and reset the ecu and 100,000k later I haven't got a knock sensor code. I consistently get between 425-450 miles per gallon highway. Point being, nothing awful will happen if you don't replace it. However, I will say that in first gear I think I feel a slight hesitation when I step on the gas. From all the 0304 posts I read, this goes away if you replace the sensor and you get that "feeling of power" back........

 

yeah i had two different nissan dealers tell me that my cars ks didnt need replaced even though it was throwing the code. the first dealer told me that it was because I wasnt using premium fuel.. the second dealer actually had me speak with the head mechanic who has worked for the dealer for 12 years... he said that he sees tons of cars come in that throw the ks code but the average consumer doesnt know cause it doesnt trigger the cel so they dont do anything about it. This mechanic told me the same thing they told you.. if I did change the sensor the code would come back.. he reccomended to leave it go cause it wasnt affecting the driveability of the car. I didnt believe him.. I changed the sensor out and have been driving the car for 3 months and havent gotten the code since. i dont know whats up with these nissan dealers!

 

I talked to my regular mechanic and he thinks that he can get to it without removing the manifold. This way he would charge less than an hour in labor. I am pretty sure that I can do it myself but I do not have the tools that I need to do it. So basically it may be worth it to just have them do it because I would have to go buy some tools anyway.
The dealer is smoking something obviously. Maybe he thought that I wouldn't care about the performance aspect of the car, but I do. I even told him that I use 91 octane and the previous owner did too.
I did see another thread where someone posted a claim that the sensor rarely goes bad and it is mostly picking up on some other issue with the engine. I will buy the part anyway and see if the code goes away for good.

 

Did you notice more power and better gas mileage yet? I get 25mpg or so but it is mostly highway driving. That is still close to normal I think.

 

Alrite guys i have a ques. my cel came up with the knock sensor code 0304, and i also have a idle speed code and an auto tranny comp signal to ecu code come on, do i have to change my knock sensor? i also felt a lack of power for the past 3 weeks now

 

You dont have to remove the manifold to change the knock sensor, it would be easier but I dont think anyone has ever gone that far to just change the knock sensor. I wouldnt listen to the dealership, I went there when I was having problems with shifting into 3rd gear and they told me that I just have to flush my tranny and the TORQUE CONVERTER because there is build up there.

 

TC in a manual! ha ha...

The only tools needed for a KS change are a set of sockets and a ratchet...maybe a bar of some sort. I had to use an extention to break the KS bolt loose. I wedged it between the block and ratchet (to turn the ratchet). It never hurts to try.......well maybe you'll bleed a bit!

 

Well in states like California, if the code is set you'll fail emissions. So it's not something you can ignore forever. I bought my 95 SE out of state and it had the knock sensor code. I checked it before I even attempted to smog the car. I cleared it and it came back almost immediately. I replaced the sensor and the subharness in under 15 minutes. Passed emissions and still no returned code.

I also noticed an increase in power, especially in 2nd gear below 3500rpms (I have a manual).

When you talk with someone at a dealership, you'll usually get a Service Advisor. Most of these guys are clueless and sometimes turn out to be big liars. There are exceptions to this at a good dealership where the people are trained and want to make the customer happy. However they'll tell you whatever they feel like because the general consumer visiting the dealership has no automotive experience. I've asked questions I knew the answer to just to see what type of answer I would get. Sometimes it's hard not to laugh at them. I even had one tell me "Brakes are not a safety item". So use your BS meter when talking with these guys.

My buddy just bought a 96 SE, same deal. His code also came back right away and he failed emissions. He replaced the KS, drove around and passed with no problems. The code has not returned either. YMMV.

 

Im pretty sure my knock sensor was damaged for a long time. I never got any engine light codes for the 2 months that I h ad the car but then one day i was driving for lunch and got a engine light. Got two codes one was the neutral switch and the other was the knock sensor. When I changed out the knock sensor it had been damaged for a while. And when I talked to the dealershuip about it they said theres always a code that accompanies the knocksensor code. My knock sesnor was cracked and had rust in it so Im think at least a year it was down. So i think there might be some truth in it bring up a second code.. But I also had a problem trying to explain my knock sensor was broken after I replaced it just to see what he would say. He also refused that the KS was the problem. I told him it was cracked in half.. he said it had to have been hit hard then.. I was like riiiiight where its located... okay buddy... I think it was just over tightened. Just my 2 cents tho. But Id go and replace it.

 

i lost about 4mpg and noticed a huge loss in power when mine went bad. You can double check it with an ohm meter to see if it is truly bad. the resistance should be very high, but not open circuit