# 1998 altima knock sensor?



## sgt795 (Sep 6, 2006)

Autozone says my service light trouble codes are for a bad rear O2 sensor and a bad
knock sensor. Is it odd that both of these sensors failed at the same time or is there something else going on with the error codes?

I changed out the rear O2 sensor as it wasn't that much $$$ or too difficult, the knock sensor is another story. 
Where is the knock sensor on the 98 Altima?

I tried resetting the trouble codes by disconnecting the neg battery terminal but still have a service engine light. Hopefully when I go back to Autozone the O2 sensor code will be gone. 

Any thoughts on the combination of these 2 codes showing up together at the same time?
Is the knock sensor tough to change?

Thanks


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## Darktide (Jul 29, 2004)

both of them going off at the same time isn't surprising. You've done the right thing so don't worry. Just have your codes cleared and you should be just fine. Disconnecting the negative battery cable probably won't do the trick to clear it. If you do a search on clearing ECM codes there are a few threads that will help you with that. I've never had to do it myself so I don't remember the specifics. All I remember is that the computer is under the kick panel by the gas pedal and there is a screw that you need to turn (and be gentle with it). 

Here ya go, I found the post.



Londonderry said:


> with the car on but not running
> remove the small lower access panel on the right side of the gas pedal, you might have to move the seat all the way back to get at it. See the computer, its a small metal box. Now with a flash light and a small standard screw driver, you'll see a screw on the side of the computer. Turn it clockwise and then quickly back to counter clock wise. That will clear the codes. If it doesn't work try it again



I hope that helps you out. Autozone provides their service for free but it saves you the drive. Also, when you do this chances are the SES light will probably blink. Its actually blinking a code for you to tell you what codes its throwing, it should also clear the codes. Good luck with it and keep us posted.


Darktide


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## sgt795 (Sep 6, 2006)

Darktide said:


> both of them going off at the same time isn't surprising. You've done the right thing so don't worry. Just have your codes cleared and you should be just fine. Disconnecting the negative battery cable probably won't do the trick to clear it. If you do a search on clearing ECM codes there are a few threads that will help you with that. I've never had to do it myself so I don't remember the specifics. All I remember is that the computer is under the kick panel by the gas pedal and there is a screw that you need to turn (and be gentle with it).
> 
> Here ya go, I found the post.
> 
> ...


Darktide

Thanks for the info, it has been very helpful and the light is now off.
Your assistance is very much appreciated

Dave/sgt795


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