# Engine Code P0325 - Knock Sensor Failure



## bbpatt (Jul 20, 2005)

I have a 1995 Maxima GXE that has the "check engine" light on. I had a diagnostic run and the code came back P0325 - Knock Sensor Failure. The estimate for repair is $630 (including the $95 diagnostic charge).

The light came on over 5 weeks ago. Before I could get it in to the shop to have it looked at, the entire electrical system shut down while driving. Fortunately, I was able to pull off the road and it (the system) recharged enough to get me to Sears Auto Center. I wound up having both the battery and alternator replaced by Sears (the battery was still under warranty, so that was free.) The cost of repairs was over $400. 

When I got the car back, the check engine light stayed off for a week. Now that its back on, I am looking at another $600 for repairs.

What is going on with this car? It has only 75,000 miles on it. What will happen if I don't have this repaired right away?

I appreciate any help and insight!!!


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## MaxQuest (Sep 11, 2004)

Are there any other codes. The knock sensor code does not throw a check engine light. 
You might have other things wrong with your car. 
As for the knock sensor, change it yourself. The part cost about $100. 
Here are a couple of sites that show how to change the knock sensor
http://www.skippynet.com/maxima/knocksensor.htm http://www.motorvate.ca/mvp.php/507


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## bbpatt (Jul 20, 2005)

*Spark Plugs?*

Is it possible the spark plugs have gone bad? Another shop that looked at it said they thought the engine needed a tune-up and replace the plugs, wires, fuel filter, etc.

And, no....there were no other codes provided as coming up on the diagnostic. 




MaxQuest said:


> Are there any other codes. The knock sensor code does not throw a check engine light.
> You might have other things wrong with your car.
> As for the knock sensor, change it yourself. The part cost about $100.
> Here are a couple of sites that show how to change the knock sensor
> http://www.skippynet.com/maxima/knocksensor.htm http://www.motorvate.ca/mvp.php/507


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## MaxQuest (Sep 11, 2004)

bbpatt said:


> Is it possible the spark plugs have gone bad? Another shop that looked at it said they thought the engine needed a tune-up and replace the plugs, wires, fuel filter, etc.
> 
> And, no....there were no other codes provided as coming up on the diagnostic.



What wire did they replace? Your car does not have spark plug wires to replace. If your check engine light is on then you should have more then the Knock sensor code. A bad knock sensor does not trigger the light, it just stores the code on the ECU.


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## DRUNKHORSE (Mar 6, 2005)

if ur whole electrical system shut down on u that only means that its ur alternator usually, and since u had it replaced, i dont think u have to worry much about the knock code. if the car seems fine drive it around another week or 2. maybe later the car will give off a different code that usually makes the knock sensor code come up.


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## bbpatt (Jul 20, 2005)

*Any harm driving it?*

With the knock sensor code showing through the diagnostic, and from what I am reading in these posts, the engine light is likely another separate problem, is it safe to continue driving as is? Is it okay to drive with a bad knock sensor?

The car appears to run fine (as far as I can tell).....it has been over two weeks with the check engine light on.

The engine light, according to the owners manual, may be emissions related. Does anyone have any experience with emissions sensors or other concerns when this light comes on?

I appreciate all your help!!!


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## DRUNKHORSE (Mar 6, 2005)

ok, if i were u, I would disconnect the battery/ or erase the codes. personally i would just disconnect the battery. Then hope that it doesnt come back on. If it doesnt, then ur fine, but if it does and its the knock sensor, replace it. hint *(replace it urself its very easy)*if dont know how to, look around i know there is a thread about it. 

what did u want to know about emissions sensors?

if u wanna learn about sensors go to the link, and find what sensor u want to learn about.

http://autozone.com/servlet/UiBroke..._us/0900823d/80/05/03/48/0900823d80050348.jsp


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## SOUPBONE (Aug 3, 2005)

*knock sensor failure*



bbpatt said:


> I have a 1995 Maxima GXE that has the "check engine" light on. I had a diagnostic run and the code came back P0325 - Knock Sensor Failure. The estimate for repair is $630 (including the $95 diagnostic charge).
> 
> The light came on over 5 weeks ago. Before I could get it in to the shop to have it looked at, the entire electrical system shut down while driving. Fortunately, I was able to pull off the road and it (the system) recharged enough to get me to Sears Auto Center. I wound up having both the battery and alternator replaced by Sears (the battery was still under warranty, so that was free.) The cost of repairs was over $400.
> 
> ...


I work at a nissan dealership and this code comes up at times. As other posters have noted this code fdoes not tigger the ses light. On those that do show this code we have found that the knock sensor is failed.If you use premium fuel as recommended there is no advers effect (i own a 97 i30 with the kock sensor failure and i do use premium fuel and have put on 75k miles with no advers effect). if you use regular unleaded and the engine develops a ping the pcm will not be able to retard the spark timing and henceforth engine damage may occur


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## MaxQuest (Sep 11, 2004)

I thought if you have a bad knock sensor, the computer will only run in the retard timing mode. This is why there is lost of power and gas mileage with a bad kncok sensor.


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## bbpatt (Jul 20, 2005)

Thanks for the info.....I do not use premium fuel for the vehicle. However, it looks like I need to start right away using it.

Interestingly....the "check engine" light that had come on for the second time, has now gone off again. The car seems to run fine as far as I can tell, but it does seem a bit off.


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## julyguy (Jun 24, 2005)

*Surprised!*

I have a 96 Maxima GLE with over 182K km on it and I've also been experiencing the same problem since May 05. 

Other than this, the car's been virtually problem free except for normal wear items such as tires and brakes. It still has it's original exhaust system.

I did have the knock sensor replaced which was expensive (> $700 Cdn) and the problem went away for about 2 weeks. The light then came back on for another week and again went off. It has now come back on. At all times, I didn't have any driveability problems or excess fuel usage.

From what I've read here, it could be may be related to problems in the wiring harness due to the car's age. It's been suggested that it could be caused by corrosion problems at the wire connectors. 

I'm going to have it checked and I'll share what I find out.

Also, I've always used premium gas and, despite the current $1.10 per liter cost here, will continue to do so.


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## brianw (Feb 25, 2004)

$600 to replace the knock sensor?

http://www.motorvate.ca/mvp.php/507


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## levg79 (Aug 17, 2005)

It is a very common problem with the Maxima's diagnostic that a Knock Sensor code comes up. However, in about 90% of the cases, it has nothing to do with the Knock sensor. Most of the time it's the O2 sensor that sends the code.

Also Maximas are made to run on regular unleaded gas, so using it will not harm the car in any way.


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## BigGreg85 (Jun 30, 2005)

levg79 said:


> It is a very common problem with the Maxima's diagnostic that a Knock Sensor code comes up. However, in about 90% of the cases, it has nothing to do with the Knock sensor. Most of the time it's the O2 sensor that sends the code.
> 
> Also Maximas are made to run on regular unleaded gas, so using it will not harm the car in any way.


in my manual it says to use a fuel with an octane level no less than 91


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## bbpatt (Jul 20, 2005)

*Fuel....*

I replaced the plugs a few weeks ago....they were very bad. The vehicle ran well for a few days, but it is still "pinging" or shaking when idle. 

Also, the "check engine" light has come on again. I am going to try to replace the knock sensor and then replace the O2 sensor as well.

With gas prices over $3.30 a gallon for reg unleaded, I cannot afford to keep putting in premium fuel.


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## jona (Nov 20, 2009)

bbpatt said:


> I replaced the plugs a few weeks ago....they were very bad. The vehicle ran well for a few days, but it is still "pinging" or shaking when idle.
> 
> Also, the "check engine" light has come on again. I am going to try to replace the knock sensor and then replace the O2 sensor as well.
> 
> With gas prices over $3.30 a gallon for reg unleaded, I cannot afford to keep putting in premium fuel.


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hi, did you fix the problem. i got same thing happen in my 1994 nissan maxima,the check engine light come on when i am driving on free way, but when i get on city engine light turn off. they said may be knock sensor failed. it will cost me more than $300 to replace it.


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## TraumaCase284 (Mar 26, 2012)

bbpatt said:


> With the knock sensor code showing through the diagnostic, and from what I am reading in these posts, the engine light is likely another separate problem, is it safe to continue driving as is? Is it okay to drive with a bad knock sensor?
> 
> The car appears to run fine (as far as I can tell).....it has been over two weeks with the check engine light on.
> 
> ...


MY 97 maxima GLE has the same code as yours p0325. But it also has code p1400. and a different mechanic also says o2 sensor... only problem... we dont know whic o2 sensor the second opinion at o'riely's didnt have an o2 sensor code. jsut the knock and EGR so i'm torn on replacing the EGR or trying to find the right o2 sensor


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## 95maxstepdad (Jun 26, 2009)

well, i got a 95max with 213k miles and its got all three codes p0325 is listed first and it has the note MIL in small letters, then a p0146 o2 (and i think its generally the upsteam one -the ds is used to measure can effic i think) and then the p1400. Its never had a ks replaced. thats first on the list nc its easiest on the wallet.


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## 95maxstepdad (Jun 26, 2009)

And, I just found one on ebay for 7.78. Pretty good price below rockauto even which is upper 50s-low60s


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## cngarch (Sep 5, 2018)

Get yourself a multi meter and get on utube and type in checking knock sensor on your car. they do go bad but with small hands an a lot of cuts (the gaskets are stainless steel and will cut you) they can be replaced without taking the intake manifold off the engine($600.00).

Otherwise have the fuel pressure checked. On these older cars the fuel pump can trigger the knock sensor code. I have a 1996 infinity with 268000 miles and it runs fine but does have problems with vacuum leaks which can cause a lot of problems. misfiling, poor gas mileage, pcv valve codes. Diagnosis in 1996 was in it infancy and OBT2 codes were also. The problem is often far from what it says.

I have also had to take the intake manifold off to replace the valve cover gasket. A common problem. I have had the transmission fluid replaced every 75000 miles. (synthetic)


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