Geophrum

Car has had the CEL on for almost a year now because of bad O2 sensors in the front. so i had to get the car inspected and they failed it because the 02s. both front o2s and the knock sensor were throwing codes.. ok.. so i replaced the o2 sensors in the y pipe.. and went to change the knock but the cable is crap.. some one who owned the car before me had duct tape wraped around the Knock and the plug.. when i took the tape off, the plug was broken and it looked like the wrong Knock sensor. the connector was rounded were it plugs in instead of square. (not sure if that makes sense to you) i will have to find a new wire harness for it..

that being said after jimmy riging the Knock sensor and replacing the o2 i cleared the codes again and drove it for a few days.. brought it back and the reader they are using said the evap wasnt ready and to come back later... ok no problem.. i asked if the 02 and Knock passed and he said yes, but they want to make sure on everything befor they give me a sticker.. (Bastards) they are running the tests for free anyways....

the next day i drove the car to work (1/2 hour drive) parked went to work.. came out at the end of the day started her up and bam.. CEL... I ran the codes and 0304 0510 and 0512... Knock sensor and the rear o2 and unknown?

now for the questions..
0304 - Does any one know were to get the Knock sensor wire.

0510 - wouldn't that o2 show up on the previous scans? i mean if it was bad.. why would it show up now and not befor i replaced the others or after when i brought it back

0512 - code does not show up any were but after searching it seems like the same rear o2 sensor having a voltage problem.. can any one correct me if i am wrong?

Any help.. i have a temp sticker on the car that gives me 60 days to get it fixed..

Damn NH for changing there inspection laws

Thanks in advance

ROCKART

iTrader: (23)

the knock sensor harness is like 15 bux from courtesy nissan. probably even cheaper from south pointe nissan.

and i dont know from experience, but from reading in here over the past months ive heard people say that when one 02 sensor fails, usually the others are not far behind (due to the extra load caused by one failing)

maxx0831

iTrader: (2)

How many o2 sensors does the 4th gen have?

KRRZ350

iTrader: (29)

3, two pre-cat used for engine control and one post-cat to moniter the cat.

As for the knock sensor code, considering you seem a little on the cheap side (if you replaced your o2's a year ago you would have made that back in gas probably) I'm geussing you run 87? That WILL cause a knock sensor code! So you should test the knock-sensor resistance (this advice is ignoring your weird situation) clear wire on the sub harness & ground should be 500-620k ohms.

Geophrum

yes 3 i replaced the 2 on the down pipes in the y pipe.. the entire exhaust except the cat and the o2 sensors were replaced last year.. so now the only 2 items left to replace are the cat and the rear o2

I know your trying to help... and thank you... and dont take this the wrong way, but... Im not a Noob... granted i dont have as meny posts on the forum as most but i this is my 2nd max.. i have been here for a while.... I know what causes the knock sensor code...

I am not actually on the cheap side.. loosing my job in the begining of the year and having to take lower paying jobs to support my wife and 2 kids is why i waited so long.. trying to come up with $150+ for knock sensor and $100+ each for o2 sensors were not an option at the time.. granted i found the sensors Alot cheaper. and no i have never put less than 91 in my maxima.. and usually always Sunoco 93 as that is the gas station closest to me. i consider the price of gas (as high as it is) a cost of living. no matter how high it gets you need it to get from point A to point B.

I will look into the ohms.. but i know that i need a new wire harness, as the one that is there has been broken to fit a Knock sensor that should not of gone on the car... the question was were can i find the wire Harness. i asked because i found several places selling the Knock sensor kit which includes the harness and the sensor.. i was hopeing for just the harness

and the question for the o2 is why it just now threw a code when the past 4-5 times i checked the codes and the garage checked the codes did it not come up.. i find it weird that about a week after the front 2 o2s were replaced that this one would fail.. all 3 o2 sensors bad?? or would there be something else that may of contributed??

jvckustumz

iTrader: (1)

maybe the o2's were bad to begin with, new parts aren't always perfect thats why they have warranties, i would take them back out and exchange them for new ones,it shouldn't cost anything b/c of the warranty, where did you get them from?

Geophrum

i would agree with that, but, the new ones i put in are not the ones causing the error. it is the one i havent replaced yet that wasnt throwing codes before.

before i replaced the 02 sensors i was getting 3 codes and that was it.. knock and i dont remember the exact codes but they were the front o2 sensors.. so i replaced them.. those codes went away... except the knock sensor... and now i am getting the 0510 and 0512.. 2 different codes along with the knock..

does our ECU only display 3 codes at a time?

this is why i am wondering if there may be something else wrong..

I am going to chock the Knock sensor up to bad wireharness and call that one done.. just need to find a new one..