I have 3 check engine light codes come up 0302 / 0702 / 0703

For the 0302 I plan on cleaning out the EGR and what not.

As for the 0702 & 0703 what have been other peoples experiences? Has changing out the o2 sensors fixed the problems or is it really the cat?

I haven't felt any power loss and my mpg hasn't suffered any either. Any advise on which direction to go?

 

I know people have had this problem b/c I searched, but I haven't really seen alot of replies on what the final fix was. Anybody??

 

I have a 0702 and a knock sensor cel illumination. this pisses me off, my car is running like shiiieet i don't want to spend any more money on it. i replaced the o2 sensor with a used one and the CEL came back after a couple weeks.

 

I'm curious as hell on this if anyone has had the cat efficiency code go away after doing the rear o2, since I would like to know this for two different cars I think I'm going to start a pole since people never do follow ups.

 

i have a 07 02 code
i have a new budget y-pipe and cat
i have a brand new cat o2 sensor
i have no idea why the 07 02 code is on

I guess it ate a used right bank o2 sensor i tried to fix the problem with.

 

bump......

 

Mine is running like $hit also. It is just running too loud. I'm still getting great MPG though. I don't know whats up. I plan on cleaning the EGR this weekend and that hopefully will do away with the 0302 code.

Anyone figured out the culprit for the 0702 & 0703 codes? I plan on replacing the O2s this weekend also. I would just hate to do that and that not be the problem.

 

i have the same problem and have herd of a recall on the 96' for the O2's, egr, evap, and some other stuff but I was told by the local dealer that I needed a note from nissan in order to claim it. my light has been on with the same problem with good mileage. I am lacking in power a little tho.

 

Seems like i have a lack of power. I had the 0702 code, but now it's gone. I bought a new o2 sensor today but might return it if the code doesnt come back. I'm getting good mileage i dont know whats going on with this.

 

Well, keep us updated.

Did you reset the CEL or did it go off by itself. Every time I reset my CEL it has come back on within 50 miles or so. So I know my light isn't a fluke. If it comes back on, replace that o2 and see if that keeps the CEL off.

 

Okay I replaced the o2 sensor tonight...so we will see if the code comes back...

 

I knew this was going to happen. the 0702 and 0304 codes are back even though the o2 sensor was replaced two days ago. I don't know what to do!!!!!!!!!!!!

 

Well that sux!
Did you reset the codes even though they went off last time? Maybe you should even undo the battery for a while. I also just noticed in the post above that you also have a new cat. So that makes it even more frustrating.

 

yea a new cat thats what makes me mad. Ive replaced anything that it could be. i reset the ECU by turning that screw. if that doesnt work then i will unplug that battery!!!!!!!!!!!!!!!

i will keep you posted.

 

CEL is back on. the only thing I haven't done is keep the negative battery terminal off for a long time

 

how do i fix the 07 02 and the 0304 code? i replaced the o2sensor and they are still back!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Welcome to the club my friend. My SES light came on a few months ago with 0702 and came and went as it pleased. I had a funky KS code that would not clear but threw in a resistor and now it is gone. I still think the 0702 has something to do with it but I have a Cattman Y and Random Tech Cat with two used 02 sensors in the garage ready to go on the car. I am also doing a fed spec conversion killing both precats and eliminating the chance that the precats are causing the 0702.

Bring the car to autozone and have them clear your codes with their scanner. I had them delete the 0702 code every time but they couldnt delete the 0304 which had me puzzled (resistor changed that ).

My 0702 will come on about 100 miles or so after reseting, and last for 600-1000 then go away, then come back. It is very spurratic and inconsistent. I am really hoping that I can fix the code by putting on a y pipe with new(er) 02s.

Even though I felt a little more power from clearing the 0304, I still feel extremely sluggish. I still manage to get good gas mileage and seem to have the same symptoms as you. I am somewhat local and if you want help let me know as I am as curious about this code as you are.

Matt

 

I have a Budget Y-Pipe and a Budget Cat both are a couple months old. I might try the resistor method because your post was 100% accurate to what is happening with my car. hit me up on AIM sometime, PM me for my screen name.

 

The resistor method will only kill the 0304 code unfortunately. The thing I do not like about the 0702 code is that it is "Catalyst Efficiency Below Threshold Bank 1" which does not direct you to a specific 02 sensor. In my case it could be one of 7 things. The main cat, the 2 precats, or the 4 02 sensors. PM sent w/ AIM.

 

Have you checked how many times within 10sec interval O2 sensors switches from lean->rich? FSM states that you should replace your O2 sensors if it switches less than 5 times. Just start "Diagnostic test mode II -- self diagnostic result" and after that start your engine. The enginge should be warmed up and you should count transition from lean->reach while holding 2000rpms constantly. It starts monitoring with the left side bank, you can switch it from left to right and vice-versa with the "diagnostic mode selector". Just turn it clockwise for 2 second while enging is running. CEL will give you 2 short blinks to confirm that it is monitoring right side bank. 4 short blinks -- left side bank.

Intake air leak or insufficient fuel pressure and clogged or leaking injector may also cause "oxygene sensor" errors. And I've been told, that even air leak in the exhaust system could also trigger that error.

Update: oops, its for the front sensors, but still, intake air leaks, fuel injectors leaks, exhaust air leak can trigger 0702, 0703. You can use a multimeter to check rear sensor. Its switching ratio should be very less than ratio of the front sensors.

 

After being on for the last 2 weeks/600-700 miles, I stopped at the gas station and turned the car off w/ the SES light on for ONLY the 0702, filled up, started it up and am code free again. Talk about an inconsistant code...

 

I'll add two more cars to the list. My 99 max and my dad's 97 max both have the same problem

 

Seeing if there are any updates. My 0702 and 0703 codes haven't been on in over 2000 miles. But I am still getting the 0302 code. Still good MPG but I figured out why my car was running so loud. My fan belt broke(didn't think it had been that long since I changed it) and when I took it to the shop they replaced a pulley also and now it's back to normal, runs alot quieter. I thought it was the timing chain rattle.

 

i still have the problem...0702

 

I would check and see if the sensors are not being interferring with anything in welding area's and if there is no rust and there clear of any water contact and sever heating and check if the sensors are cleaned. GL.

 

Update: After I replaced my front header (precat) and the y pipe I needed to wait a few weeks (and still am waiting) to get the O2 simulator wired up. I am currently running with like 9 codes but the fact of the matter is that I found out the trace of my 0702. It was not the main cat that was going bad, but it was one of the O2 sensors in the y pipe (second one back on the y pipe I believe...theres 4 on a cali-spec). If you replace all of your O2 sensors and the main cat, this code should not exist but I was able to find that the problem was one of my O2 sensors. Hope this helps.

 

^^^ actually, i was the one that found that bad o2 sensor and I was removing his o2 sensor so that I could replace a bad 4-wire o2 in a taurus that was giving no o2 codes, a cat efficiency code, and had a bad o2, bad as in jingle jangle when shaken. So that's two cat efficiency codes caused by bad o2's........... and on the taurus, it was a front o2 causing the cat efficiency code.......

 

Well if i have 0702 that tells me it in one of the bank's o2. could it be the other o2?