# O2 woes on 07 sentra



## Pos ses (7 mo ago)

Took the car to MANY different stores to have the diagnostic tool analyze what ails this thing. ALL of them said it was either a bad gas cap, O2 sensors or catalytic converter. Well, after changing ALL piece by piece, that blasted SES light STILL shines bold and bright. I've lost my patience and a ton of cash chasing after this mandatory headache to zero results. I've put a new catalytic converter on it, down & upstream sensors, intake gasket, pcv valve, spark plugs, cleaned the throttle body, and about $100 worth of "additives", etc... the fool thing runs like a million bucks! Just that lousy light won't go out. Got inspection coming next month. Been at this now for 7 weeks (ordering packages and waiting, & puttingparts on on my one day off. I requested 2 in a row yesterday and today. Don't get too many of those. Lost my MOJO and will yesterday to do any more to it after a futile attempt to shut the light off). Got one more month of having a sick pit in my stomach yet to go. What is left? What can I do now????? 
H E L P !!!!!!!!!!
P.S. Oh, one thing to note: I changed the upstream sensor yesterday. The plug ins seemed to align, but the plastic connector looks like the slide in guides are misplaced by a couple mm. Had to sand the slides down to fit, and it plugged in together fine. While running it, I unplugged the connector and engine began to stumble, then ran fine after reattaching it. Working?
What next? How much more anxiety must I endure?
TNX.


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## Pos ses (7 mo ago)

Only one code shows: 420 (I thought that was a GOOD thing!!! Lol)


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## Pos ses (7 mo ago)

Pos ses said:


> Took the car to MANY different stores to have the diagnostic tool analyze what ails this thing. ALL of them said it was either a bad gas cap, O2 sensors or catalytic converter. Well, after changing ALL piece by piece, that blasted SES light STILL shines bold and bright. I've lost my patience and a ton of cash chasing after this mandatory headache to zero results. I've put a new catalytic converter on it, down & upstream sensors, intake gasket, pcv valve, spark plugs, cleaned the throttle body, and about $100 worth of "additives", etc... the fool thing runs like a million bucks! Just that lousy light won't go out. Got inspection coming next month. Been at this now for 7 weeks (ordering packages and waiting, & puttingparts on on my one day off. I requested 2 in a row yesterday and today. Don't get too many of those. Lost my MOJO and will yesterday to do any more to it after a futile attempt to shut the light off). Got one more month of having a sick pit in my stomach yet to go. What is left? What can I do now?????
> H E L P !!!!!!!!!!
> P.S. Oh, one thing to note: I changed the upstream sensor yesterday. The plug ins seemed to align, but the plastic connector looks like the slide in guides are misplaced by a couple mm. Had to sand the slides down to fit, and it plugged in together fine. While running it, I unplugged the connector and engine began to stumble, then ran fine after reattaching it. Working?
> What next? How much more anxiety must I endure?
> TNX.


Only one code: 420. (Eye roll)


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## VStar650CL (Nov 12, 2020)

P0420 is a dead-cat code. Bad O2 sensors won't cause it, although aftermarket sensors or aftermarket cats sometimes do. Small exhaust leaks anyplace between the A/F (front O2) and the rear HO2S can fool the system. If your rear O2 is OEM and you don't find any leaks, your cat is shot.


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## Pos ses (7 mo ago)

BRAND NEW CAT & piping! Brand new up & downstream 02 sensors. NEW exhaust donuts. The front sensor was visibly bad. You can BARELY hear the car run, standing right next to it. NO leaks! Smooth as velvet...


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## VStar650CL (Nov 12, 2020)

Aftermarket cat and sensors, or OE?


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## Pos ses (7 mo ago)

VStar650CL said:


> Aftermarket cat and sensors, or OE?


Aftermarket, of course. Still several hundred $$$. OEM would run a couple grand. How much do they expect you to plunk down for a $3,500, 15 year old car that runs perfect? $1,000? (already been there), $2,000? $3,000? The purchase price of the car??? All of the junk I bought stated that it "met or exceeded" OEM standards. Seems that should be "close enough for government work", lest they are out and out lying, in which case, it would seem that the FBI should be notified about these blatantly fraudulent companies, peddling their fake wares. After all. It's the contaminated, molested environment that we're trying to protect, n'est-ce pas? They wouldn't DARE to mess with the crushing iron fist...


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## VStar650CL (Nov 12, 2020)

Lots of cheap aftermarket cats have low efficiency compared to OE and will cause dead-cat codes. You can usually get around that with a spacer on the rear O2. If the aftermarket sensor is crap, there's no cure for that. Most Nissan OE sensors are Denso so if you're looking for bargains, start there. Stay away from Bosch and from anything China-cheap.


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## VStar650CL (Nov 12, 2020)

PS - If you're gonna carry on over a 15 year old car like some 5 year old whose lollipop got swiped, that's all for me. Be serious.


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## Pos ses (7 mo ago)

OK. Not carrying on over car. Just thousands of dollars that I don't have. Time to get a real car that can be fixed. '59 Desoto. Apparently you cannot repair these piles for less than 5 grand. You just told me everything that needs to be said. UNFIXABLE. Thanks


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## Pos ses (7 mo ago)

VStar650CL said:


> PS - If you're gonna carry on over a 15 year old car like some 5 year old whose lollipop got swiped, that's all for me. Be serious.


Wadda jackoff...


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## Pos ses (7 mo ago)

Looks like I'll get nothing but grief here, with zero help, except maybe some jerk's nasty comment. Thanks for nothing.


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## VStar650CL (Nov 12, 2020)

I already told you, try spacers. But since you're obviously too angry for rational thought, you're welcome and bye-bye.


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