i just ran the self diagnostic for the check engine light and got 0303 which is a front left 02 sensor, iam short on cash and need to know what this thing does and if i need to replace it... also just before the cel came on i noticed a drop in acceleration, which may have been due to the faulty 02 sensors,
thanks for all advice
jesse

 

Replace it, otherwise you're car will run in open loop mode. In Open loop mode your car won't perform how it should. And one big side effect will be crappy gas milage.

Call courtesy Nissan and mention you are a maxima.org member, you get an additional discount.

www.courtesyparts.com

 

You arent quite understanding what open- and closed-loop modes are. Closed-loop mode is used at light throttle. This is when the car uses the oxygen sensor readings to determine if the car is running lean or rich, and makes adjustments in fuel delivery accordingly.

In open-loop mode, at more than 30% throttle or so, the car ignores what the oxygen sensors are saying and gives fuel according to a preprogrammed table.

The bad oxygen sensor will not give the computer correct info for proper operation in closed loop mode. This will adversely affect drivability and fuel mileage.

 

ok so is their anyway i can replace this part myself, i have acsess to a garage and all the tools.... or should i just buy the part and bring it to a nissan dealership.
thanks a lot you guys have been helpfull
jesse

 

Definitely do it yourself. You'll want to jack up the front of the
car and use jack stands for safety. The jack that came with the car
is not sufficient, you'll need to get a better floor jack from your local auto part store.
You'll need the following:
Floor jack
Eye protection
2 jack stands
22mm 02 sensor socket (any auto part store)
Permatex anti-sieze lubricant/sealer.
New 02 Sensor

Haynes manual for guidance if you have any confusion about what
you're looking for or where it is located. I think you'll be
able to find it on your own, especially when you have the new on
in hand and know what you're looking for.

Just follow the exhaust off the manifold of the rear cylinder
bank. You can get to it with a standard socket drive and your
02 sensor socket (it has a slit down the side of it to allow the
wire to pass through).

Unscrew, unplug, plug-in new, screw in new and snug it up.

Enjoy.

 

Sorry, for the front left 02 sensor it's the front cylinder bank
manifold you'll follow off of. This one is the easier of the two
to reach, IMHO.

 

I was told by the service manager at the nissan dealership that just because you have an CEL with an O2 sensor code, it doesn't mean that the sensor is bad or faulty. It just means that the sensor was reading out of its parameters. The problem could be something else, go ahead and pull the sensor and look at it. The wholes shouldn't be clogged, if you do a google search and look up bosch o2 sensors there is a lot of info about it.

 

Remember, knock sensor and O2 sesnor codes seem to go hand in hand. So, test your knock sensor while you're at it.

 

I was getting 03 04 and 07 07, I changed my spark plugs and you may have read the thread about the way they looked. I'm still waiting for the light to turn on. It was turning on after about 30 mile, and I'm around 50 miles with no light.

He was telling me that it is such a misconception that the light means a bad sensor. It usually means that the sensor was doing its job, but from what I've read it seems to do the job 90% of the time for the .org-ies(not orgys). I rememver seeing a website saying that a lot of times you can clean your heated O2 sensors with a brush rather than replacing them sometimes. I think it was a vw site.

 

well ok, all this information is great, but iam only getting a 0303 code witch is front left 02 sensor,,, is there a chance that my knock sensor is faulty too? wouldnt the ECU report that as well?

I think i may end up checking the knock sensor as well as the front left, and i may as well check the spark plugs.

any advice on how i should proceed is appreciated
thanks
jesse

 

It should show as a fault. I would focus on the O2 sensor.

 

What are you guys using to scan the ECU? I'm pretty sure no one here has the CONSULT scanner. I'm in the market for a scanner, but I want one that is 100% compatible and affordable. What do you guys think of those PALM pilot scanners?

 

We have decoder rings from our chocolate flavored ovoltine, what do you use?

Sorry,
I use the ECU diagnostic & reset function switch on the side of the ECU. Its never been wrong when I've had it ran with the computers at the dealership.

Honestly, unless you are a mechanic I wouldn't put the money our for such diagnostic equipment. I don't think that people get CEL all that often unless they like to tinker with out supervision or common sense. That didn't sound nice did it? I hope you can read between the lines to know I'm not being rude.

 

Before you go lay out cash for a new O2: Verify that the 03 03 comes up repeatedly after clearing out the error codes. Don't just do it if it comes up once. Also, I got the code repeatedly on my front 02. But when I disconnected and reconnected the connector several times, it hasn't shown up since!

 

by "clearing out the error codes", you mean reseting the ECU to see if the cel comes on again?, if it does come up again i will check the conections and see if i can fix it by cleaning it, otherwise i will buy a new sensor.
thanks for the info
jesse

 

i was looking into getting a bosch O2 sensor, from what i read they are identical to The factory ones and 50 dollars cheaper, i have also read that it is very bad to replace a part that is not identical. Should i use Bosch parts or not, I dont want to screw up my car in order to save 50 dollars
again thanks for the responses
jesse

 

Bosch is the factory part. Bosch produces like 95% of the heated O2 sensors used in automobiles.

 

My light came on yesterday and I got 0303 and 0304, O2 and knock sensor. Well, I just reset it and the light is off, and I am hoping it will stay that way...please dear god...

 

Do you feel slower lately? That is a big sign of a bad knock sensor. Also lower mpg will result in a bad sensor as well.

SuDZ

 

I was having knock sensor errors and rear heated o2 sensors for the last 2 weeks. I ordered a KS and an 02 sensor just to find out that I needed to replace my fuel filter and get the injectors cleaned. the ECU turned the light off and my car is much happier now.

 

does that mean everything is fine?

 

No, my car has always been very fast. No change at all. If anything it's gotten faster as it's gotten older. Gas mileage? 360 miles to a tank all city driving.

 

Wait so R U saying that it was only a fuel filter?

 

Well its hard to say, I think it was more of the gummed up injectors. The thing that made me look at getting the injectors done was when I pulled my spark plugs they were WHITE, which means my car has been running very lean. Also a symptom of a knock sensor. so I took a chance and it worked.

 

Ok, let me try to understand here, you're saying that your light came on and gave you 0304 (knock sensor) and you simply changed the fuel filter and the code went away?

 

I was getting 0304 I went and got my fuel filter AND my fuel ijectors cleaned and it went away.

 

Just want to add my little 2 cents - I have gotten the O2 and Knock MIL 3 times and just reset them. I still get the same Gas milage - a minimum of 400 miles per full tank. (but my car does feel a little sluggish).

 

Hmm....I've got 76k and I'm still on the original fuel filter, I've been meaning to change it. Maybe I'll get lucky like you. BTW, what did u do to get your fuel injectors cleaned? Did u just buy something? Did u reset the ECU after u got all that done?

 

I had it done at a garage, and I was going to reset it myself when I got home but on my way home it went off by itself.