so last night i got a CEL, and i just pulled the codes. Its my first time doing it but i wrote the pulses down about ten times so im positive i got it right. I got two codes:

03 04 - Knock sensor
04 09 - "Undefined"

Anyone have any idea what the second one is? Or is it just some sort of "phantom code"?

 

Also im having problems getting it to clear. It just stays there and laughs at me, is this normal?

 

It won't clear because you haven't fixed the problem.

 

ohhh ok, i misunderstood what i was reading then.

 

where do you guys reccomend buying the KS from? I'm weary of ebay for things like this, but AA wants 188.99 and ill pull one from a low milage junkyard max before i spend that.

 

From what I hear the $60 ebay ones seem to work perfectly fine. I'd just go with one of those.

 

Thanks Hopefully someone knows what this 04 09 code is, i cant seem to find an answer searching around unless im missing it.

 

the 0409 code has to do with the evap system. i cant remember just what it it. but ive had it several times in the past. first go through and make sure all of you vac lines are connected under the hood. ill post later if i remember what i did to fix it.

 

Wait it out because I got a cel on my car twice and it was the KS and a 02 sensor. I waited it out for a few days and it went away on it's own and I was just about to buy both from Autozone when I got the cel and lose some money.

 

the car has 150k it is probably overdue for a KS anyway. As for the vac lines that would help explain the cold start issue it has every so often. 1-2 days a week when i start it cold (even if its hot outside) it will start and either struggle for a sec or stall out and i have to start it again and tap the gas pedal. One tap and its fine for the rest of the day.

 

There is an ebay vendor who sells brand new OEM Knock Sensors, I can personally attest to their quality. Where ever you get it though, don't waste your time going to a junkyard and getting a used knock sensor, that's like trading mud for dirt. Get a new sensor or dont even bother.

As for your intermittent stalling issue, buy a new PCV valve from Nissan ($15) and follow one of the many write-ups on the Org for replacement. You should also clean your IACV and EGR guide tube. Also change out your spark plugs (only on a cold engine) and analyze the old ones for indications into other underlying conditions such as running too hot, lean/rich, or the presence of carbon build-up. My guess is you would see a dramatic improvement from a concentrated injector cleaning at a Nissan dealership, they charge about $150 in NYC.

P.S. - 0409 I believe is the Evap Purge Volume Control Valve which can become encrusted with residue from gas vapors, it is however a semi vacuum-actuated system so try the fixes I mentioned first to bring back healthy overall engine vacuum.

 

Thanks guys, this stuff has to wait a few weeks but im going to do it all when i do the oil change