One is mass air flow sensor, the other is the nox sensor. Is this correct?

What happened? Is my mass air flow sensor dirty, and causing the Nox sensor to be reading some incorrect data?

I need input. A day before these codes came, my maxima did a couple jolts and momentarily lost power, and then cruised on smoothly. No code came up when that happened but the next day, just driving normal with smooth engine operation, the CEL came up and my OBD 2 checker came up with P100 and P325. Otherwise the car runs very smoothly.

Help!

 

Clean MAF with MAF cleaner.

 

Did you even bother to search ?

 

Is the P325 caused by the P100 MAF sensor problem/dirty MAF sensor?

Changing a knock sensor/P325 is a bear! It involved removing upper and lower intake manifold.......and lots of other thingys. Very, very expensive for a person on a limited budget here.

Was hoping your reply meant that the Knock sensor reacted to the MAP going "hay wire" with air fuel mixture controls.

 

You shd do a SEARCH. THere is a lot of useful info on the org, all you gotta do is look.

THat bein sd, the org has developed a proven method of replacing the KS that does NOT include removing the UIM as u read in the FSM or HAYNES. the thread for removing the KS is located in the HOW-TO section. Read the entire thread cuz different ppl used different strategies.

No the KS and MAF are two unrelated problems. Both SHD be fixed.

 

Seems like my search function wasn't working, or I was doing something wrong.

However, I just finished replacing my knock sensor using the less expensive and time consuming method, that a Maxima.org member had shared via photos and instructions.

Also, bought some MAF sensor cleaner from the auto supply and sprayed/cleaned the sensor, dried it out, and re-installed it.

Took the car on a 70 MPH. run down the freeway for a few miles and back home, and didn't experience any engine jolting, surging, hesitation, etc..

Seems like the idle is a tad smoother, but can't say for sure.

I'll be using the car around town(San Jose, Ca.) for various trips/errands and will see if the problem and CEL's are done for now.

I got the new knock sensor through Ebay from an auto supply in Wisconsin. It took about 3 days to get to San Jose, Ca.. Cost: $22.00 and no shipping charge.

I called all over our area to many auto supplies and the cheapest new knock sensor was $80.00, and some places were charging $140.00+!!!
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Upon inspecting my old knock sensor, I noticed that the plastic casing had a fairly large crack in it. I was told that this was not a good sign.

As for the wiring going to the sensor, it was solid, and not cracked or loose in the connector.
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One thing about getting my hands down into this tiny little opening under the intake manifolds to access the knock sensor was that there was a little switch with three vacuum hoses right in front. This made access nearly impossible even though my hands aren't extraordinarly large. This little switch was bolted to a metal bent metal mounting plate with a 10 mm nut. The 10 mm nut was under the switch/metal mounting plate right in front of the opening that accessed the knock sensor. Fortunately I was able to get a small 10mm socket and box wrench underneath the switch mounting plate and remove the switch. This made hand-access under the intake much easier to get at the knock sensor.

All told, I saved a lot of labor hours as the other way of removing the knock sensor involved removing the upper and lower intake manifolds as per Haynes, and most likely Nissan's work manuals. This would also involve unplugging many wires, having to i.d. them, intake manifold gaskets purchased, re-torquing the manifolds...........Ugh!!!

Well, as the Maxima.org member who supplied the info to get the job done in much less time and money, I have very sore and raw wrists and knuckles, but I've saved hundreds of $$ in parts and labor.

All said, if your hands are too big to fit in that hole under the intake manifolds.........your up the creek without a paddle.

 

Chalk up another win for the org!

 

8ball--

I had the exact same problem a couple of weeks ago. A jolt and loss of power on the freeway, then stalling. No CEL, but I scanned codes anyway and got a P0100. I cleaned the MAF off real well and cleared the code, and it was fine--for a week. Then it started stalling again, multiple times. I had the same code, so I ordered a used MAF sensor. It should be here today. We'll see if that fixes it.

It's highly unlikely your problem was caused by the KS. So be prepared for it to return...

 

I did have a P325/knock sensor besides my P100 so I'm hoping that I have taken care of things.

If I have to replace the MAF sensor, I've seen brand new ones on Ebay for roughly $80.00-$90.00 with I believe free shipping.

I maybe ordering a MAF sensor too, if this doesn't work out.

 

Even though I haven't experienced a return of the engine "jolting", I ordered a new MAF sensor from Ebay on Tuesday(2-16-10) too.

Think I got a good deal at $84.99 and free shipping.

Also have been wondering if a dirty fuel filter could cause the "jolting" symptoms? Would one get a P100 and p325 code because the engine momentarily starved for fuel because of the fuel filter? Those codes would be thrown if the engine goes extreme-lean for a moment?

 

yo man...change filters and use injector cleaner. Thats my motto .

Fuel Filter only 10 bucks.

 

Just picked up a WIX fuel filter. I looked at the Frams, but I hesitated. I have a Cummins diesel powered Dodge truck, and there have been some horror stories with Fram oil filters messing-up the Cummins engines. The paper element would break down and get sucked into the diesel's oil gallerys causing a very messy and expensive fix.

WIX and NAPA filters seem to be preferred.

Also noticed that the WIX fuel filter is all metal, while the Fram had a plastic bottom for the inlet end?
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Get ready for this! Stopped by my Nissa dealer, and just asked on the price of their MAF sensor.........Over $600.00+!!!!!!!!!!!!.

I paid $84.99 from Ebay. Wonder if the quality is any different?
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Looks like the fuel filter fits into a clip, but of course the outlet and inlet hose must be loosened-removed. Why oh why did they put that filter in such a tight place against the firewall?
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THey do that so they can make yur hands bleed...bleed real bad lol.

JK man...its not that bad. I jus did my fuel filter.

Autozone sells MAFs now. I saw it online. THey still over 200 bucks and remanufactured but than the dealer. Its the same concept as the starter. MAF comes with 1 yr warranty

 

and when the new MAF can u perform a much need public service and inspect the old MAF and compare to the new one to see what broke.

 

Problem is; when I cleaned the old MAF it looked just fine.
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Also, I just finished putting in a new fuel filter(Wix brand) today.

Now I have more raw cuts and scrapes added to my knock sensor installation wounds.

By the way, those Nissan factory clamps on the upper and lower fuel line hoses were a bear to remove. They had those stink'n little Phillips screws.

I replaced them with the band type clamps that have !/4" hex head screws.

The bottom hose clamp was the most miserable one to remove.

Nissan had a special for $100.00 parts and labor to replace the filter. I'll tell yah, part way through doing it myself, I was really wondering if I was going to get it done.

Anyway, the engine started up quickly, and it seemed like the throttle responded a little quicker than before.

I'm still wondering if I should just wait on installing the new MAF and just keep it in the garage for now when it arrives. If the engine starts jolting again, I'll install it. Otherwise I'll have when the MAF does go bad for sure.

The Maxima seems to be idling smoother and the accelleration seems better since cleaning the MAF, replacing the Knock sensor, and now replacing the fuel filter.