MAS Problems?

Anybody have any issues with the Mass Airflow Sensor?
2002 SE/SC Auto 4WD. Had to have mine replaced with less than 500 under the belt. That is what Nissan said at least, pulled out to pass someone on the highway and about 3 seconds of passing gear, it was like the ignition was shut off and the CES light was on. Tach was reading 2100 RPM, pressing accel did nothing. Pulled off the highway and shut it off. Restarted and took off as if nothing happened. Dealer checked the components pointed to by the computer.....all checked good. 4 days later, same sort of thing but did not hit passing gear. Took it back Friday before Christmas, just got it back Thursday night. No issues so far. Just wondering.

Haven't heard issues like that, might just be an isolated case. Since you still have the warranty just ride the Dealer's ass till they fix it.

Thanks for the reply. They were pretty freaked about it on my second visit.
The dealer has gone out of their way to get it resolved.....Nissan even paid for a mid size rental for a week instead of the standard econobox.
And I picked a 4WD instead of a car. Made me wish I had my X back. You just don't know what ya got until you have to step down.
Anyway, got a free vac, wash and wax out of the deal too.

I had the same problem tonight.I was on the highway doing about 70MPH,i went to pass a truck and she started die......slowly.
The CES light came on and i shut the truck off and restarted her.........runs good,but the CES light is still on.
My X only has 1700 miles on it and this SUCKS!
I guess it's time to bring her in.

[ 12-30-2001: Message edited by: dvldog458 ]

My dealer saw no bulletins about this. They called Nissan who airfreighted a MAS overnight.

You could make mention of my problem to your dealer and maybe they could cross-ref with Nissan and hopefully expedite your repair.

Have you had any problems with X after the MAS was changed?
I hope that does the trick.........This discrepancy could get dangerous.

Lex,
How hard do you drive your X?
I'm thinking maybe i drive it alittle harder than the average person,and maybe this could cause the problem.

Let's just say the people from work don't ride with me to lunch....they think I'm crazy.

As far as the situation, I have been doing the same things that caused it in the first place and have had no CES light.

As for the danger aspect.......I agree 100%. If you tried that little maneuver on a 2 lane blacktop......someone would get hurt or worse.
In my situations, both happened on a 5 lane highway and sparse traffic. I was able to get over fast and out of the way.

[ 12-31-2001: Message edited by: lexicon5 ]

Lex,Thanks for the help.
I'm gonna call th dealer today and setup an appointment to bring the X in.
I'll keep u posted on how i make out.

Lex,
I also posted our problem on another message board to see if anybody else had the same problem. http://www2.4x4parts.com/cgi-local/ultimatebb.cgi?ubb=forum&f=2

MAS is NOT....I REPEAT, NOT the answer..........
Same circumstances......getting on highway tonight.........dimwit in front of me doing about 30 MPH getting on 65 MPH highway, I paused and let her get over then I hit the afterburners since the acceleration lane does not end, it just continues as another lane of the highway. About 2 seconds later.........nothing.........I never got to 65 MPH.
This sucks........I have to give up the X AGAIN!! The dealer will have had my X longer than me.
At least I'm narrowing down list of possible components.
E-Mail me at
lexicon5 at netscape dot net
and I'll give you my Dealers name......maybe they can share info and get this freakin' thing fixed for both of us.

I'll e-mail......maybe we could figure this thing out.

Back in for the third time on the same problem. It does not seem to be the MAS. It is brand brand new and the same thing occurred.

Nissan wants more tests run.........dealer has it for a couple of more days.......
Hopefully, they will find the culprit.
They were able to reproduce the problem.......tech said it was pointing to a emissions problem. A sensor gone south for the winter.......?!?

I just wanted to let you guy's know, that it is in fact the SC itself, i'm not sure exactly what,but they(nissan) plans on getting some part? in on the 15th of this month, and It should then be fixed. be patient, and call your dealers, and inquire. It's throwing the system into a fail safe.
Peace>>>>>>>>>>>

Update.....dealer will have Xterra for another week.......
Tech said that Nissan knows about the problem.
If they had a fix.......would it not have been implemented yet?
I've called my salesman to find out what they, the dealer, is going to do about a vehicle that is brand new out of the box that I can't drive.

I'm not hacked at the dealer.....this is the doings of Nissan. Had the dealer known what Nissan knew already, I might be driving my XTERRA right this very second instead of typing this drivel.

Lex, knowing about a problem and finding a reliable solution to it are two different things. It could just be a vacuum leak, or it could be an leak internal to the supercharger. Whatever the problem turns out to be, Nissan might be having a problem getting replacement parts.

The tech called me today and told me my MAF sensor is on back order and he'll call me when it comes in.
He also said he has another X there with the same problem.

No, I realize the Problem/Solution dilemma. It's just annoying as all get out to buy a new vehicle, drive it for a while, take it back....drive a little while longer....take it back again.....leave it, pick up rental car, change weekend plans, change work schedule, drop off rental. Get the X back, drive a little while and do it all over again.
Just not my idea of having fun.

The fix for the 2002 Xterra S/C is to reprogram the ECU. Replacing the Air Flow Meter will NOT fix the problem. As a matter of fact a number of them are currently on Back-Order because the dealers are Not checking the current (1-1-02) TSB Cd. Just a matter of re-programing the ECU and your done.

Note: this is ONLY applicable to the 2002 S/C Xterra's and Frontier's.

Nut

i had a 2002 xterra that was doing the same thing. it would quickly decelerate and not go over 20-30 mph. the dealership could never determine the problem and ended up giving me a replacement vehicle. after reading this, i'm not sure how safe i feel in the replacement car.

Is this problem with all supercharged models both the manual and auto? Also, should I be taking mine in to get reprogramed even if I am not experiencing this problem. Mine pulls 70 up to Eisenhower Tunnel if the traffic will allow for it (10,00ft).

I picked up my X today.....they changed the MAS.
This better frigin work!

CheetaraX: The deciding factor is the current ECU program/part # (software version if you want). If your not having a problem I wouldn't make a big deal about it. Possibly next time you go to the dealer for an oil change or whatever mention it and have your ECU # compared to the listing in the TSB.


dvldog458: As long as they checked and/or changed the ECU software your fine, if not

Nut

If you are not having the problem, maybe not but the power lag is sudden and severe.......I mean like somebody turns the engine off.........so you'd know if you were having the issue.
It is still running though but in a protect mode......nothing over 2000 RPM.

I'm on the phone with the dealer............he is checking the TSB dated 1-1-02. He also talked to Nissan, they said they were not going to release the fix until 1-15-02. He said that it was unbelievable that I am able to find out about a fix before Nissan releases it........so he is checking again with Nissan.

Bullshit, nothing but BULLSHIT. As stated before the dealers are ordering/replacing the Air Flow Meters because they are not che cking for the TSB. It is currently available and downloadable from the 1-1-02 Cd into thier Consult Diagnostic Equipt. and then uploadable into your specific veh ECU. The only criteria is the Current ECU software #. Nissan is well aware of the problem and advising the dealers to NOT replace the Air flow Meter but to reprogram the ECU for that specific fault code and veh, ie. Air Flow Meter fault on a S/C 2002 Xterra or Frontier.

Sounds like they either don't know how to due it (it is kind of a PITA) or they haven't loaded the most current Cd.

Good Ruck,
Nut


:rolleyes:

Good news, bad news........
Nut........you're right. It requires a reprogram of the ECU...........now, after I was on the phone with the tech, he called Nissan and found out the scoop............Nissan told him yesterday that yes in fact a reprogram is what will fix it........but........the total procedure is not going to released until Jan 15th. I asked if I could get my X back if I promised not to drive like Steve McQueen until then, Nissan will not release my vehicle due to safety concerns.

So, it looks like dvldog, you're gonna need to take another trip back to your dealer........still unclear as to if this is a Auto trans only issue.........

Sounds good Lex.
Good job stayin on their ass.

FWIW: The update is currently available. Sounds like the dealer hasn't updated his TSB info or has another internal problem to put you into a holding pattern until next week. I've seen the Cd and I've seen the applicable program. Maybe we just get the info sooner on the Left Coast.

No clue.....it could be that since California has such strict emissions laws/standards that it is a different fix for that states vehicles.

[ 01-13-2002: Message edited by: lexicon5 ]

Got my X back tonight.......12 days without.....man was I ready.
Nut was correct...a re-program of the ECU appears to have done the trick.
I've stomped and romped trying to get it to screw up again..........
No problems so far.

Hey Fellas,

Excellent work on the research and information on this issue.
My X is doing the same thing, I thought it was the gas (maybe Gate's 93 is really only 89, etc), but this sheds a tremendous light on the whole subject.
I just called my dealer and the technician said that he is full aware of the situation and that it is the ECU, additionally that they were told not to order anymore AIR units and to cancel any on back order.
So I am scheduled for Thursday morning to get reprogrammed.

Thanks again!
Silver Ice 2002 S/C SE 4x4

Question for all you experts........
Is it possible for my gas mileage to have gone way up because of the reprogram?

I hit it hard tonight, on and off of the highway several times, passing gear......everything that had caused it before and nothing........I'm cured.......

Road report in recent magazine suggest SC is NOT online full time (surprise to me) but only at "Full Throttle" which means something has to control it. No info about this in online Owner's Manual. Perhaps this is source of random loss of power. I welcome others input.

This is erroneous info.........
A roots type blower, which this is, is turning as long as the engine is running.
A. It is belt driven
B. There is a shaft that connects to the rotors
C. There would be no point in a part time blower.
D.. There is no clutch that "turns on" at a certain RPM.
Anybody who watched Mad Max and saw him hit a switch to "turn on " the blower was watching Hollywood
directorial license.

Check this site for pictures of the blower, not unlike the one on the SE/SC Xterras. http://www.theoldone.com/articles/damaged-blower/

The rotors DO NOT turn inwards, they spin away from each other and drag the air around the walls of the housing. Since the tolerances are so very tight, there is
not enough room for air to squeeze around the rotors and into the engine if it were not turning.

As far as the performance issue.....it is the ECU that needs reprogramming. I am not positive but I think that there were some ECU installed into the SC models that were for the normally aspirated engines. The programming did not take into account the added pressures and such.

Another link with a good description of what a blower does: http://www.tpub.com/engine3/en32-5.htm

[ 01-19-2002: Message edited by: lexicon5 ]

What they might mean is that the SC is not very effective at lower RPM.

...which is a good thing if you want to get anywhere near an average of 15-17 MPG

I had the MAS problem at 2,000 Miles. Got a new sensor and everything has been peachy for the last 4,000 miles. We'll see how long it lasts.

Lex: Thanks for S/C Primer. Sounds logical and possible that journalist had "erroneious info", saw post in another thread about modified pulley discussing "bypass valve" in back of housing. Wonder if this is what they were talking about (no forced induction below 3000). I agree this would be strange arrangement and don't understand how low end rpm would suffer that much from S/C. Also wonder if this accurately describes system, and how does it handle the "shock" of sudden induction boost at whatever RPM the valve closes. Hope you can understand my confusion. It relates to intake and exhaust mods that seem popular on normally aspirated models, which may not be a good idea in an attempt to achieve higher power. Can't seem to get much tech support from dealer. Appreciate your patience and welcome your system knowledge.

same deal, dealer has upgraded computer codes now!

Help!!

My X did the other day as I was going from 4th gear to 5th on the freeway. I pulled over, restarted the X and away I went along with the "service engine soon" light on. Cerritos Nissan found a P0103 MAF SEN/Circuit code and would not further diagnose the problem because of my Stillen cold-air intake. the problem I had appears to be related to this post. Gave the dealer and the Nissan consumer advocate the 01-01-02 TSB CD info. I'm currently working with Nissan Consumer Advocate (NCA) as the dealer wont return my calls. She (NCA) stated the dealer said there are no known SC and MAS issues let alone an ECU code upgrade. Can any one out their give me the name and telephone number from the dealers mentioned in this thread who are aware of this issue. Can any of you remember the error code you received when this happened? They're really beginning to piss me off!

Correction - My X died the other day........

The fix was released last Jan 2002 or Feb 2002. It has to do with the wrong module being installed in the SC models. A simple reprogram makes it right as the SC parameters are included......
Yours could be a different issue. In the cases that I know of.....mine included......the engine did not die it just went into protect mode limiting RPM to 2k.

You would have had the problem right out of the gate......it is not something that would occur weeks or months after purchase.....
The first time I hit passing gear is when it happened to me.....

Now that you mentioned it, I can't say it died. Don't recall the dash lights coming on. Just pulled over and shut it down then restarted.

I didn't just purchase the vehicle true but I just moved from Colorado where the air density is significantly less than sea level. Was only getting 5 lbs boost in CO. I'm thinking this could be a factor why it's occurring now if it is the same issue. Do you still have your receipt from Nissan, as it should list the error code you had when yours failed. Would like to make sure either way, as I'm getting no help from the dealer.

I can't remember if I had a receipt.......warranty work.....rental cars paperwork......money never changed hands....too long ago.

I know the tech had to bug Nissan about it and was a little PO'd that the info and fix for it made it to the Internet before he even received the bulletin.....
My third trip in is when I told them of the info gathered here. Nissan made sure that they did not release the car to me until the fix was released by them to the dealers and applied to my vehicle. The dealers all have access to the internet....point them here if they do not believe you.
It is an EXTREME safety hazard.....in my case the first time it happened, I was on a 5 lane and 4 lanes away from safety when I lost all power in RUSH hour......NOT the time for that to happen!!

Mt dealer is Suntrup Nissan Volkswagen at 6000 S. Lindbergh St. Louis, MO.

Gster,
The code set for that specific problem is for the Air Flow Meter which is why people were replaceing them initially. The dealer who pulled the fault code should be able to supply you the ECU # (it prints at the top of the print-out which lists the fault codes automagically) and then compare that to the application in the TSB. It shouldn't be rocket science but sounds like the dealer is being way more then difficult.