MAF sensor and need for PCM reprogramming

A forum for the Nissan Quest... minivan lovers unite!
dbailey
Posts: 21
Joined: Thu Oct 06, 2016 7:35 am
Car: 2012 Nissan Quest SL

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I have a 2012 Quest SL, 110k miles, and the malfunction indicator lamp (MIL) has been on for about 1000 miles with no change in performance. Autozone told me the code corresponds to the mass air flow sensor (I do not have the code: I intend to verify). So I pulled the MAF sensor out and cleaned it with CRC MAF cleaner. The MIL did not disappear immediately, but it did after maybe 2-3 days. A week later, it is back again and my local mechanic said I need to take it to a dealer for the PCM to be "flashed" (reprogrammed) and the dealer says that it would be no good to do that without installing a factory MAF sensor first -- all in that's around $500 to the dealer ($270 sensor + $70 labor + $130 reprogram ...). Has anyone experienced this issue? Can anyone confirm that if I just install a new (aftermarket, $30-60) MAF that I really have to take it to the dealer for PCM reprogramming to clear the code? It literally takes 10 minutes to change.


far raf
Posts: 213
Joined: Tue Feb 21, 2017 2:53 pm
Car: 2005 Nissan Quest SE (standard? simple? edition - i.e. nothing special)

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Re-flash or re-program by the dealer is a scam. Most they can do is idle re-learn.
If you cleaned, and still got the code, you need a new MAF, period.

amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

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Not so. They can reflash the ECM software response to every sensor on the cars, the MAF does not change, rather the ECMs' response to the signals from it. And, idle learn takes a far distant second place to overall airflow learning.

Having said that I'd verify the code is indeed for MAF, NEVER trust the techs reading your codes for you, ALWAYS look over their shoulders or better yet demand to see the code itself. And for heaven's sake don't be silly and not write it down IMMEDIATELY, so many do that then bumble around saying they thought it was this or that code and then the cars get screwed up even worse.

far raf
Posts: 213
Joined: Tue Feb 21, 2017 2:53 pm
Car: 2005 Nissan Quest SE (standard? simple? edition - i.e. nothing special)

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They can, but that will not fix the code. And if installing a new MAF fixes the code and the van drives great, there is no point in re-flashing.

amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

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X2 on that. So many software fixes now cause only more troubles. Just like with a home computer, if it appears to work fine then don't do something silly like changing EVERYTHING up for just one part which may just be broken.

I myself turn down all software updates until the need for them is 100% proven out to be needed and the dealer guy telling me that is NOT proof of that. One reason being that software updates are one of the easiest things to botch up, they must occur 100% perfectly or the car can be bricked in seconds and most techs do not give that fact enough import now. As well, once you upgrade UP, then going back down to where it was before is often not an option.

The 'Rule of McDonald's' most certainly applies there.

dbailey
Posts: 21
Joined: Thu Oct 06, 2016 7:35 am
Car: 2012 Nissan Quest SL

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Ok - thanks very much for the help so far! The code is P0101.

I replaced the MAF sensor with an aftermarket (the Nissan part costs $283). And I reset the codes with the peddle procedure.

I drove about 35 miles and the code eventually came back. No rough idle or other symptoms; no change in fuel economy.

Are there any other steps or do I surrender and go to the dealer?

04pathse
Posts: 776
Joined: Sun May 02, 2010 2:55 pm
Car: 2004 Nissan Pathfinder SE
2008.5 Mazda Mazdaspeed 3

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dbailey wrote:
Sun Oct 07, 2018 7:29 am
Ok - thanks very much for the help so far! The code is P0101.

I replaced the MAF sensor with an aftermarket (the Nissan part costs $283). And I reset the codes with the peddle procedure.

I drove about 35 miles and the code eventually came back. No rough idle or other symptoms; no change in fuel economy.

Are there any other steps or do I surrender and go to the dealer?
It is also possible that you have an intake air leak somewhere did you check for any cracked, damaged or loose hoses?

If no signs of air leaks you may need to take in to get reprogrammed after all, I did a quick online search and found several instances where reprogramming the ECU/ECM is the recommended fix.

dbailey
Posts: 21
Joined: Thu Oct 06, 2016 7:35 am
Car: 2012 Nissan Quest SL

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Thanks for that - i've checked the hoses and all looks OK. I took it to a highly recommended Japanese automotive mechanic nearby and he kept it for about a day only to say that he can't find anything wrong with it. He things the computer needs to be reprogrammed, so I'm taking it to the closest Nissan dealer. I will update this thread when I get an answer.

amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

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Anybody ever change the air filter? Restriction there can throw off MAF calculations to be close to one end of the operating spectrum.

dbailey
Posts: 21
Joined: Thu Oct 06, 2016 7:35 am
Car: 2012 Nissan Quest SL

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Hi all - I did first check the air filter and how it was sitting and that the box was closed snug (the box can tricky to get aligned and closed correctly).

SO - I took it to the dealer and they said that in addition to the P0101 code it was also running too lean (I think this was P0174). They found that the rubber boot between the throttle body and the "snorkle" (solid top of the air filter box that also includes the MAF sensor) was dried out and cracked in two places. I never took this piece off for inspection: I assume they did in order to inspect the throttle body.

They replaced that part and performed a fuel induction cleaning and an idle relearn.

After a coupon, it was $388. They left the aftermarket MAF sensor in, and sent me home with the original MAF sensor I took out (which is probably still functional).

Code is gone; van is running great.

far raf
Posts: 213
Joined: Tue Feb 21, 2017 2:53 pm
Car: 2005 Nissan Quest SE (standard? simple? edition - i.e. nothing special)

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I had this same problem with the Honda Pilot, where the rubber boot hardened sheared around the clamp at the engine side, but my Quest still has a relatively soft duct. Thanks for posting, I'll inspect mine more carefully.


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