# Engine code P0101 maf



## Damayor42 (Apr 24, 2016)

After replacing mass air flow sensor, light came back. Went back and read codes but this time P0101 is back plus reprogram ECM. can there be something else besides that?


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## rogoman (Dec 16, 2004)

Please state the year, model, engine, transmission of your vehicle. Detail your original problem along with any tests you performed.

I'll jump ahead and indicate possible causes for a P0101 fault code before you reply to this post.

Possible causes:
● Harness or connectors (The sensor circuit is open or shorted). A high voltage from the sensor is sent to the ECU under light load driving conditions.
● Mass air flow sensor is defective.


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## Damayor42 (Apr 24, 2016)

2013 Altima 2.5 SV. Original problem said P0101. I replaced maf sensor. Light went away for about 2 weeks. Light back on now this. Maf and reprogram ECM


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## lmd2018 (Feb 11, 2019)

Did you get your issue fixed? Having the same issue.

Thanks


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## Darren Bracey (Jul 4, 2019)

My 2016 Nissan Altima did the same exact same with the p101 mass air flow sensor there's a service bulletin out on it at the dealership not a recall but a service bulletins and they fix mine for free they had to reprogram the ECM


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## rogoman (Dec 16, 2004)

Here's some other possible causes that you can check out:
• Intake air leaks. The best way to check the intake system for a vacuum leak is to attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
• Defective EVAP control system pressure sensor. For diagnostic procedure testing, reference the FSM.
• Defective intake air temperature sensor. For diagnostic procedure testing, reference the FSM.

Diagnostic procedures are documented in the FSM for your vehicle. You can download a copy of the FSM from this web site: https://ownersmanuals2.com/. Section EC.PDF is the one you need to read.


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## Giorvy (Apr 17, 2021)

rogoman said:


> Please state the year, model, engine, transmission of your vehicle. Detail your original problem along with any tests you performed.
> 
> I'll jump ahead and indicate possible causes for a P0101 fault code before you reply to this post.
> 
> ...


I had the same issue with a 2012 going into limp mode and throwing the P0101 code and it ended up being a dirty throttle body !


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## VStar650CL (Nov 12, 2020)

Giorvy said:


> I had the same issue with a 2012 going into limp mode and throwing the P0101 code and it ended up being a dirty throttle body !


There are various bulletins for P0101 on all the Alties from '11 up, and most of them call for an ECM reprogram. One thing is certain, even though P0101 is a MAF code, the MAF itself is almost never responsible unless it's dirty or obstructed. Auto Zone must make a fortune selling unneeded replacement MAF's.


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## Kbodily (Jun 27, 2021)

Giorvy said:


> I had the same issue with a 2012 going into limp mode and throwing the P0101 code and it ended up being a dirty throttle body !


Did it only go into limp mode when driving for about an hour or longer? Mine is doing the same thing but only goes into limp mode after driving at least 20 or 30 miles


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## Sdog (Nov 17, 2021)

I have a 2012 maxima and must share this. At 50k got a P0101. I Replaced MAF & code returned. Since it seemed to be running ok I put it on the back burner. Performance slowly degraded and at 58k I dove deeper into this. I borrowed a good scan tool from a friend and started diagnosing. After going into the Nissan Enhance Program it showed a code for the CVT transmission manual switch. I decided to drop CVT pan and replace the NS-2 fluid. Also, replaced CVT fluid cooler filter. I removed 4 quarts of fluid but it took 5 quarts to refill(center of hash marks while running and hot). Guess what happen next? The P0101 MAF sensor code dissappeared along with the CVT manual switch code. I cannot believe how good this car is running and gas milage improved. Diagnosis with a scanner that can read Nissan codes is a must! My friend that lent me the scanner told me the transmission and engine communicate with each other. Sometimes the tranny has an issue and tells the engine to do strange things with air fuel causing the P0101. So, my problem was the tranny. Low CVT fluid and diry filters caused this issue.


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## VStar650CL (Nov 12, 2020)

Sdog said:


> I have a 2012 maxima and must share this. At 50k got a P0101. I Replaced MAF & code returned. Since it seemed to be running ok I put it on the back burner. Performance slowly degraded and at 58k I dove deeper into this. I borrowed a good scan tool from a friend and started diagnosing. After going into the Nissan Enhance Program it showed a code for the CVT transmission manual switch. I decided to drop CVT pan and replace the NS-2 fluid. Also, replaced CVT fluid cooler filter. I removed 4 quarts of fluid but it took 5 quarts to refill(center of hash marks while running and hot). Guess what happen next? The P0101 MAF sensor code dissappeared along with the CVT manual switch code. I cannot believe how good this car is running and gas milage improved. Diagnosis with a scanner that can read Nissan codes is a must! My friend that lent me the scanner told me the transmission and engine communicate with each other. Sometimes the tranny has an issue and tells the engine to do strange things with air fuel causing the P0101. So, my problem was the tranny. Low CVT fluid and diry filters caused this issue.


Good dig! AutoZone et. al. must make a fortune selling unneeded MAF's because of that code. Even though P0101 is a "MAF code", the one thing that almost _never_ causes it is a bad MAF. It's a "performance" code as opposed to "flatline" and it usually represents the ECM blaming the MAF for some other problem in the induction system. That might be a butterfly wing stuck in the MAF, but not a _bad_ MAF. There are bulletins for P0101 on a huge variety of Nissan/Infiniti models since around '04, and all of them are ECM repros to correct restrictive A/F Sensor maps in the ECM's program. But as you found out, even problems in an another system can sometimes cause a confused ECM to throw P0101.


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