Tech notes Before replacing the Mass Air Flow (MAF) sensor, try replacing the air filter and cleaning the MAF sensor with low compress air or MAF sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the MAF sensor. There is a factory service bulletin for the following Nissan Models: 2011-2012 Nissan Altima Sedan If the P0101 code is set and there are no drivability problems, the factory service bulletin suggests reprogramming the Engine Control Module (ECM) to repair the problem. Bulletin No. NTB12-051d
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