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2012 Sonic running lean

donnah57donnah57 Chico CAPosts: 2
edited August 2018 in Chevrolet
P0171 System too lean
P0101 MAF Sensor Signal Range Performance
Anyone else have this?
How did you fix it without mortgaging your home to the dealer?
My brother is an excellent mechanic, but less familiar with newer cars.
Donna

Best Answer

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,249
    Accepted Answer
    The MAF (mass air flow) sensor is a sensor mounted in your car's engine air intake plenum further down the tube from the air filter. The MAF measures both the volume and density of air being sucked into the engine.

    The PCM (car's main computer) uses the reading from the MAF, along with readings from other sensors, to calculate the proper air/fuel mixture.

    What's wrong? Could be a number of things:

    Dirty or contaminated MAF.

    Bad MAF

    Vacuum leaks

    Electrical wiring problem, like corrosion, broken wire, chaffed wiring, loose connection.

    Also possible is a clogged catalytic converter.

    What can you do on your own?

    Check the MAF wiring.

    Visually check the MAF sensor wires (thin metal wires in the intake, not electrical wires) for dirt or contamination on them.

    You can GENTLY clean the MAF with a special MAF cleaner spray you can buy at the parts store. Be very careful.

    Loss of vacuum to the MAF could set the code.

    Check for air intake leaks (you can google how to do this).

    If none of this works then you'll need a professional scan tool to measure the MAF's real-time sensor values.

    You'll also need a technician for the clogged catalytic test.

    So, tell Bro to check for intake leaks, check all the wiring for obvious problems and clean the MAF sensor.



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