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2001 Ford Explorer Question: I was told that System too lean Bank 1 and System too lean Bank 2.

 

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Lar_Arr2, 4.0L V6, Carson City, NV, July 31, 2013, 23:52
 Rookie

Codes Bank 1 po 171 Bank 2 Po 174
The "check engine" light came on so we had a 100,00 maintenance done on it. It ran for only 20 miles when the "check engine" light came on again. The shop gave us the codes but said that it was beyond their knowledge to be able to fix.

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  • Answer #1

    lightsaber August 01, 2013, 03:26
     Technician

    From the Haynes manual:
    If both cylinder banks on a V engine are lean, the fuel pressure might be too low, there may be a vacuum leak, the ECT sensor could be skewed toward a higher temperature, or the MAF signal voltage could be skewed toward a lower voltage.

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    Lar_Arr2, August 02, 2013, 05:20
     Rookie

    Thanks for the feedback.

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    lightsaber, August 02, 2013, 07:47
     Technician

    You are very welcome! A lean condition could mean the O2 sensors are picking up unburned oxygen from a cracked, or loose air inlet tube from the air box to the throttle body that the PCM does not know about as it would enter after the mass air flow sensor. Also try cleaning the MAF sensor with MAF sensor cleaner from the auto parts store.

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