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PO171 and PO420 codes

Paul1234
Paul1234
in Ford Focus Club

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hi all im new here so hope im posting in the right place. First off i have recently brought a mk2 focus 1.6 petrol which is having a few problems, the car seems to run and drive fine other then on the odd occasion when it starts to die, the car will start straight back up without any problems, ive had the eml checked and its giving out 2 codes, the first being PO171 and the second is PO420, if anyone can give me a bit of help as to where to start looking i would be very grateful, thanks Paul.

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    The link below outlines all the DTC that you can find on Fords and other vehicles:
     


    Your codes relate to:

    • P0171 System too Lean (Bank 1)
    • P0420 Catalyst System Efficiency Below Threshold (Bank 1)

    What this is likely to be is the MAF Sensor being dirty or malfunctioning. You can search this forum for the exact location for your vehicle and how to go about cleaning it.

  • Quote
    • Author

    Ok thanks dansallis, i will investigate further and clean maf sensor, and post back results, thanks again. Paul

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