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dodah457 8/11/2012
2009 Mini Cooper Base 4 Cyl 1.6L - Engine
how do i fix trouble code p2270cnf
1 Answer
  • Jimm
    Jimm 8/11/2012
    P2270 = 02 Bank 1 Sensor 2 signal stuck lean

    faulty O2 sensor

    The most common issues for lean codes are:

    1. Vacuum leaks - check for failed or loose vacuum lines, leaking intake gaskets, intake air tubes loose or any other source of un-metered air leaks (leaks after the Mass Air Flow Sensor)
    2. Restricted fuel filter or bent/pinched fuel system lines
    3. Incorrect input from other sensors, such as the Mass Air Flow Sensor, which may not always drop a separate code
    4. Engine misfire - Yes I know this one may seem weird. You might think that if there is a misfire then you will have all that unburned fuel and it should read rich; right? Well the O2 sensors read only oxygen content in the exhaust, so if you have all that unburned fuel from incomplete combustion then, you guessed it, you also have all that unburned oxygen. High O2 content in exhaust equals a lean reading!

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