Rough Idle and P1242 Code after some maintenance

Discussion in 'Starting Line - New Member Introductions' started by Texas4Life, Feb 26, 2017.

  1. Texas4Life

    Texas4Life New Member

    Feb 25, 2017
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    So I did some maintenance on my 04 mini cooper s which included: Supercharger oil change, water pump, water pump flange, crankshaft position sensor o ring, oil dipstick o ring. So after putting everything back together and starting it for the 1st time I get a code P1242: Secondary Upstream Manifold Air Pressure Sensor Signal Too High in Deceleration. And the idle is fluctuating between 1200-1600 rpm.

    I went looking around I know one of the things too look at is the bpv, which I did and once the engine was up to temp I could clearly see the lever moving back and forth. I also looked at the intercooler boots and they look fine. I also sprayed some of the vacuum hoses, to see if i could get a change in rpm and I didn't et any change. But to be fair the idle is fluctuating so much it's hard to tell. The other thing I did is I unplugged the front MAP sensor, the one by the intercooler, and the idle dropped back down to 900-1000 rpm. Not sure if that's normal or not. Any ideas?
     
  2. MCS02

    MCS02 Moderator
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    Jul 31, 2009
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    After doing some work on my 02 I got the same code and found this unplugged, But my idea was steady.
     

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  3. Texas4Life

    Texas4Life New Member

    Feb 25, 2017
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    Ok for anyone that has this issue it ended up being the vacuum hose under the MAP sensor had broken.
     
  4. 00Mini

    00Mini Well-Known Member

    Feb 24, 2013
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    Good to hear that the problem has been corrected and thanks for the update.
     

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