» » »

Ford Q&A

Ask Your Question

2004 Ford F-150 Heritage Question: check engine light

 

Question

joe83, 4.2L V6, Killeen, TX, April 04, 2011, 15:22
 Rookie

evertime its cold outside my check engine light comes on and the scanner reads system too lean bank 2 ,evap system not ready not vacuum leaks in the engine changed gas cap

1 Answer
Flag This
  • Answer #1

    DaveJHM April 05, 2011, 01:13
    Profile_thumbnail
     Master

    If it's bank two only - you could actually have a faulty oxygen sensor - pre cat. I would recommend monitoring fuel trims to see if the oxygen sensor on bank 2 is operating differently than bank 1.

    Flag This
  • Reply

    Visitor, April 06, 2011, 13:16

    all the O2 sensor are working right and at first it said bank 1 sensor 1 engine runing lean i had replaced that one but they are all good know can it be the IAT Sensor

    Flag This
  • Reply

    DaveJHM, April 06, 2011, 21:04
    Profile_thumbnail
     Master

    I can't draw any correlation from a lean code to an IAT sensor failure.

    Bank one sensor one would be P0171. But you stated your concern is bank 2 (P0174).

    When you get lean codes, you monitor fuel trims and see how the sensors switch.

    Flag This
  • Reply

    Visitor, April 13, 2011, 14:58

    the code came back on and my fuel trims read st1-13.2 / st2-13.2 Lt1-17.1 / Lt2-26.5 when it was 59F out side and it come and the code now is P0174 do you think it can be the Dpfe sensor or the fuel pressure regulator

    Flag This
  • Reply

    DaveJHM, April 13, 2011, 20:50
    Profile_thumbnail
     Master

    Lean bank 2 (P0174) cannot be caused by a DPFE sensor or a fuel pressure regulator.

    Again, with one bank lean code only, I would lean towards checking the wiring at the bank 2 pre cat oxygen sensor.

    When I suggested monitoring fuel trims, I was suggesting check to see if the sensors both switch evenly. You can do a graph read out that will look like a wavelength. I'm betting bank 2 pre cat oxygen sensor is more flat lined.

    Reply
    Flag This
Answer Ranks