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The "Check Charging System" warning that won't go away...

Discussion in '2nd Gen - 2003 - 2006' started by bgrattan, Jul 30, 2020 at 12:33 AM.

  1. bgrattan

    bgrattan Member

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    Update, I pulled the alternator out again (by the way, is there a way to get it out without taking off the radiator hose and spilling some anitfreeze) and checked the three-pin plug, blew it out with an air compressor, reconnected, and confirmed the positive voltage connection was nice and tight. I also trace the signal wire to another plug and cleaned that one.
    All this had no effect.
    But, I was able to take it on a four hour drive with no problems at all--voltage stayed between 13.8 and 14.2 with brights on.
    The warning still comes on every time I start the engine though. I'm going to have to check all the fuses and connections other than right at the alternator.
     
  2. Hamfisted

    Hamfisted Full Access Members

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    Do you remember what brand of alternator you used? A lot of people have this problem with the cheaper brands like Advance Auto and such. Just wondering. Like they rebuild the alternator as far as brushes and bearings, but skimp on the circuit board that communicates with the PCM.
     
  3. thesavo

    thesavo Full Access Members

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    Here are some excerpts from the 2005 Service Manual DVD. It's not the same year as yours, but should be close enough. It would appear that the generator PCB communicates with the PCM with Pulse-width modulation. That is harder to get a reading on. You could check that you have good continuity with the generator/PCM pins. The PCM uses a serial bus to talk to the Instrument cluster.

    1. Charging system diagram.
    2. Ford ED/ED Diagnostic manual for the charging system explaining where to look for issues based on the DTC for P0622.
    3. Pin out diagram where the Generator signal wires terminate at the PCM.

    Attached at the bottom
    1. references the PC/ED manual. That has a further entry for P0622. This references another set of instructions, called HY.
    2. Workshop manual for the charging system.

    I hope some of this info is helpful.


    2005-exped-chargin.png

    2020-08-01 09_10_58-2005-exped-chargin-1.pdf - Adobe Acrobat.png

    2005-expb-c175b_chargin.png
     

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    Last edited: Aug 1, 2020 at 3:09 PM
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  4. TomB985

    TomB985 Full Access Members

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    Good information from the Savo, I've attached the relevant service manual info from the 2006 manual.
     

    Attached Files:

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