C15 loping like it has a cam

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Creswell81, Jan 31, 2022.

  1. Jan 31, 2022 #1
    Creswell81

    Creswell81 Bobtail Member

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    Apr 7, 2020
    North Carolina
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    I have a 2003 peterbilt 379 with a c15. The check engine light comes on in the last 4 gears when it's about time to shift gears and when I shift to the next gear it blinks 2 times and goes out. Only seam to do this under a load.
    Any idea what the prob is
    Also the flash code is 25 when I check the codes.
     
    Creswell81, Jan 31, 2022
    Creswell81, Jan 31, 2022
    #1
    blairandgretchen Thanks this.
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  3. Jan 31, 2022 #2
    little cat 500

    little cat 500 Road Train Member

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    Jan 17, 2010
    Abbottstown PA
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    Code 25 is a boost pressure sensor fault.I would inspect the plug for corrosion and make sure the wires are not rubbing no where. If all that is good, it is more then likely your sensor bad.
     
    little cat 500, Jan 31, 2022
    little cat 500, Jan 31, 2022
    #2
  4. Feb 1, 2022 #3
    DDguy

    DDguy Light Load Member

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    Apr 21, 2020
    Ont. Canada
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    How long have you had this truck ? does it possibly have the boost sensor mod resistor in it ? basically telling the the ecm the boost is to high ?
     
    DDguy, Feb 1, 2022
    DDguy, Feb 1, 2022
    #3
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