C15 MBN flash code question

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Padwalz, Jan 12, 2019 at 9:22 PM.

  1. Padwalz

    Padwalz Bobtail Member

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    Hi everyone, new to the forum although I've been lurking a lot.
    Got an MBN with a check engine light that comes on after about 8 hours of running, flash code 26 ( atmospheric pressure signal issue) and code 8. I've searched the net all day and I get nothing on code 8. I didn't know cat had single digit flash codes.
    Anyone have any ideas or thoughts?
    Thanks in advance
     
  2. Muddydog79

    Muddydog79 Medium Load Member

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    Have you rechecked several times to make sure its code 8? Never heard of it.
     
  3. Padwalz

    Padwalz Bobtail Member

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    Yes 100%.
    Code 26 first than code 8.
    I don't know if I can post videos here but I will record it on Monday.
     
  4. Muddydog79

    Muddydog79 Medium Load Member

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    10-4. Reason i asked is because i have screwed up a time or two trying to read mine.. blink one to many times, and you miss a pause, or a flash. I would take it to a dealer mechanic and have him put a computer on it and maybe reflash it if he sees something crazy like code 8. I had a bunch of codes start coming up, and disappearing on my mbn, and after about a year of that happening, the engine suddenly lost pulling power and started sputtering. It would idle fine, but would not go threw any gears wothout a terrible miss. Long story short, the ecm took a dump. Got a new one, havent had those codes pop up since. May be something going on in your ecm.
     
  5. McMahons Trucking

    McMahons Trucking Light Load Member

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    Do you have good boost pressure? If the atmisperic pressure sensor doesnt sense boost it will go into some sort of derate mode
     
  6. Diesel Dave

    Diesel Dave Last Few of the OUTLAWS

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    Why not change that sensor ? When my 5EK threw that code, I changed that sensor. Problem solved.
     
  7. Cam Roberts

    Cam Roberts Heavy Load Member

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    Sorry but cat uses 2 digit codes. You have an error somewhere or you reading it wrong. If not, you would be the first case in cat history so I’m thinking you have a computer malfunction. Unless it’s code 44
     
    WordHungry Thanks this.
  8. Muddydog79

    Muddydog79 Medium Load Member

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    I dont see a code 44. Only other code i see that it could have been mistaken for is 6-2, low coolant level.
     
  9. Diesel Dave

    Diesel Dave Last Few of the OUTLAWS

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    Don’t you read the codes thru the cruise control? You hold the increase or decrease toggle switch for a few seconds and you get 2 sets of flashes ?
     
  10. Muddydog79

    Muddydog79 Medium Load Member

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    Yes
     
    Diesel Dave Thanks this.
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