Need help!! Freightliner with Cat 3406e got me stumped

Discussion in 'Trucks [ Eighteen Wheelers ]' started by 2tonchevy, Sep 6, 2022.

  1. 2tonchevy

    2tonchevy Bobtail Member

    Joined:
    Sep 12, 2017
    Messages:
    38
    Thanks Received:
    12
    0
    Hopefully somebody here can help me:

    1998 cat 1lw 3406e in freightliner classic

    No start

    Ecm will not power up

    power supply and grounds have been verfied and load tested (keyed hot, constant hot, and ground)

    Ecm has been bench tested and ran on boyd caterpillar dyno in corbin ky and is good

    Check engine and engine stop lights do not come on on dash but i have confirmed that they do work (bulbs not bad and wires are good)

    What am i missing???
     
  2. Big Road Skateboard

    Big Road Skateboard Road Train Member

    Joined:
    May 2, 2021
    Messages:
    6,505
    Thanks Received:
    36,472
    0
    @2tonchevy You say load tested. Have you checked ECM power and ground while it's plugged in key on, or only after removing the harness?
     
    Last edited: Sep 6, 2022
  3. 2tonchevy

    2tonchevy Bobtail Member

    Joined:
    Sep 12, 2017
    Messages:
    38
    Thanks Received:
    12
    0
    Yes

    i tried a good spare ecm and had mine checked at CAT.
     
  4. 2tonchevy

    2tonchevy Bobtail Member

    Joined:
    Sep 12, 2017
    Messages:
    38
    Thanks Received:
    12
    0
    I load tested the hots and ground for ecm power supply to 10 amps.
     
  5. Big Road Skateboard

    Big Road Skateboard Road Train Member

    Joined:
    May 2, 2021
    Messages:
    6,505
    Thanks Received:
    36,472
    0
    Yes to which one? Did you verify ECM power and ground with the ECM plugged in?
     
  6. 2tonchevy

    2tonchevy Bobtail Member

    Joined:
    Sep 12, 2017
    Messages:
    38
    Thanks Received:
    12
    0
    If i understood him...The tech at cat told me i had to have two 5 volt datalink inputs to the ecm in order for it to power up. I had never heard this. But i do not have ANY voltage or grounds on the datalink pins on the harness coming from the truck.
     
  7. 2tonchevy

    2tonchevy Bobtail Member

    Joined:
    Sep 12, 2017
    Messages:
    38
    Thanks Received:
    12
    0
    Yes to both
     
  8. Big Road Skateboard

    Big Road Skateboard Road Train Member

    Joined:
    May 2, 2021
    Messages:
    6,505
    Thanks Received:
    36,472
    0
    Do you have sensor voltage supply?
     
  9. Big Road Skateboard

    Big Road Skateboard Road Train Member

    Joined:
    May 2, 2021
    Messages:
    6,505
    Thanks Received:
    36,472
    0
    Have ypu checked specifically for an ignition power feed? Not constant battery supply
     
  10. 2tonchevy

    2tonchevy Bobtail Member

    Joined:
    Sep 12, 2017
    Messages:
    38
    Thanks Received:
    12
    0
    I have not pinned the sensor side of the ecm. Just been focusing on getting it to turn on lol the guys at cat that ran my ecm on their dyno instructed that i only needed pins 4, 5 and 6 verfied and datalink voltage to turn on the ecm.

    I admit that i do not know much about how this ecm works or how the "datalink" interacts witj the ecm. But im trying lol
     
    Oxbow Thanks this.