Looking for Chip S.

Discussion in 'Freightliner Forum' started by QUALITYTRUCK, Jul 18, 2014.

  1. QUALITYTRUCK

    QUALITYTRUCK Road Train Member

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    Jun 14, 2009
    romulus,mi
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    Hey Chip.Got a 2006 columbia/series 60/eaton smartshift/eaton vorad."no data link"appears and i loose dash gauges.j1939 pins c and d 120 ohms.need to be at 60ohms.things i have tried with known good parts from sister truck.terminating resistors at driver frame rail and at frame mount abs module.abs module.aux.p.d.m.engine e.c.m.vorad module.i cannot get abs light to go out ever.laptop meritor gives me active fault for j1939 hi/lo can open.1939 and 1708 wires from abs module to connector under driver seat all good.please help.thanks.
     
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  3. Chip S

    Chip S Light Load Member

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    May 27, 2013
    Texas
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    Quality,

    I think you may have two seperate issues, as you have issues on both datalinks. For the j1939 issue.. You are missing a terminating resistor. With having a frame mounted abs module, vorad, and an autoshift, they could be at a few different places. IIRC the resistors should be at the abs module (near the battery box) and near the TCU, Also could be under the surge tank. Both need to be 120 ohms. When you disconnect each one, I would ohm my green and yellow wires to another green or yellow wire to the backbone, and make sure you done have an open.

    For the gauge and no data link problem. The icu and engine talk only through j1708. The icu doesnt talk on 1939 until 2010. The easiest way to diagnose the 1708 issue is to wait until the gauges act up. Remove the driver side threshold and panel under the b piller. under that you will find your 1708 rear junction block. Disconnect each connector into that junction block until the gauges come back up. If the gauges talk, then connect it back in to make sure they drop out. If they dont ever come back, you have to move to the dash. Remove the cup holder and look under the dash, you will find another junction block. Continue to remove the connectors one by one. Once the gauges work, you have found the faulty leg on the databus. Each leg goes to individual ecu's and are labled j1587e- engine, j1587d- diagnostic connector.. ect..
    Another good test to troubleshoot the j1598 datalink is to measure voltage with your key on between pins F and G on the 9 pin diagnostic connector. You should be getting 2-5v (not steady). If it shows 0-1v you have a shorted datalink.

    also, what is the code for your abs light? Do your modulator valves pop at initial key on?

    I kinda rambled on, If you have any questions let me know. Post what you find!
     
  4. QUALITYTRUCK

    QUALITYTRUCK Road Train Member

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    thanks for reply. active fault for "j1939 can bus open" is the code for abs.all modulators pop at key on.1939 wires good from abs module to floor pass thru connector to b pillar.you say that there is a third resistor near trans. ecu?i only checked the other two(under surge tank/under battery box)pins c and d should ohm at 60 correct?it reads 120.for 1708 issue voltage at F and G both add up to 5v.(1.3 and 3.7)great idea to unplug one by one when happening.did not know about junction under cup holder!great info to keep me going.am confident i will find this problem (on Monday!) with guy's like Chip helping.
     
  5. Chip S

    Chip S Light Load Member

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    May 27, 2013
    Texas
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    There are just two terminating resistors on the j1939 datalink. Freightliner wants to put them on each side of the backbone. The only way to do that is to have different places to install the resistors depending on the application and options installed. Somewhere there is an open in that datalink. I would disconnect the abs ecu and measure resistance across the j1939 wires at the itself (should be 60 just like diagnostic connector). Basic rule of thumb on the datalink.. if there is one working resistor you will get 120 ohms, 2 good resistors you get 60 ohms and three good resistors you get 40 ohms. Hopefully you wernt spending all morning looking for that third resistor :/.

    If I were you, I would disconnect the resistors and measure A. the resistor itself (should get 120) and the harness that plugs to the resistor (with the resistor disconnected) and you should get 120 ohms. Im going to guess you are going to only get 120 ohms at one resistor, and you have an open somewhere. Double check all the splices in the 1939 backbone, those pins are pretty weak and like to break/corrode. B. Disconnect the abs module, ecm, and TCU and make sure you are getting the same resistance values as you are getting between pins C and D at the diagnostic connector.

    Have you gotten the gauges to mess up again to troubleshoot your j1587/1708 issue? Is there a qualcomm or peoplenet installed? Is there a chance that there is factory wiring at the top of the cab that has some corrosion? Also check under the bumper and make sure the vorad harness isnt rubbing the bumper support. Hopefully you can get it to act up and you can disconnect at both junction blocks. I find that to be the best test because you done really disturb any wires during checking.
    Good luck
     
    QUALITYTRUCK Thanks this.
  6. Semi Crazy

    Semi Crazy Road Train Member

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    May 13, 2011
    Middle Tennessee
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    Oh my goodness! Data links and modulators... my old truck will never have those problems.

    Good luck with all that. Chip sounds like a good feller.
     
  7. QUALITYTRUCK

    QUALITYTRUCK Road Train Member

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    romulus,mi
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    Got it!j1939+ wire in cannon connector for abs in b pillar was not locked in,so when you would plug in connector it would not make connection,just push pin back into connector body.gauge issue was 2 "scotch locks" ,under passenger kick plate,left over from qualcom install.thanks to Chip for helping.
     
  8. Chip S

    Chip S Light Load Member

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    May 27, 2013
    Texas
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    Thats great! Good find!
     
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