Recent content by Stellaevil

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    M923A2 CTIS Problem

    Great to hear, we hope to have some better wheel valve parts coming soon that will solve the old cold temperature issues.
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    M939 CTIS Reprogram, Anybody Done It?

    Some green modules after 1998 can communicate with the tool on a J1587 link. All black modules should be able to use a CAN link.
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    LMTV CTIS UPGRADE

    Dana will be releasing a new CTIS Wheel Valve design that will be compatible with the LMTV systems. The valve will only be sold to OEM for current production. However if there is enough interest we could market a rebuild kit. The advantage of the replacements parts is a new diaphragm that will...
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    M923A2 CTIS Problem

    Sorry I don't check the site as often as I should. One scenario I can think of is that the tires were at the highway pressure and then went up due to the heat in the tires. When the system did a pressure check you may not have noticed the highway light flashing for a couple seconds. When the...
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    M923A2 CTIS Problem

    The CTIS will only fault out on the pressure check if the pulse of air drops to below 5.0 psi. That is a pretty big leak. Hard to hear with the engine running so hook up shop air and run the system. If you don't have enough pressure >120 psi to close the switch, disconnect and short the harness...
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    M923A2 CTIS Problem

    FYI, if you are new to these CTIS threads; I still work for the company who designed and manufactures these systems, 30 years now. 939, LMTV, MTVR, and JLTV. Happy to help those who serve. Air seal leaks; while the system is inflating, check the axle vent tubes for pressure build up. 5 lights...
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    M923A2 CTIS Problem

    Sorry need to be more clear. 5 light fault before the pressure check = Electrical short or open, after the pressure check = <5 psi tire pressure reading. If the system starts to inflate or deflate and there is a problem it may take 20 minutes or more for the system to see there is a problem.
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    M923A2 CTIS Problem

    You can clean all the parts with a mild solvent. If you then massage the rubber diaphragm with oil it may become playable again and work. You may be able to order the Diaphragm; Dana or Spicer 599805 from a truck parts dealer.
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    M923A2 CTIS Problem

    Any blocked air passage could only cause a higher than normal tire pressure reading. If air gets trapped in the system after a Vent, the wheel valves may not close properly and start dumping air.
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    M923A2 CTIS Problem

    I apologize, CTIS threads have been slow lately so I do not check as often. Duck bills are not necessary if the CTIS functions on a regular basis. They can be a real problem in very cold temps because they stick shut or or don't open far enough. A system that faults out after a pressure check...
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    M923A2 CTIS Problem

    With some creativity you can adapt the FMTV wheel valve to the 939.
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    M923A2 CTIS Problem

    Your best bet might be to update the valves and hoses the FMTV version and get rid of that crappy metal tube.
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    M923A2 CTIS Problem

    The larger wheels will only be a problem during an inflation. If the compressor output is low such as at idle the system may log a slow inflation fault. Just run the engine at high idle or higher.
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    M923A2 CTIS Problem

    The sensor in the wet tank is really just a switch. It should close around 115 psi and open back up when it drops to 85 psi. Even if the switch is closing the wire going back to the ECU may be open. Disconnect the switch and short the pins on the harness side, the PCU should start clicking...
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    M923A2 CTIS Problem

    Remove the the duckbills from the the QRVs see if that fixes the issue. They need to be open to properly close the wheel valves. 5 lights on power up; Electrical issue 5 lights after the first pressure check; large air leak, check the axle vents for the seals leaking. 5 lights after the system...
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