M939 CTIS Pneumatic Controller

[sassriverrat]

Good Evening,

I've successfully had my CTIS working for 4 years....until today. I've been through leaks, faults, and dust and today it bit me. I had a handle-mount break in the winch control pedestal. Right before pulling it off, I started the truck and got 5 lights. Trying to override and force a low tire to fill, I noticed the valve controller was dumping air in the cab. This prompted me to remove the Winch control pedestal (so I could properly weld it) and looking at the CTIS pneumatic valve controller, everything looked fine. When the unit takes a "sample" of air, it blows all the air out the bottom, side port. There's nothing there.....it appears that a hose should have been in it, but right now there's just a threaded hole.....am I missing a fitting? I have two hoses (one black, one yellow) on top of the unit and a blow off or overpressure valve on top. I can't believe there would be an opening on this system for dust to get into.


Any have a picture of the unit mounted in the cab?

Thanks

 

[sassriverrat]

Bump

Picture?

 

[Jbulach]

IIRC the yellow and black lines are the only two. I’ll try to remember to get a picture for you.

 

[sassriverrat]

Huh. That’s what I thought. Anything in the port in the bottom of the controller (if the black and yellow lines are on “top” facing you)? The port seems very clean and I don’t remember seeing it before- makes me wonder if there was a plug in it. It’s peeing the air out of it there.....

 

[sassriverrat]

So maybe you guys can help-

5 blinking lights on CTIS controller, sounds piss poorblowing air offin cab controller valves. I tried throwing a plug in the bottom air vent (bottom ofcab controller where it looks like it’s missing) and that went to four lights briefly and then back to five. I’ve never (in my memory)had this thing vent through the cab relief valve. Ideas here?

 

[ABecker]

Mine was doing the same thing. I found the Spicer CTIS Trouble Shooting Guide and it said to push the run flat button. After letting it run for 5-10 minutes push HWY and it should operate normally. Here is the Spicer Guide

http://media.spicerparts.com/cfs/files/media/WQ86BTpCnbQ52SaSq/axts-0015.pdf?token=eyJhdXRoVG9rZW4iOiIifQ%3D%3D&store=original

 

[sassriverrat]

Mine was doing the same thing. I found the Spicer CTIS Trouble Shooting Guide and it said to push the run flat button. After letting it run for 5-10 minutes push HWY and it should operate normally. Here is the Spicer Guide

http://media.spicerparts.com/cfs/files/media/WQ86BTpCnbQ52SaSq/axts-0015.pdf?token=eyJhdXRoVG9rZW4iOiIifQ%3D%3D&store=original

I’ll go back through the guide but unfortunately hitting “run flat” was part of the regular routine because I’ve got one tire that likes to leak a bit.....

I think this is now deeper down.

 

[bachman502]

PM sent Sassriverrat

 

[Andyrv6av8r]

I would look for loose/leaky wheel valves and tear apart the PCU. It's easy to do and gives you the chance to check the solenoids and coils.

 

[sassriverrat]

I’m going to get into the PCU again. I’ve been into it once and didn’t get solid readings on two of the solenoids, but I was in a rush. The middle one was fine at 51.
Wheel valves are all good minus one that’s had a known leak and the minute leak wasn’t causing an issue before.