M1083 CTIS ECU issue

[Grimbo]

I have trolled through the forums and manuals, and cant find solution. I ared all the tires up to 50psi with external source, as all four of the lights were flashing. After airing up, the HWY light would flash and then go solid as expected, but I cannot get any response from any other button pushing, ie, sand mode or emerg mode etc. It does not respond at all. With the system powered up, I remove the breaker/fuse and let sit for a few minutes and then reppower it, and it has the same result. Anyone have any input before I go and buy a new controller which may or may not fix the issue. Thanks

 

[Ronmar]

Are y0u sure the wet tank pressure switch is reliably going over 117 PSI the switch closes at 117 and opens again at about 89 PSI to report tank/supply status to the controller. I don’t think it is going to respond until it sees that tank switch close...

 

[Grimbo]

Are y0u sure the wet tank pressure switch is reliably going over 117 PSI the switch closes at 117 and opens again at about 89 PSI to report tank/supply status to the controller. I don’t think it is going to respond until it sees that tank switch close...

Thanks for the reply. Yes, tanks are up on pressure, once they reach pressure I can hear the solenoids and then the ECU goes from flashing to solid. See the video I took re. https://photos.app.goo.gl/RWstnvxJEvaoCDsT6

 

[Ronmar]

Thanks for the reply. Yes, tanks are up on pressure, once they reach pressure I can hear the solenoids and then the ECU goes from flashing to solid. See the video I took re. https://photos.app.goo.gl/RWstnvxJEvaoCDsT6

yea, that sounded like it was doing a pressure check(seals system, gives a shot of air to open wheel valves, reads pressure sensor, then vents system to close wheel valves) And it won’t do any of that till the pressure switch sees 117 on the wet tank.

The system is twitchy on purpose so it will fault at the drop of a hat before it inflates or deflates incorrectly. Yours apparently sees what it needs to satisfy highway mode. Have you tried manually inflating to a different pressure, say 40PSI and seeing what it does? Also if you run it for a while, the system should automatically check pressure like shown in the video, every 15 minutes...

The fact that it won’t select another mode could be a bad keypad. You can remove the top cover and frame with a small Allen wrench. I cannot recall if the keyboard has a ribbon connector under there or the keyboard ribbon cable just runs into the potting compound to connect to the circuit board inside. I have only pulled one apart once when I gutted my failed one(5 solid lights) to convert the system to manual control... But you certainly can’t hurt it pulling the keyboard frame off for a look...

 

[Grimbo]

yea, that sounded like it was doing a pressure check(seals system, gives a shot of air to open wheel valves, reads pressure sensor, then vents system to close wheel valves) And it won’t do any of that till the pressure switch sees 117 on the wet tank.

The system is twitchy on purpose so it will fault at the drop of a hat before it inflates or deflates incorrectly. Yours apparently sees what it needs to satisfy highway mode. Have you tried manually inflating to a different pressure, say 40PSI and seeing what it does? Also if you run it for a while, the system should automatically check pressure like shown in the video, every 15 minutes...

The fact that it won’t select another mode could be a bad keypad. You can remove the top cover and frame with a small Allen wrench. I cannot recall if the keyboard has a ribbon connector under there or the keyboard ribbon cable just runs into the potting compound to connect to the circuit board inside. I have only pulled one apart once when I gutted my failed one(5 solid lights) to convert the system to manual control... But you certainly can’t hurt it pulling the keyboard frame off for a look...

Yes, I will pull the cover off and look closer. If it is the controller that would make it simple. Thxs

 

[Grimbo]

Ok, finally got back to this. I took the CTIS control face/cover off, not obvious damage. Aired the tires with shop air to 75psi, and the hwy led stays lit, but cannot get any other button to function. Dropped tires to 50psi with same result. Google link shows vid of the lights and controller https://photos.app.goo.gl/6LN5fgSaneX58i856
I cant think of anything else to look at before buying replacement controller, which gives me great pain.

 

[Suprman]

I have replacement controllers

 

[Grimbo]

I have replacement controllers

Ok, are they new/used. If used are they working 100%. Also price? Thxs

 

[Suprman]

What year is your truck? First gen can use any controller. 3126 a1 needs a second gen controller and c7 trucks require a 3rd gen black one.

 

[Grimbo]

What year is your truck? First gen can use any controller. 3126 a1 needs a second gen controller and c7 trucks require a 3rd gen black one.

It’s M1083 10/1996 manufacture

 

[Suprman]

Got this one here. Good used second gen 400 shipped. Set to higher pressure and overspeeds but sometimes the older trucks wont pressurize as high as the setting. I can set the pressures to whatever you want.

 

[Grimbo]

Got this one here. Good used second gen 400 shipped. Set to higher pressure and overspeeds but sometimes the older trucks wont pressurize as high as the setting. I can set the pressures to whatever you want.

Ok. Pressures look good. 90% of my driving is off hwy. let me know how to proceed.

 

[Ronmar]

I cant think of anything else to look at before buying replacement controller, which gives me great pain.

Yea, that great pain part weighed in my decision to go manual, that and it wasn’t something I really wanted automated(i’m a control freak I guess). Superman is your guy for a replacement as he can configure it anyway you want it. The higher pressures for highway are good for tire wear and stbility. If your truck has trouble reaching them it is most likely just leaks in the system. More pressure = more flow thru any leaks…