Another CTIS Problem!!!!

[jrosbo]

I have read other posts. I have read the TM's. I've read the CTIS manual and none of them have the problem that I'm having. I've tracked air lines, checked valves and I have no clue. When you get the system up to pressure the PCU valve just starts making a constant pfft pfft pfft pfft sound. The controller just flashes one light and never goes into error mode. You can change modes and the controller light will move to which ever button is pushed. The PCU will pause a second then go back to the pfft pfft pffft sound. I'm at a loss please help. I'm thinking the PCU is bad, but before I spend $200 on a new one what do you guys think? This is on an M923A2.

 

[1 Patriot-of-many]

Sounds like it's working to me? You'll hear noises as it cycles and fills low tires. When the tires are fully aired it will stop and the light will remain solidly lit. I couldn't play the movie, just going by your description.

 

[dmetalmiki]

Why they use this system baffles me, russian trucks have never experienced all the problems U.S. trucks seem to experience.

 

[tim292stro]

CTIS works by cycling though all of the wheel-ends one at a time. This gives the pressure a chance to settle on one wheel-end so it can be measured while the others are inflated/deflated. Sounds like you have one that it's filling... IIRC the flashing LED just means it still hasn't gotten to that set-point.

 

[jrosbo]

Tires are up. The system worked fine for about a year so I know what it sounds like when its working properly. I have left it sit for a while and eventually it just stops. But the light stays flashing.

 

[1 Patriot-of-many]

Tires are up. The system worked fine for about a year so I know what it sounds like when its working properly. I have left it sit for a while and eventually it just stops. But the light stays flashing.

So it stops cycling, but the light continues flashing....hmm got me, that is strange.

 

[Coffey1]

The pcu needs to be taken apart and cleaned and lubed.
The valve is not closing 100 per cent

 

[jrosbo]

Ok I went back out and this is what I discovered, it cycles pretty fast, I took the line off that goes to the wheels and you could not hold your finger over the line each time it cycled. Plenty of air, way more than the 12psi check. It also blows air out the whole on the side of the cover that is over the solenoids. Took the PCU apart, clean as a whistle, valves moved freely. Checked ohms on the solenoids two at 47 one at 25. From reading other posts the 25 is bad. The bad one was the C. I know you can replace the solenoid but I think I will replace the PCU and keep this one for parts. But wouldn't this throw up an error on the brain box. Do you think this could be the problem? One other thing, how do the solenoids actuate the valves they are not connected? Magnetic? I wish I knew how to post video for everyone to watch, if you saw it you would know it's not right. I can watch it with Windows Media Player if that helps.

 

[1 Patriot-of-many]

I bought a take off from someone parting out a truck, told it was not working to use a solenoid. Turned out it was a good PSU! I ended up sending him a little more cash cause I didn't feel right. Yeah electro magnetic.

 

[Andyrv6av8r]

Swap out the PCU. It will fix it.

 

[jrosbo]

I ended up changing out the solenoids after a parts source on here mysteriously ran out of the PCU's once they realized they had been selling them for the wrong price and giving me the run around. I changed them with the Peter Pauls that were listed on another thread and it fixed the problem. Also the tires seem to inflate faster now and the whole system operates much quitter except for the goose honk at the end.

 

[charger53]

I don't want to hijack the thread, but since it is a CTIS thread, Does anyone know if the air release valves where it splits at the axles can be rebuilt? My rear one leaks, lets the whole system flatten all the tires unless I unplug it.