CTIS 5 flashing lights, no air leaks, no mechanical faults.

[MtnSnow]

Yep with what your seeing I'd bet that you have 1 or more of the solenoids have gone bad.

 

[Alexsha]

I was able to get in there this morning and check the resistance on the PCU solenoid connector. A-E deflate is good at ~45. Both B-D control and A-F supply give 0.L readings so it looks like I'm in the market for 2 solenoids. From other threads on here, it looks like a Peter Paul 5C-13-K24 PPF solenoid is a good replacement. I've found these on an online auction site as well as plccenter.com. I'm thinking of going with plccenter.com as they also have replacements for the water separator on the input for the PCU and I need that as well.

Does anyone know a better part # for a replacement solenoid?

 

[Vette427]

Guys,

I'm working through a similar problem. Initially had 5 instant flashing lights and the system would do nothing other than a pressure click at the in-cab controller. Found schrader valves in the flexible lines at all 6 wheels (diagnosed by being unable to fill/check air pressure at the wheel valve). Removed schrader valves. Aired all tires up to 70 psi.

Now I'm getting a little action. The system acts like it wants to work. The in-cab controller cycles and I can hear the valves at the rear making a honking sound as well as a loud whistle (very noisy). After a few tries with this, the system goes back to 5 flashing lights. I've got 130 psi of system pressure in both tanks and I didn't have any leaks with the schrader valves installed, so I don't think it's an issue with any of the tires or rims. I could have an issue with one of the wheel valves now that they have pressure, but I don't think this is the case since I have 5 flashing lights.

Thinking of bypassing the tank pressure switch (is there any pictures of this switch or a picture in the TM?) or maybe an issue with the air dryer or one of the rear dump valves? The honking/whistling is coming from the rear of the truck near the back axles. I'm not sure that one of these not functioning properly would cause 5 lights.

The system has not been active for a number of years, so I'm trying to get everything working. We're using this for a backup delivery vehicle for our business. It would be nice to be able to air down the tires to make it easier to load/unload at the dock.

 

[Suprman]

Loud noisy honking siren sound is bad hub seals. Inexpensive part but expensive labor to pull axle shafts to replace seals.

 

[Vette427]

Suprman, thanks very much for the prompt reply.

Would I have issues with hub seals when the schrader valves were in place? The truck has always been good at holding air. No issues with tires leaking down.

Also would hub seals cause 5 blinking indicators instead of 4?

As an update, the system did air down. I had 70 psi all around and I now have 50 psi +/- 5 psi all around. So it did dump some air evenly at all 6 wheels when I pressed the emergency button along with the run flat button.

Thanks again for the help that you've provided for all of us.

 

[Suprman]

You can put the Schrader valves back in and be fine. The system is sending air but since air is escaping thru bad hub seals, less than the intended pressure is reaching the wheel valves. It is enough pressure to hold the wheel valves open a bit and the system is dumping air. It just dosnt know any better.

 

[Coffey1]

Just to let every one know the only time a ecu is bad is when it has 5 solid red lights.
Then and only then is it toast.

 

[RedBlok]

Hey Guys, I have been following the different CTIS threads and I think this one is the closest to my problem. Driving back home on a 220 mile trip, my CTIS system started acting up at my fuel stop 60 miles from home. I was in the Truck stop parking lot when it happened. The Hwy light was blinking like normal, but then there was a loud squealing noise. IT lasted about 20 seconds. If I shut down the truck, it stopped immediately. It did it again two more time with about 20 seconds between events. Then the noise stopped and I had 5 blinking lights. I had good air pressure, tires were fully inflated and brakes worked well. I should have shutdown and disconnected the CTIS before heading home, but I did not have access to my laptop and the TM's. The unit flashed 5 lights the remaining 60 miles. I made it home ok. Later I drained the tanks and let the truck cool down, I went back started the truck. Air Pressure built up properly, brakes worked, but this time no flashing lights or any lights on the unit (Yes my headlights were on).

Jump ahead to the next day. Truck starts fine, air pressure builds properly, brakes work fine, all the tires are fully inflated but still no lights on the CTIS unit. I shut down, disconnect the CTIS, restart, shutdown, then reconnect the CTIS and start up - still nothing. No lights or anything.

I will say that I was transporting the truck back after swapping out the batteries. One of the connections came loose while I was driving and caused some arcing and a little smoke in the batter box, but that was quickly resolved. Not sure if that could have cause the problem. I was driving mainly 55MPH, but occasionally hit 60 due to highway traffic and trying not to get run down. I don't think that could be the issue.

I would agree about the bad hub seal, but the sound has stopped - if the CTIS is not working, does the CTIS stop sending air to the system, only trying to determine why the sound stopped. So far the tires have all remained inflated, but I will check their status again.

Any advice or thoughts? Also I can't find the Spicer/dana trouble shooting guide. can somebody post a link?

Thinking about just eliminating the whole CTIS system if I can fix it. I have looked at the threads on that too. The CTIS system is awesome while it is working.

Thanks and good night

 

[Alexsha]

When the CTIS s flashing 5 lights it has detected a major electrical or pneumatic fault and it shuts down completely. It will neither inflate or deflate.

Arcing in your battery box could definitely fry components in your truck. Might need to check wires, fuses, and whatnot.

 

[Goobs]

Dumb question here, but where is the fuse box in these trucks?

My CTIS has acted up in the past but I have a slow leak in the o ring in my front driver wheel that is causing the error.....everything else functions properly, I just don't have the nads yet to dismount the wheel and separate the wheel to replace the $2.00 o ring................hoping the people I meet at the meeting tomorrow may have some experience in that......

Goobs

 

[RedBlok]

So I checked the CTIS today. 5 lights flashing, so that is better than no lights (soldier B) told me he had the head lights on when they were turned off. System is fully pressurized. I tried pressing the HWY button (nothing ) and I tried pressing and holding the RunFlat Button (nothing). No leaking sounds inside the cab. I checked for any leaks either oil or air on each of the wheels. I need to try again when Soldier B or C are available to hold the button down while I walk around the truck listening for leaks.

I did notice one small leak is new. This is on the Right front wheel. When I got the truck the right front hub like this, but not dripping any oil. I had a M923A2 mechanic near Ft McCoy check the truck, he said just to watch it, but not to worry about it. I know it is only a small leak, but maybe this from the Hub Seal blowing.

Sorry - I can't get the file to upload. I will post a picture when I figure out how.

 

[RedBlok]

Dumb question here, but where is the fuse box in these trucks?

My CTIS has acted up in the past but I have a slow leak in the o ring in my front driver wheel that is causing the error.....everything else functions properly, I just don't have the nads yet to dismount the wheel and separate the wheel to replace the $2.00 o ring................hoping the people I meet at the meeting tomorrow may have some experience in that......

Goobs

Welcome to the CTIS party Goobs!

I'm am sure that you will get it figured out. These guys have always been helpful. Suprman knows his stuff well and has been very helpful to me in the past.

Redblok

 

[Alexsha]

RedBlok,
When you start the truck, does the CTIS selector blink highway?
One you reach 120psi, does it go to 5 lights without making any clicking noises in the PCU?

 

[RedBlok]

RedBlok,
When you start the truck, does the CTIS selector blink highway?
One you reach 120psi, does it go to 5 lights without making any clicking noises in the PCU?

I have to go back and check later this week. I remember in the past the PCU (on the floor behind the cover would make clicking noises once it got to 120). From what I remember today, it just goes to 5 blinking lights and stays that way.

Again, I have to go back to the storage lot later this week to check that out.

Rob

 

[RedBlok]

OK - I give up. I read Clinto's Tip and Tricks for uploading pictures, I follow the instructions to upload the pictures. When I click upload, nothing happens. I have the pictures on my local machine, I just can't get them to upload. Funny thing, I have uploaded pictures before without a problem.

Any suggestions?

 

[Alexsha]

Generally, if you have an air leak, you will hear something from the PCU. To detect an air leak, it has to at least try.
If you have an electrical issue, the PCU will never make a sound.

By what I've seen, the most common electrical issues are a dead ECU (5 solid lights or no lights) or a dead solenoid in the PCU (5 blinking lights with no sound from PCU).

Here's my thread on testing/replacing the solenoids: http://www.steelsoldiers.com/showthread.php?137569-M939A2-CTIS-PCU-solenoid-replacement&highlight=

You should also check the wire connections to the ECU and to the PCU.

 

[Coffey1]

Just don't remove wires or unplug Ctis box with power on.

 

[RedBlok]

Just don't remove wires or unplug Ctis box with power on.

Understood. I have been careful to remember that, but thanks for the reminder.

Thanks for the thread also

 

[Hawkdriver]

Great thread and I don't mean to hijack it but wanted to ask a question about a similar issue on my 1989 M923a2. I've been working to get my CTIS to work and have removed all the schrader valves from the wheel valves and replaced a bad valve on one wheel. Now when I get the pressure built up I can hear the system click and can hear some air exhaust out but haven't had a helper to push the button so I can locate exactly where the air is exhausting and then it goes to five blinking lights.

My question is since its trying to do its job does that mean it's not bad solenoids and must be a leak somewhere that's making go into fault mode?

 

[Coffey1]

Yours may be a bad transducer it thinks it has too much air and is dumping air .
That would be the pressure transducer on the pcu small black box.