M923 CTIS problem

Suprman · Apr 3, 2013

I have a m923a2 the ctis was working. It started flashing all 5 lights. The left front tire is low. I hear some hissing from under the passenger dash area with the truck off I looked and couldnt find where though it is elusive. When I press the highway button you can hear a valve open and a little air flow. I pressurized the air system and did the tank drain procedure with the petcocks several times to make sure there wasnt any dirt or anything clogging up. Does anyone have any pointers for me?
Thanks,
Will

wreckerman893 · Apr 3, 2013

If you want your CTIS to work you have to have the TM. If you don't have the TM see if you can find it on digits. There is a sequence you have to go through to get it to work correctly (not that they ever work correctly). I have already disconnected two wheels on my M927 and will prob do them all as I change tires. The parts that go on the wheel are easy to booger up when you have to take them apart to change tires. A lot of units disconnected the systems due to mechanics that couldn't work on them or not being able to get parts. CTIS was one of those things that sounded good in theory, made a contractor a lot of money and were problematic. Good luck.

Suprman · Apr 3, 2013

I have the spicer troubleshooting guide I got that online I couldn't find a tm for the ctis. Maybe I am looking in the wrong place is it part of a whole vehicle tm? The spicer diag guide uses a cable and interface with pic software for diagnostics. How do you disconnect each wheel and disable the system? I have another truck that the system works on I can swap parts and see what happens.

Artisan · Apr 3, 2013

Suprman · Apr 3, 2013

Somewhere there is a diag port I ordered a code reader for it 140 bucks its supposed to be a standard cat communications port.

chadande · Apr 4, 2013

My CTIS generally works good. When it exibits the flashing lights (usually 4 I think) I do the following:

1. Start truck and let it build air pressure (CTIS lights will start flashing during this part).
2. Shut down truck.
3. Start truck again and immediately press one of the low pressure buttons (you should hear the large valve in the cab start working and air coming out of the valves on the axles).
4. When it has reached the lower pressure and the light is solid I air it back up to highway pressure.

So far this has always worked for me. I like the CTIS and have picked up enough spare parts to hopefully keep it working.

I'm intersted to hear how the tester / code reader works.

Suprman · Apr 4, 2013

Nope I tried that no luck I am faulting right from the get go. I cleaned out the inline collector going to the ctis box on the floor with the cover on it. It is very possible that there is some dirt or something somewhere in one of the wheel valves. I am tempted to air up the tires to like 60 psi and see if the system brings them down to 45 maybe the extra pressure will push out whatever is clogging up. The system did work fine a few days ago.

maccus · Apr 4, 2013

Suprfknman said:
Somewhere there is a diag port I ordered a code reader for it 140 bucks its supposed to be a standard cat communications port.

What reader did you order?

Suprman · Apr 4, 2013

It is on the most popular auction site launch cr-hd heavy truck code reader j1939 j1708. The spicer manual says codes can be read with a hand reader it references what each code means and has diagnostic flow charts. We shall see how it goes I should have it in a few days.

plowboy · Apr 5, 2013

The diagnostics are in the TM. The condensed version is the only big thing could be the controller,and if it is powering up and switching it is probably not the controller. Other the that it is all basic. Checking continuity in harness, voltage and resistance at various sensors, and look for leakage or blockage in the lines. I hear that there is a nifty diagnostic tool that will do it all for you....but my other experience suggests that the diagnostic tool is only useful AFTER you have enough understanding of how it works to be able to do it the old fashioned way.

Suprman · Apr 5, 2013

I am going to dig thru the tm's tomorrow and try to find the ctis diagnostic procedures. Do you know what tm and age they start on some of these tm's are like 800 pages.

Carlo · Apr 5, 2013

Suprfknman said:
I have a m923a2 the ctis was working. It started flashing all 5 lights. The left front tire is low. I hear some hissing from under the passenger dash area with the truck off I looked and couldnt find where though it is elusive. When I press the highway button you can hear a valve open and a little air flow. I pressurized the air system and did the tank drain procedure with the petcocks several times to make sure there wasnt any dirt or anything clogging up. Does anyone have any pointers for me?
Thanks,
Will

I had this problem on my 923A2 and its a valve blocked in that small canister you hear leaking. I hit my a little and it stopped. It might be from the cold and a little moister got inside.

Suprman · Apr 5, 2013

Are you talking about the box on the floor with the cover over it?
Will

TurboMustang370 · Apr 5, 2013

TM 9-2320-272-24-1 is where I start.

BKubu · Apr 5, 2013

You guys are giving me some hope on fixing my CTIS. I have owned several M939A2s and have never had one with perfectly working CTIS.

maccus · Apr 5, 2013

Having read the manuals which are good I sort of like this vendor manual also. I follows the manuals but is easier to read I think.

It also has a better diagnostic equipment section. Check out PDF page 14 for the start of the diagnostic section. Talked to my friend the CAT field service man and he said he has most/if not all of the connection equipment on his service truck. Need to download the program for my net book. Now to see if it will work on the M939A2.

Remember the RP1210A box needs a matching program card installed in it as it will not work by itself without it. (The box is used as
an interface for many other things other than CTIS systems.)

http://www2.dana.com/pdf/AXTS-0015.pdf

Suprman · Apr 5, 2013

I have the tm's and they reference diagrams but I cant find the diagrams

TNJMurray · Apr 5, 2013

Out of the 100 plus ctis we have purchase I think that 5 have worked , what a piece of you know what !! I have some of the parts In stock if you can trouble shot it and find out what you need. Good luck. Tnjmurray.com. Murco@tnjmurray.com

Suprman · Apr 6, 2013

In the spicer manual it shows a diagnostic port connector. On the passenger side by the door right under the dash are 2 ports one is the large military style vehicle diag port I dont know what the other is but it appears to be to small and not enough pins to be the ctis port. Does anyone know where the ctis diag port is?
Will

1 Patriot-of-many · Apr 6, 2013

Guess I'm lucky then Murco, Mine works fine with 30K miles on the truck. Great I just jinxed myself.

M923 CTIS problem

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