M925A2 CTIS operation?

[barkster]

I'm looking at a couple m925a2 trucks and I was driving them and thr option selectors for ctis are all lit and when I push one of the buttons on the ctis it lights up a second then they all go back to lit up. How do u set the option u want. Do I have to hold down the button or something. They all do the same thing so I think I'm missing something.

 

[Andyrv6av8r]

If all of the lights are on the system isn't working. All lights on means a problem. Pushing a button won't fix it.

 

[barkster]

Thats kind of what I was thinking, well at least the tires stay inflated

 

[Alexsha]

5 lights flashing, 5 lights solid, or something else?

 

[Coffey1]

5 lights flashing good. Five solid bad.
If they are all solid red the ecu is shot.
All flashing there's another problem.
Hit run flat and if it's. A tire that's low it will bring it back up then hwy light will go solid and run flat light will go out.

 

[Alexsha]

5 flashing is an electrical issue or not enough pressure to operate. The ctis will not turn on at that point. I think 4 flashing is fixed by the run flat selection.

Do you hear clicking from the controller on the cab floor? If there's no sounds, it's probably electrical.

 

[barkster]

I didn't pay too much attention, I was just test driving to purchase and neither of us really knew how it was supposed to operate. I just pushed a couple of the buttons and then it would light up solid then they would all light up again but don't recall if they were blinking or solid. So how is it supposed to work when you select an option. I figured the option you selected would illuminate an the rest would go out?

 

[Alexsha]

More than 1 light at a time is generally bad. When the truck starts highway should flash. When the truck reaches 120psi, if all is well, you'll hear clicks and pops and the system will do a tire pressure check. If it's low it will keep flashing highway and fill. When complete highway will go solid. Basically, single flashing is pressure check and inflate/deflate. Single solid is at pressure for selected option.

 

[Coffey1]

Yes you are correct but if tire is below low set point 4 lights will flash and will not do anything else until you hit run flat then you will have a flashing hwy and run flat light unroll it gets to high setpoint then run flat will quit flashing and hwy will continue flashing until it reachs prober setpoint then will go to solid red light.

 

[barkster]

got my truck yesterday and this is what happened for other reference. When I looked at the truck all the lights on CTIS were blinking, when I pushed a button it would go solid for a second then all would start blinking. I waited till I got home then I pressed the run flat button as suggested, things started happening and the lights quite blinking. Then I let that go for a min then pressed sand, again it stayed solid and you could hear valves opening and closing then it started letting the air of tires, cool. Next I hit highway and it stayed lit more valves opening and closing. So I think what someone suggested was the key, press the run flat if all lights are blinking. Not sure if it resets something or what but that seemed to be what got mine working and I drove three of these and all CTIS on all of them were blinking and not functioning either so that must have to be pressed first?? Thanks, seems like everything on my truck works .....

 

[Alexsha]

It would be nice if 5 lights blinking didn't indicate either an electrical issue or pneumatic.

 

[barkster]

?? that's what worked for me, but I'm not sure I had 5 blinking it seemed like just the first 3 or 4?

 

[Alexsha]

?? that's what worked for me, but I'm not sure I had 5 blinking it seemed like just the first 3 or 4?

5 solid lights is a DEAD ECU. No coming back. Here's the rest according to the manual:

5 Lights Flashing

• System shuts off at least one channel due to fault detection on a CTIS component.
  • System closes wheel valves.
  • System may periodically cycle PCU to determine if fault still exists.
  • On 2-channel systems, operation may be allowed on the unaffected channel.
  • Get service at next opportunity.
  • No ability to override system.

​

4 Terrain Lights Flashing or CHECK TIRES Flashing

• Indicates low pressure in one or more tires. Stop vehicle and identify damage.
  • ​System shuts off, closing wheel valves, and waits for operator instruction.
    
  • Tire damage is possible.
    
  • CTIS should not be operated if major tire damage is found.
    
  • Repair tire before continuing to operate vehicle.
    
  • On 2-channel systems, normal operation will continue on the unaffected channel.
    
  • If tire damage is minimal, operate CTIS by selecting RUN FLAT.

Note: Repeated use of RUN FLAT to override mode light warnings may result in tires infl ating higher than set point.
​

Note: Excessive air seal leakage on cold weather startup may result in "4-5 Mode Lights" warning. If no tire damage exists, this condition will self-correct as seals warm up with use.
​

​2 Terrain Lights on Solid

• System has shut off, closing wheel valves, with tire pressure between two mode settings.
  • Inflating or defl ating tires is taking too long.
  • CTIS is still operational.
  • Select any mode button to re-attempt pressure change.
  • On 2-channel systems, normal operation continues on unaffected channel.
  • Frequent occurrences may indicate need for service.​
    

Single Terrain Light

• Flashing - System is working to achieve new pressures associated with that mode light.
• Solid - Pressure is achieved, system is not active, and wheel valves are closed.

So basically, 5 blinking lights you're hosed. You have something to fix and pressing a button will NOT fix the issue. Look for an electrical issue (solenoids in PCU) or a major air leak.
4 linking lights, check for tire damage. If good, run flat away.

 

[barkster]

awesome let me guess you pulled that out of manual somewhere. Mine was the 4 lights for sure... I haven't found operators manual helpful too much...

 

[Alexsha]

Might not have the right version. Using the guide I was able to easily diagnose 2 dead solenoids.

 

[hokie8358]

just found this question on forum and I was going to post the same questions in regards to CTIS operation on initial startup. my m925a2 has been sitting for about 3 weeks without cranking. I am in the idle of a cab resto. job with upgraded air ride seats and floor rhino liner. when mine is building air pres. hiway blinking. then at 120psi. the cab ctis valve in floor board behind winch controls starts clicking on and off. then run flat comes on with highway both blinking. then if I push run flat again it goes off and highway blinks a couple more seconds and the clicking in floor board again starts. then bam! the 4 top lights come on and primary and secondary tanks start building pressure to 120 again. yhen I clear them with push off highway button, then few clicks and we're back to highway and run flat. I also noticed 2 things before hand. front steer tires seemed lower than normal and passenger side rear 2 tires seemed as low as the front. sounds like me and you have same problem in regards to ctis issue.
first got the truck a year ago around now. Ctis worked flawless. then after sitting a few weeks(2-3) I noticed it started these light sequences on ctis system. with that being said, if you drive or crank every other day or 2 days! no issues! cycles normal! I live 2.5 miles off highway. usually by the time I drive it from my house to highway. the run flat and blinking lights go out and hi way blinks. and then after about 5-7 miles. high way stays lit and functions as norm.

 

[Coffey1]

OK once pressure gets to 120 then Ctis will to a tire check if any tires are just a little low it will fill them then go from a blinking hwy light to a solid light.

Now if one or more tires are way low it will not fill tires until you tell it to by pushing run flat then it will go from 4 blinking lights to blinking hwy and run flat then once all tires are at setpoint then run flat will turn off and go to a blinking hwy light and once the box checks everything again it will go to solid hwy light.

Continuously doing this can change set points
So bottom line is fix tire leaks. Or valve leaks

 

[hokie8358]

10-4! thanks for the quote! truck was overhaules and new tires back in 2011! so I say I need to check everything air leak wise! just shut truck off and heard windshield wiper leaking on pass. side! thanks

 

[hokie8358]

when I pulled the winch control panel and looked inside. I saw we're they wrote on it new in a sharpie. which, that could've been 2009 for all I know!