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

[aztec]

Got it no more blinking lights it was the connections from the stis valve an the rear wheels where the ctis valve connects to the hub under the sheild on the wheel its a tube connection about 3/4 in dia with large tightning nut yea ha done

 

[RobertoGatos]

Got it no more blinking lights it was the connections from the stis valve an the rear wheels where the ctis valve connects to the hub under the sheild on the wheel its a tube connection about 3/4 in dia with large tightning nut yea ha done

Thats been the most common problem with our trucks. Even when they're really clean they still come loose with time.

Tested for leaks just like Suprman said. Eliminated all of those. Think the last thing left to go wrong is the wiring?

 

[Suprman]

Check the connection where the harness meets the plug for the pressure sensor. On the top of the valve body. Thats a problem are also. It gets alot of flex there.

 

[Alexsha]

I've been working on mine today. I get no air noise in the cab at all from the pneumatic controller. Once the system is up to pressure, it goes to 5 blinking lights without even doing anything. I fear my pneumatic controller is caput. Is there a way to test one? I don't have a spare to try and swap in.

 

[Suprman]

Did you check the air supply to the valve body? It needs air coming in to send air out for the pressure check.

 

[Alexsha]

Did you check the air supply to the valve body? It needs air coming in to send air out for the pressure check.

There is air, yes. Not sure on the pressure. What psi should be going into the body?

 

[Suprman]

Full pressure. System needs 120 psi to start and will cut out if air goes down past a certain point. The copper coiled line on the firewall by the governor is the valve body air feed there is the little catch trap inline though. The valve body consists of 3 solenoid valves and one pressure sensor. It will usually do something. Yours may be doing a quiet pressure check. Hard to hear over the engine. Can't hurt to pressurize the valve body output line and look for leaks.

 

[1 Patriot-of-many]

I've been working on mine today. I get no air noise in the cab at all from the pneumatic controller. Once the system is up to pressure, it goes to 5 blinking lights without even doing anything. I fear my pneumatic controller is caput. Is there a way to test one? I don't have a spare to try and swap in.

Yes, download the Spicer/dana troubleshooting PDF. You can check for continuity ect.

 

[Alexsha]

Full pressure. System needs 120 psi to start and will cut out if air goes down past a certain point. The copper coiled line on the firewall by the governor is the valve body air feed there is the little catch trap inline though. The valve body consists of 3 solenoid valves and one pressure sensor. It will usually do something. Yours may be doing a quiet pressure check. Hard to hear over the engine. Can't hurt to pressurize the valve body output line and look for leaks.

When I put pressure in the output line the front axle valve just blows air out the duckbill. That defiantly doesn't happen with everything hooked up normally. I'm going to try putting a gauge on the input line to see what pressure is reaching it.

 

[Suprman]

If you have a leak somewhere and only 15psi or so is reaching the quick release valves then they will dump.

 

[Alexsha]

Well, I tested the air line to the PCU and got 120+ psi. I ran it with the output line, pressure relief, and PCU pressure sensor all disconnected, but not one bit of air come out. As soon as the dash gauges read 120+ psi, 5 lights came on. Definitely seems electrical.

 

[MtnSnow]

Alexsha, Have you double checked that you do NOT have a valve core in the end of the turret valve that the CTIS is connected to? Finding a valve core in a valve stem of a tire will cause the 5 flashing lights as the system is unable to sense pressure for that wheel....

 

[1 Patriot-of-many]

Alexsha, Have you double checked that you do NOT have a valve core in the end of the turret valve that the CTIS is connected to? Finding a valve core in a valve stem of a tire will cause the 5 flashing lights as the system is unable to sense pressure for that wheel....

Good call, I forgot about that. I had one in one of my tractor wheels, it did that. Just go around with an inflater, try inflating at the wheel valve of each tire. If one of them won't take air, unscrew the fitting going into the turret. There will be a schrader valve in there, remove it.

 

[Alexsha]

I have not checked the wheels yet, but if I recall I've aired them from the wheel valves before. I'll have to double check.

Im fairly certain thar isnt the issue though. The system never sends any air out from the PCU. With the outlet line disconnected, no air is released. I disconnected the outlet, relief, and sensor. Nothing comes out. I'm guessing I have to apply voltage to the solenoids and test those.

 

[MtnSnow]

Air will not be released from the wheels unless there is approximately 15psi being supplied to the valves (air pressure Opens the valves)

Do you have the Spicer CTIS troubleshooting guide?

 

[Alexsha]

I've read through the guide. I just don't have a code reader so I don't know the error code. If the outlet from the PCU is disconnected there should be some air coming out the PCU before it goes to 5 lights, shouldn't it?

 

[Suprman]

It should do an initial pressure check as soon as the switch on the air tank tells the system that you are up to 120psi. It will send some air out from the valve body. This may be had to hear with the truck running though.

 

[Alexsha]

Finger over the outlet builds up no pressure. I also stuffed some paper towel into the outlet. It doesn't get blown out. Even 5 psi would have popped it out. No air is leaving the PCU at all. The TM troubleshooting says to replace the PCU.

Wet tank pressure switch is good.
120psi reaching PCU.
No air whatsoever leaving PCU.

I think the solenoids in the PCU are the next thing to check. If so, can I do a continuity/ohm check or do I need to apply 24v to each manually?

 

[Suprman]

If you have verified air coming into the valve body. You can open it and try to individually test the solenoids. I could see some moisture getting into the unit and sitting for a period of time and being stuck. The whole assembly can be carefully taken apart. When you remove the 3 valves themselves, use a small plastic or wood piece not metal to pry them out so you don't mar anything up.

 

[1 Patriot-of-many]

Sounds to me like you have a bad solenoid in the PCU. Follow the spicer guide and check them for continuity. Then take it apart like Suprman said.