Disable the CTIS?

[KEN2]

HELP PLEASE? My LMTV had sort of new front right go flat Sunday killed tire. Called service truck they changed tire. 3 miles later spare went from 70lbs to 20. Any thoughts how i can get truck home?

CTIS blinking all lights after flat.

 

[simp5782]

HELP PLEASE? My LMTV had sort of new front right go flat Sunday killed tire. Called service truck they changed tire. 3 miles later spare went from 70lbs to 20. Any thoughts how i can get truck home?

CTIS blinking all lights after flat.

Air the tire back up using your air chuck and glad hand. And unplug the CTIS before you start the truck. If the tire has a hole in it causing the air loss address it as well

 

[Suprman]

Take the banjo bolt out see if your spare had a regular bolt not a banjo bolt. You can remove the ctis hose off the valve stem and screw in a standard schrader valve. Then just fill the tire with air. Be careful when screwing in the schrader valve you dont want to over tighten it in. You can take the schrader valve out of the air fill on the ctis valve.
Will

 

[KEN2]

banjo bolt, i assume the bolt that attaches the ctis to lug? The Service guy used the the bolt from the tire that went flat. There was not a bolt in the spare. my ctis thing has manual inflate valve on it. but soons as I put air in it leaks out when i drive a mile or two. but the tire it self or the ctis things on tire are not leaking. 70lbs to 20 in 5 min driving.

Thanks for any help.

 

[simp5782]

banjo bolt, i assume the bolt that attaches the ctis to lug? The Service guy used the the bolt from the tire that went flat. There was not a bolt in the spare. my ctis thing has manual inflate valve on it. but soons as I put air in it leaks out when i drive a mile or two. but the tire it self or the ctis things on tire are not leaking. 70lbs to 20 in 5 min driving.

Thanks for any help.

Then unplug the CTIS box in the cab and then remove the CTIS fitting on the wheel where it meets the valve stem and air it up. Delete the CTIS and see if it still holds air. if not then you have a hole in it somewhere or a bad O -ring.

 

[Suprman]

Ok was the system working fine before? If you havent 100 percent visually verified it already pull the bolt out and verify that its a banjo bolt and not a regular bolt.

 

[KEN2]

system worked fine.... 95% of time. some times it would go little crazy with lights but after restart of truck all was fine. It has lowered and increased air when off road several times. also I have never added air to tires. if sitting long time and little low it pumps them up.

yes banjo bolt in hole I was thought bolt was interesting how it worked when he put back together a bolt with a hole in it.

 

[Suprman]

For some reason that tire is seeing low pressure when the system goes to do a pressure test and its allowing the wheel valve to open and drop pressure. Take the banjo/hose off, put a plastic bag scrunched down over the banjo/hose and rubber band over the hose tight. Give it an hour if bag expands then air is leaking out thru the valve.

 

[KEN2]

so possible the wheel that was on truck went bad and also the spare wheel doing same thing?

 

[Suprman]

If something is blocking the hub port, where the banjo goes then the tires can mysteriously loose air. A main culprit is a regular bolt in place of the banjo. If the wheel valve is bad and air is leaking back thru that will cause a pressure drop but a working system will usually keep the tire inflated until you park the truck for a day or two and it leaks down. If the system thinks its sending high pressure to the wheels, but for some reason there is a leak or blockage and only low pressure makes it to the wheel valve then it can dump air instead of fill.

 

[KEN2]

ok thanks I am starting to under stand this thing a little better. so some where something is causing low pressure... for this front right and dumping my air.

One guy I spoke to who has LMTV said he had issue with ctis hub seal. but was not emptying tire this quick.

 

[Suprman]

If the hub seal was bad, leaking air pressure can cause the wheel valve to see low pressure and dump air. Wheel valves are mechanical. I think its around 20psi holds open the wheel valve and dump down to around 20psi. So if the system is sending say 65psi to fill but only around 20psi makes it to the wheel valve due to a leak then the tire goes flat. With the tires aired up and the controller unplugged if you tires still go flat then its a wheel or wheel valve issue.

 

[Ohiobenz]

Air the tire back up using your air chuck and glad hand. And unplug the CTIS before you start the truck. If the tire has a hole in it causing the air loss address it as well

If the hub seal was bad, leaking air pressure can cause the wheel valve to see low pressure and dump air. Wheel valves are mechanical. I think its around 20psi holds open the wheel valve and dump down to around 20psi. So if the system is sending say 65psi to fill but only around 20psi makes it to the wheel valve due to a leak then the tire goes flat. With the tires aired up and the controller unplugged if you tires still go flat then its a wheel or wheel valve issue.

In this scenario would the CTIS not continue to try to fill up to pressure?
I have a similar situation, left rear has 0 psi but CTIS doesnt kivk on to fill it.