LMTV CTIS Question

[Suprman]

I have used ones

 

[cjacksoncpa]

Do they close at 95lbs? PM me the cost. I will be working on my truck next week and I will be retesting and might need it if it is still a problem.

 

[Suprman]

Somewhere around that pressure. You can use an ohm meter on yours see if its open with no air and closes at pressure. You can use a paperclip to jump the connector terminals and see if you ctis system comes on. my email is will atpawnking dotcom

 

[Unclebigbad]

Used a pressure switch that is adjustable, like the one used to control an onboard air compressor in our fire trucks, spliced the 2 wires from the organial switch to the new one. Takes a little pluming, but it's not hard. I would recommend installing a good gage in a t fitting in front of the new switch, so you can set the pressure required to close the circuit. Rember to wire the new switch so it opens for low pressure and closes for high pressure. Hopefully this works for you.

 

[Stellaevil]

The drawing is for an LMTV harness only but the Configuration wires will put the ECU into the wrong configuration. If you want to use this drawing the two config wires should go straight through with no splices. If you have a truck with a black CTIS ECU the communication wires are most likely hooked up to the vehicle diagnostic bus 9 way connector by the drivers leg. So the "Y" cable is not needed. Valves dumping air after reaching the Highway pressure....I found a PCU vent (in the cover) partially plugged, just remove the vent and re-check.

 

[Stellaevil]

I asked about the FMTV "Y" cable last week and received the attached wiring diagram. Can't answer whether the cable is the same for the M939A2 and FMTV.

Sorry, I didn't get this posted to the group earlier.
View attachment 676913

Tried to delete

 

[Stellaevil]

I asked about the FMTV "Y" cable last week and received the attached wiring diagram. Can't answer whether the cable is the same for the M939A2 and FMTV.

Sorry, I didn't get this posted to the group earlier.

View attachment 676913

The drawing is for an LMTV harness only but the Configuration wires will put the ECU into the wrong configuration. If you want to use this drawing the two config wires should go straight through with no splices. If you have a truck with a black CTIS ECU the communication wires are most likely hooked up to the vehicle diagnostic bus 9 way connector by the drivers leg. So the "Y" cable is not needed. Valves dumping air after reaching the Highway pressure....I found a PCU vent (in the cover) partially plugged, just remove the vent and re-check.

 

[firefinder]

As Stellaevil notes in the above posts, the attachment I provided may not be correct for your needs!

Please check with Stellaevil or your equipment manufacturer for your specific requirements.

My prior post has been updated with a WARNING notice.

 

[Stellaevil]

Here is an updated drawing for creating a CTIS "Y" harness to allow diagnostic communication with a replacement ECU on an older A0 vehicle.

 

[Stellaevil]

Here is an updated drawing for creating a CTIS "Y" harness to allow diagnostic communication with a replacement ECU on an older A0 vehicle. You probably do not need the CAN resistor or the wires if you just want to use the Dana software tool which will connect over the J1708

View attachment 680452

 

[Stellaevil]

Survey... Would anyone purchase replacement wheel valve lids that would allow the CTIS to function at -10 deg F. Essentially not having to manually vent the screws in the cold.

 

[snowtrac nome]

What do you mean, if my ctis doesn't work this winter I may have to look at something different, as our temp regularly dips to - 20.

 

[Stellaevil]

You just have to manually vent the wheel valve cover screws if the system won't close the valves at the highway tire pressure.

 

[snowtrac nome]

We will see I think its about every half hour It checks pressure.

 

[Stellaevil]

We will see I think its about every half hour It checks pressure.

The system will check the tire pressure every 15 minutes. But in the cold the wheel valves may have trouble closing after the check, then the system begins inflation cycling back up to the the highway target pressure denoted by the terrain light blinking continually. The vent screw in the WV covers is there to correct the extreme cold effect on the valve.

My question; is there a desire for continuously vented covers?

 

[Dduncan3b]

I'm having similar problems with CTIS. Tried 3 controllers with 2 that flash all 5 red and one nothing! Any help for a novice would be appreciated!

 

[Stellaevil]

I'm having similar problems with CTIS. Tried 3 controllers with 2 that flash all 5 red and one nothing! Any help for a novice would be appreciated!

Here is a link to the service manual; AXTS-0015
http://media.spicerparts.com/media

If the ECU comes up in 5 flashing lights at key-on the problem is electrical. A bad pressure reading from the PCU sensor or an open wire on the sensor or PCU coil.
Look at the sockets in the two connectors pull on the wires. If the system flashes Highway then faults out after a pressure check then the problem is a large air leak or open are line. Follow the service manual directions.

 

[Dduncan3b]

Thanks

 

[1951M1078]

Just started working on my CTIS. Not working. Some time I get the dash over speed light.?
But the best part is 5 lights "ON" !
Check the switch at the tank and it works. Adjusted the air up to 120 psi. Was at 90-100 +-.
Then drained the tanks.

Ran it for maybe 10 min's at 1500 rpm and saw the lights flicker then go out then Hwy.light only come on then nothing and back to 5 "ON" !

Check the dash harness all looks good.

I'm thinking it maybe best to go manual. PCU=$200-300 and the ECU is $300-500. But most parts are 15 + years old.

What do you guys think ?

Tires hold air ok, one seams to leak down more than others but their 2003's. Over a week will stay at 60 psi.

 

[Coffey1]

The biggest problem with these is the pcu.
Take the pcu apart clean it and check the solenoid coils if you have a blocked valve from dirt or a solenoid is not operating the system will never work.

CHECK THE PCU FIRST PERIOD !