A bit late to conversation, however, is the tire losing pressure with the CTIS activated or while in storage? I have recently had issue with the CTIS wheel valve where it dumped the air from a rear while underway. I could not manually inflate the tire. Air would go back thru CTIS system and vent thru manifold. I would suggest two things as trouble shooting.
1. Remove the filter from the system at the 90 deg wheel fitting. Reduce (twice is easiest) with pipe fittings. Place your Valve stem from the Wheel Valve on the last reduction. Inflate and monitor. Obviously use teflon tape and ensure no leaks at fitting joints. If leaking, obviously not the CTIS but the Wheel and its fittings.
2. Reconnect the CTIS system from above test. Dissassemble the fitting on the Wheel Stud. With a sleeve and plug, dead head the system going back to the manifold.. Manually inflate to desired pressure. Monitor to determine if you lose pressure over time. Again checking the fittings. If no pressue lost over time, I would suspect the Wheel Valve. When the CTIS is not activated, the Wheel Valve should be closed and not allow air to leak back thru system.
Hope this helps...
