1-23. AIR SYSTEM (CONT)
Figure 1-28. Air System (Cont)
(3) Air pressure in the tires is controlled by the CTIS ECU (6). The CTIS ECU provides
for five tire pressure settings which are; highway, cross-country, sand, emergency, and
run-flat. Kneeling valves (7) on the front tires allow the front of the vehicle to be lowered
for internal air transport (C-130 and C-141). Air pressure is also used to keep the cab
level through the use of air springs (8), mounted below the rear cab support, and a cab
leveling valve (9).