TM 9-2320-386-10 Change 1 2-63 2-19. OPERATION OF CENTRAL TIRE INFLATION SYSTEM (CTIS) (Contd) c. Run Flat Mode. CAUTION If tire condition deteriorates and cannot maintain at least fifty percent of its lowest set point, run flat mode should be aborted to prevent equipment damage. NOTE • By pressing a terrain switch on the control panel, a vehicle operator can start a pressure check cycle, beginning with the initial test pressure sequence. After the initial test pressure sequence has started, if air feeder lines and tires cannot hold at least 6 psi (41 kPa), the system will sense a failure and the control panel dis- play will read FLAT. With the presence of a flat tire indicated, the vehicle operator may elect to call for assistance, or he may try to drive to a repair center using the vehicle’s run flat mode. • Run flat mode supplies pressure to the air lines and to all wheel valves and allows maximum possible air pressure to the damaged tire. • RUN FLAT ACTIVE will be displayed on the LCD and the tire pressure will be indicated in flashing lower case PSI. (1) Run flat mode is engaged by pressing and holding for three seconds the terrain button that the tire failure occurred in. NOTE • PRESSURE ADJ. ABORT will be shown on the LCD, followed by the normal display for the selected terrain when the set point is reached. • By aborting any setting, the ECU will be in a stand by mode. Ensure the correct terrain button is pressed and the CTIS is allowed to complete a cycle to start the auto timer in the ECU. (2) Run flat mode can be aborted by pressing any terrain switch. CAUTION In the event of CTIS failure, pressure/speed limitations displayed on data plate must be observed when manually inflating/deflating tires. (3) In the event of system failure, tires may be inflated manually (para. 3-9). Table 2-3. Required CTIS Limits. SET TIRE ALLOWABLE DRIVING CONDITION POINTS PRESSURE RANGE SPEED RANGE Highway 45 psi 43-47 psi (296-324 kPa) 0-56 All Speeds Cross-Country 33 psi 31-35 psi (214-241 kPa) 0-36 mph Sand/Mud/Snow 20 psi 18-22 psi (124-152 kPa) 0-16 mph Emergency 13 psi 11-15 psi (76-103 kPa) 0-5 mph d. Operation in Extreme Cold. Turn OFF the CTIS during operation in extreme cold, -0° to -65°F (-18° to -54°C).