TM 9-2320-360-20-1 WARNING · Exercise extreme caution when working around wheels or under truck while engine Is running. Movement of truck may cause severe Injury or death. · Wear safety goggles when performing leakage tests on valves air hoses.  Failure to comply may cause serious eye Injury due to high air pressure. NOTE · Tire must be deflated to 60 psi (414 kPa) or less to perform this test · Pressure relief valve remains closed unless pressure to tires exceeds 85 psi (586 kPa) (1) Start engine (TM 9-2320-360-10). (2) Set CTIS controller selector to HIGHWAY position (TM 9-2320-360-10). (3) Move CTIS switch to ON position and/or push start button (TM 9-2320-360-10). (4) Check pressure relief valve for air leaks. (5) Shut off engine (TM 9-2320-360-10). NOTE Tire must be deflated to 60 psi (414 kPa)  or less to perform this test (1) Start engine (TM 9-2320-360-10). (2) Set CTIS controller selector to HIGHWAY position (TM 9-2320-360-10). (3) Move CTIS switch to ON position and/or push start button (TM 9-2320-360-10). (4) Check inside wheel seals for air leaks. (5) Shut off engine (TM 9-2320-360-10). NOTE Tire must be deflated to 60 psi (414 kPa)  or less to perform this test (1) Start engine (TM 9-2320-360-10). (2) Set CTIS controller selector to HIGHWAY position (TM 9-2320-360-10). (3) Move CTIS switch to ON position and/or push start button (TM 9-2320-360-10). (4) Check axle breathers for escaping car (5) Shut off engine (TM 9-2320-360-10). Change 1  2-849