Have the vehicle operator move the APRON control lever to LOWER until transducer T1 reads less than
500 psi (3447.379 kPa).
Have the vehicle operator move the APRON control lever to RAISE until transducer T1 reads greater
than 3000 psi (20684.27 kPa). (This indicates that V17 has directed flow from the apron circuit to
Valve V1 check:
Turn off the HDC Control Box by depressing the POWER button.
Have the vehicle operator stop the engine.
Manually open valve V23 by moving the handle to a fully vertical position.
Have the vehicle operator start the engine.
Power up the HDC Control Box by pressing the POWER button.
Use the LINE UP and LINE DOWN buttons to select valve V1. Press CHANGE POSITION button to
close valve V1.
Have vehicle operator move the EJECTOR CONTROL lever forward and backward. Ensure that the
ejector does not move. (This indicates that valve V1 has closed.)
Push the RESET VALVE button on the HDC Control Box and verify all the valves are set to the power
OFF setting and are in the default position as shown in Table 1.
When the Functional Check-Out is complete, proceed to use the HDC system as an aid to troubleshoot a
problem with the vehicle hydraulic system or shut down the vehicle per TM 5-2350-262-10 and stow the HDC
Control Box and umbilical cable W4.
Table 2. HDC System Solenoid Valve Definition.
Primary Manifold Ejector Control
No. 1 Actuator,
No 1. Actuator,
No. 4 Actuator,
Primary Manifold Right Hand