APPARENT HYDRAULIC DIAGNOSTIC CENTER (HDC) SYSTEM PROBLEM - Continued
Check for open or short circuit in cable assemblies W2 and W3.
Disconnect W2 or W3 cable assembly electrical lead going into electrical connector of solenoid valve on
primary manifold, forward manifolds, or aft manifold identified in "CIRCUIT FAULT" message
(Figures 24 and 25).
Reference individual cable assembly wiring schematic diagrams (for cable assemblies W2 through W4)
in FP-23 through FP-28, and HDC control box connections pin number signal name (WP 0004) , and
trace signal path for the "CIRCUIT FAULT" solenoid valve energizing voltage (28 VDC) from a connector
on HDC control box (J2 or J3) to a connector on umbilical disconnect bracket (W2J1 or W3J1), through
umbilical cable connectors W4P5 or W4P6, respectively.
Figure 24. Umbilical Cable Assembly W4 Connection to Umbilical Cable Disconnect Bracket.
Disconnect umbilical cable connector W4P5 or W4P6 (as applicable) associated with "CIRCUIT FAULT"
solenoid valve from cable assembly W2J1 or cable assembly W3J1 (as applicable) connector on
umbilical disconnect bracket.
Perform continuity test and check for short circuit to cable ground (connector case/shell) for two pins/
wires in applicable embedded cable assembly (W2J1 or W3J1) that route 28 VDC energizing voltage
from HDC control box to solenoid valve associated with "CIRCUIT FAULT" message (28 VDC energizing
voltage is applied between pins 1 and 2 on three-pin solenoid valve electrical connector on all solenoid
Refer to FP-21 Solenoid Valve Electrical Wiring Diagram.