TM 10-3930-675-20-1 0040 00-2 BOOM LIFTING/LOWERING TROUBLESHOOTING - CONTINUED 0040 00 Table 1. Error Code 126 - Joystick-to-ECU (790) Failure Troubleshooting Procedures - Continued. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Error Code 126 - Joystick-to-ECU (790) Failure - Continued b. Check ECU (790) connector 1 and tray grounding leads for proper connections. a. Connect any loose or disconnected connections. Push  ECU  mounting  tray  in and install cover. b. Repair or replace any damaged connectors (WP 0111 00). Push ECU mounting tray in and install cover. c. Check     voltage     between connector  X155  pin  1  and pin 13. d. If voltage in step c was not the same as on the “DIAG SERVO    5    (13)”    menu, check   continuity   between ECU (790) connector 1 pin 9 and connector X155 pin 1 and   between   ECU   (790) connector   1   pin   26   and connector X155 pin 13. If    continuity   is    not    present, repair or replace connectors (WP 0111 00). e. Remove joystick cover and disconnect  connector  from joystick. f.  Check  continuity  between joystick   connector   pin   9 and connector X155 pin 12 and between connector X155 pin 12 and connector X155 pin 14. If    continuity   is    not    present, repair or replace connectors (WP 0111 00). g. Check  continuity  between connector X155 pin 14 and ECU (790) connector 1 pin 27   and   between   joystick connector pin 10 and connector X155 pin 13. If    continuity   is    not    present, repair or replace connectors (WP 0111 00). h. Check  continuity  between joystick   connector   pin   8 and connector X155 pin 1. If    continuity   is    not    present, repair or replace connectors (WP 0111 00).