TM 10-3930-675-20-1 0040 00-8 BOOM LIFTING/LOWERING TROUBLESHOOTING - CONTINUED 0040 00 Table 5. Error Code 154 - Lift Cylinder Boom Up Valve, Wiring Circuit Failure Troubleshooting Procedures. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Error Code 154 - Lift Cylinder Boom Up Valve, Wiring Circuit Failure 1.  Remove   ECU   (790)   cover from operator’s seat base and slide ECU mounting tray out (WP 0079 00). 2.  Check ECU (790) connector 2 and tray grounding leads for proper connection. 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. 3.  Check voltage between connector X158 pin 1 and pin 2.  If  voltage  is  not  present, check    continuity    between: ECU (790) connector 2 pin 11 and  connector  X158  pin  2; between ECU (790) connector    2    pin    10    and connector  X159  pin  1;  and between connector X159 pin 1 and connector X158 pin 1. If   continuity   is   not   present, repair or replace connectors (WP 0111 00). 4.  Perform    voltage    check    at connector X154 pin 3. a.  If 20-25V is present, check continuity    between    con- nector X154 pin 3 and ECU (790) connector 2 pin 9. If   continuity   is   not   present, repair or replace connectors (WP 0111 00). b. If  voltage  is  not  present, check   continuity   between connector  X154  pin  3  and emergency stop switch (250) pin 2. If   continuity   is   not   present, repair or replace connectors (WP 0111 00). 5.  Move     operator’s     cab     to transport position and remove transmission   access   covers (WP 0135 00). DIAG SERVO 9(13)         OUTPUT/INPUT LIFT       0mA    0mA LOWER      0mA    0mA