TM 10-3930-675-20-1 0040 00-13 BOOM LIFTING/LOWERING TROUBLESHOOTING - CONTINUED 0040 00 Table 8. Error Code 158 - Lift Cylinder Boom Down Valve, Component Failure Troubleshooting Procedures. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Error  Code  158  -  Lift  Cylinder  Boom  Down Valve, Component 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.  Move operator’s cab to transport position and remove transmission rear access cover (WP 0135 00). 4.  Disconnect    electrical    con- nector    from    boom    down solenoid 6004. Error code 157 will    now    show.    Perform voltage    check    at    solenoid 6004 connector. If 20-25V is present at solenoid 6004  connector,  replace  boom down solenoid (WP 0169 00). 5.  Ensure that ignition switch is in  OFF  position.  Disconnect connector X158 located under driver’s seat. 6.  Check    continuity    between connector 6004 pin 1 and pin 2    and    between    connector 6004  pin  1  and  chassis  and connector   6005   pin   2   and chassis. a. If continuity is present, repair or   replace   connectors   (WP 0111 00). b. If   wiring   harness   must   be replaced, notify SRA. 7.  Check    continuity    between connector   X158   pin   4   and ECU (790) connector 2 pin 4 and    between    ECU    (790) connector    2    pin    10    and connector X159 pin 1. If    continuity   is    not    present, repair or replace connectors (WP 0111 00). DIAG SERVO 9(13)         OUTPUT/INPUT LIFT       0mA    0mA LOWER      0mA    0mA