Fault Message:

LH DEFUEL SOV/WRG

Fault Code:

284463BPK

Associated CAS:

L RD VALVE OPEN
(Advisory)

L DEFUEL VALVE/WRG FAULT shows when the conditions that follow occur:

• The Left Defuel Shut-off Valve is commanded to close
• The open feedback-signal for the Left Defuel SOV is true or the close feedback-signal is false
• The Electrical Management System (EMS)/Auxiliary Power Unit (APU) Start Contactor Assembly (ASCA) does not have a failure

OR,

• The Left Defuel SOV is commanded to open
• The open feedback-signal for the Left Defuel SOV is false or the close feedback signal is true
• The EMS/ASCA does not have a failure

• Fuel Management and Quantity Gauging Computer (FMQGC) (A47)
• Left Defuel Shut-off Valve (L3)
• Auxiliary Power Unit (APU) Start Contactor Assembly (ASCA) (A48)
• Junction Box (JB6)
• Junction Box (JB6)/PCB1
• Auxiliary Power Unit (APU) Main Battery
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. The External (RDCP) LCD shows the Left refuel shutoff valve failed after doing the STOP/SOV test on the RDCP and access CAIMS:

   • Select System Diagnostics
   • Select 28-00 FUEL
   • Select Computer (FMQGC CH A)(B)
   • Select LRU TEST
   • Select RDCP and Refuel Valves Data
   • Review the RDCP panel status and the Refuel Solenoid Status

2. Use the external RDCP and perform the SOV test for the LH defuel valve.
3. Does the LH valve status change from CLOSED to OPEN or OPEN TO CLOSED on the PMAT.

   1. If the valve status changes, go to step 7.
   2. If the valve status stays OPEN, continue with the next step.

4. Gain access to the Defuel shutoff valve (L2 and L3). Swap LH SOV (L3) with RH SOV (L2). Perform the SOV test from the RDCP.

   1. If the fault transfers to the opposite side, replace the LH SOV (L3) and do close out.
   2. If the fault does not transfer, continue with the next step.

5. Swap the valves back to original positions. Remove connector L3P1 and perform a wiring check as follows:
   NOTE: Turn ON aircraft power for wiring checks.

   From	To	Expected Result	Result
   L3P1-D	Airframe Ground	28 VDC
   L3P1-E	Airframe Ground	Continuity
   L3P1-C	Airframe Ground	Continuity

   1. If the wiring at L3P1-C does not have a ground, repair or replace wiring to GS52 or GS52 and do close out.
   2. If the wiring at L3P1-E does not have a ground, repair or replace wiring to GS53 or GS53 and do close out.
   3. If wiring checks are good, go to step 7.
   4. If the wiring at L3P1-D does not have 28 VDC, continue with next step.

6. Gain access to Junction Box 6. Open up the access cover to find test points. Perform a wiring check as follows:
   NOTE: The STOP/SOV switch would need to be depressed for wiring check.

   From	To	Expected Result	Result
   PCB1-TP60 for A/C 9002-9119 PCB1-TP57 for A/C 9120-9158	Airframe Ground	28 VDC
   PCB1-TP23	Airframe Ground	Continuity

   1. If the wiring check is good, go to step 8.
   2. If the 28 VDC is missing on TP60 or TP57 and TP23 has a ground, suspect JB6 relay K2 in PCB1.
   3. If 28 VDC is missing on TP60 or TP57, suspect JB6.
   4. If the ground is missing on TP23, continue with the next step.

7. Remove FMQGC from the tray. Perform a wiring check as follows:

   From	To	Expected Result	Result
   A47CP1-C5	JB6EP1-27	Continuity

   1. If the wiring check is not good, repair or replace wiring from FMQGC to JB6 and do close out.
   2. If the wiring check is good, continue with the next step.

8. Re-install or re-rack the FMQGC making sure it is fully and properly pushed into place.
9. Perform the SOV test on the RDCP, does the LH SOV fail.

   1. If YES, continue with the next step.
   2. If NO, do close out.

10. Replace the FMQGC.
11. Do close out.