W DOC AIRBUS | TSM A320F

APU Fault Relay failure (131-9(A))

TASK 49-00-81-810-863-A
APU Fault Relay failure (131-9(A))

1. Possible Causes
  • FAULT RELAY SHOWS CIRCUIT FAILURE
  • BOARD-ANN LT TEST & INTFC [7LP]
  • aircraft wiring
  • ELECTRONIC CONTROL BOX [59KD]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 33-14-00-710-001
Operational Test of the Lights
AMM 33-14-33-000-001
Removal of the Annunciator-Light Test and Interface-Board
AMM 33-14-33-400-001
Installation of the Annunciator-Light Test and Interface-Board
ASM 496101
AMM 49-61-34-000-003
Removal of the Electronic Control Box (ECB) (131-9(A))
AMM 49-61-34-400-003
Installation of the Electronic Control Box (ECB) (131-9(A))
3. Fault Confirmation
Subtask 49-00-81-710-076-A ** ON A/C NOT FOR ALL
A. Read-out of ECB Trouble-Shooting Data
   (1) Put the APU MASTER SW to the ON position.
   (2) Get access to the APU LAST LEG/PREVIOUS LEG report.
   (3) Push the '>'-key adjacent to the related CFDS failure message.
   (4) If the MCDU menu shows:
FAULT RELAY SHOWS CIRCUIT FAILURE

  • do the Fault Confirmation that follows:
     (a) Get access to the APU GND SCANNING menu.
4. Fault Isolation
Subtask 49-00-81-810-066-A ** ON A/C NOT FOR ALL
A. If the APU GND SCANNING menu gives the maintenance message:

WRG: APU FAULT RELAY

associated with Fault Code Number (FCN) 136

   (1) If the FAULT/ON annunciator lights on the APU MASTER SW P/BSW (14KD) do not come ON:
     (a) If the fault continues:
  • replace the APU MASTER SW (14KD).
   (2) If the FAULT/ON annunciator lights on the APU MASTER SW P/BSW (14KD) come ON:
  • do a check and repair of the aircraft wiring from the ECB (59KD) AB/H5 to
    the RELAY-ANNUNCIATOR-LIGHT TEST AND INTERFACE-BOARD (7LP) A/39
    and
    the RELAY 2-FIRE EMER STOP (6WF) A/X2 ASM 496101.
     (a) If the fault continues:
Subtask 49-00-81-710-077-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:34:37 UTC
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