W DOC AIRBUS | TSM A320F

Data Memory Module P20 Fault (131-9(A))

TASK 49-70-00-810-821-A
Data Memory Module P20 Fault (131-9(A))

1. Possible Causes
  • DATA MEMORY MODULE SHOWS WRAP TEST FAILURE
  • DATA MEMORY MODULE SHOWS READ FAILURE
  • DATA MEMORY MODULE SHOWS CHECKWORD FAILURE
  • DATA MEMORY MODULE SHOWS APU S/N FAILURE
  • DATA MEMORY MODULE SHOWS WRITE FAILURE
  • damage/contamination of the electrical connector P20
  • aircraft wiring
  • DATA MEMORY MODULE (DMM) (P20)
  • ELECTRONIC CONTROL BOX [59KD]
  • DATA MEMORY MODULE (DMM) (8062KM)
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
JUMPER-WIRE
 B. Referenced Information
REFERENCE
DESIGNATION
AMM 49-00-00-860-008
APU Start by External Power
AMM 49-00-00-860-009
APU Shutdown by External Power (131-9(A))
ASM 496104
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))
AMM 49-73-32-000-001
Removal of the Data Memory Module (131-9(A))
AMM 49-73-32-400-001
Installation of the Data Memory Module (131-9(A))
AMM 49-73-32-600-002
Re-start of the DMM (131-9(A))
3. Fault Confirmation
Subtask 49-70-00-710-086-A ** ON A/C NOT FOR ALL
A. Read-out of ECB Trouble-Shooting Data
   (1) Get access to the APU LAST LEG/PREVIOUS LEG report.
   (2) Push the '>'-key adjacent to the related CFDS failure message.
   (3) If the MCDU menu shows:
DATA MEMORY MODULE SHOWS WRAP TEST FAILURE

  • Do the Fault Confirmation that follows:
     (a) Set the APU MASTER SW to the OFF position and wait 35 seconds, minimum.
     (b) Set the APU MASTER SW to the ON position.
     (c) Get access to the APU LAST LEG/PREVIOUS LEG report.
     (d) Push the '>'-key adjacent to TEST on the MCDU.
   (4) If the MCDU menu shows:
DATA MEMORY MODULE SHOWS READ FAILURE

DATA MEMORY MODULE SHOWS CHECKWORD FAILURE

DATA MEMORY MODULE SHOWS APU S/N FAILURE

  • Do the Fault Confirmation that follows:
     (a) Set the APU MASTER SW to the OFF position and wait 35 seconds, minimum.
     (b) Set the APU MASTER SW to the ON position.
     (c) Get access to the APU GND SCANNING menu.
   (5) If the MCDU menu shows:
DATA MEMORY MODULE SHOWS WRITE FAILURE

  • Do the Fault Confirmation that follows:
     (a) Start the APU AMM 49-00-00-860-008.
     (b) Get access to the APU GND SCANNING menu.
     (c) Shut down the APU AMM 49-00-00-860-009.
     (d) Wait until the ECB (59KD) power-down, speed < 7% plus 30 seconds.
     (e) Set the APU MASTER SW to the ON position.
     (f) Get access to the APU GND SCANNING menu.
4. Fault Isolation
Subtask 49-70-00-810-072-A ** ON A/C NOT FOR ALL
A. If the APU GND SCANNING menu gives the maintenance message:

DATA MEMORY MODULE P20

related to Fault Code Number (FCN) 241 or 244

  • Do a check for damage/contamination of the electrical connector P20 of the DATA MEMORY MODULE (DMM).
   (1) If the electrical connector P20 of the DMM is damaged/contaminated:
  • Do a repair/cleaning.
   (2) If the electrical connector P20 of the DMM is OK:
     (a) Disconnect the electrical connector P20 from the DMM/APU interface.
     (b) Do a check and repair of the aircraft wiring from
the ECB (59KD) AB/F11,F7 to structural ground, required value > 100 kOhms
and
the ECB (59KD) AB/F11 to AB/F7, required value > 100 kOhms,
ASM 496104.
     (c) Put a JUMPER-WIRE across the sockets 8 and 9 of the electrical connector P20 of the DMM on the APU harness side.
     (d) Do a check and repair of the aircraft wiring from
the ECB (59KD) AB/F11 to AB F7, required value < 10 Ohms
and
the ECB (59KD) AB/J2,J3 to structural ground, required value > 100 kOhms
and
the ECB (59KD) AB/J2 to AB/J3, required value > 100 kOhms,
ASM 496104.
     (e) Put a jumper across the sockets 10 and 11 of the electrical connector P20 of the DMM on the APU harness side.
     (f) Do a check and repair of the aircraft wiring from
the ECB (59KD) AB/J2 to AB/J3, required value < 10 Ohms
and
the ECB (59KD) AB/C6 to structural ground, required value > 100 kOhms
and
the ECB (59KD) AB/C6 to AB/F11, required value > 100 kOhms,
ASM 496104.
     (g) Put a jumper across the sockets 6 and 7 of the electrical connector P20 of the DMM on the APU harness side.
     (h) Do a check and repair of the aircraft wiring from the ECB (59KD) AB/C6 to AB/F11, required value < 10 Ohms, ASM 496104.
   (3) If the fault continues:
   (4) If the fault continues:
Subtask 49-70-00-810-073-A ** ON A/C NOT FOR ALL
B. If the APU GND SCANNING menu gives the maintenance message:

DATA MEMORY MODULE P20

related to Fault Code Number (FCN) 242 or 243

  • Do a check for damage/contamination of the electrical connector P20 of the DATA MEMORY MODULE (DMM).
   (1) If the electrical connector P20 of the DMM is damaged/contaminated:
  • Do a repair/cleaning.
   (2) If the electrical connector P20 of the DMM is OK:
   (3) If the fault continues:
Subtask 49-70-00-810-072-B ** ON A/C NOT FOR ALL
C. If the APU GND SCANNING menu gives the maintenance message:

DATA MEMORY MODULE (8062KM)

related to Fault Code Number (FCN) 241 or 244

  • Do a check for damage/contamination of the electrical connector P20 of the DATA MEMORY MODULE (DMM).
   (1) If the electrical connector P20 of the DMM is damaged/contaminated:
  • Do a repair/cleaning.
   (2) If the electrical connector P20 of the DMM is OK:
     (a) Disconnect the electrical connector P20 from the DMM/APU interface.
     (b) Do a check and repair of the aircraft wiring from
the ECB (59KD) AB/F11,F7 to structural ground, required value > 100 kOhms
and
the ECB (59KD) AB/F11 to AB/F7, required value > 100 kOhms,
ASM 496104.
     (c) Put a JUMPER-WIRE across the sockets 8 and 9 of the electrical connector P20 of the DMM on the APU harness side.
     (d) Do a check and repair of the aircraft wiring from
the ECB (59KD) AB/F11 to AB F7, required value < 10 Ohms
and
the ECB (59KD) AB/J2,J3 to structural ground, required value > 100 kOhms
and
the ECB (59KD) AB/J2 to AB/J3, required value > 100 kOhms,
ASM 496104.
     (e) put a jumper across the sockets 10 and 11 of the electrical connector P20 of the DMM on the APU harness side.
     (f) Do a check and repair of the aircraft wiring from
the ECB (59KD) AB/J2 to AB/J3, required value < 10 Ohms
and
the ECB (59KD) AB/C6 to structural ground, required value > 100 kOhms
and
the ECB (59KD) AB/C6 to AB/F11, required value > 100 kOhms,
ASM 496104.
     (g) Put a jumper across the sockets 6 and 7 of the electrical connector P20 of the DMM on the APU harness side.
     (h) Do a check and repair of the aircraft wiring from the ECB (59KD) AB/C6 to AB/F11, required value < 10 Ohms, ASM 496104.
   (3) If the fault continues:
   (4) If the fault continues:
   (5) If the fault continues:
Subtask 49-70-00-810-073-B ** ON A/C NOT FOR ALL
D. If the APU GND SCANNING menu gives the maintenance message:

DATA MEMORY MODULE (8062KM)

associated with Fault Code Number (FCN) 242 or 243

  • Do a check for damage/contamination of the electrical connector P20 of the DATA MEMORY MODULE (DMM).
   (1) If the electrical connector P20 of the DMM is damaged/contaminated:
  • Do a repair/cleaning.
   (2) If the electrical connector P20 of the DMM is OK:
   (3) If the fault continues:
   (4) If the fault continues:
Subtask 49-70-00-710-087-A ** ON A/C NOT FOR ALL
E. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:34:42 UTC
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