W DOC AIRBUS | TSM A320F

APU AUTO SHUTDOWN - LOW OIL PRESSURE, Low Oil Level (131-9(A))

TASK 49-00-81-810-820-A
APU AUTO SHUTDOWN - LOW OIL PRESSURE, Low Oil Level (131-9(A))

1. Possible Causes
  • OIL LEVEL SHOWS LOW
  • oil level
  • damage/contamination of the electrical connector P8
  • LOW OIL LEVEL SWITCH (P8)
  • aircraft wiring
  • ELECTRONIC CONTROL BOX [59KD]
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
MULTIMETER - STANDARD
 B. Referenced Information
REFERENCE
DESIGNATION
AMM 49-00-00-860-008
APU Start by External Power
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 49-90-00-600-007
Check Oil Level and Replenish (131-9(A))
AMM 49-93-16-000-003
Removal of Oil Level Switch (131-9(A))
AMM 49-93-16-400-003
Installation of Oil Level Switch (131-9(A))
3. Fault Confirmation
Subtask 49-00-81-710-128-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 SHUTDOWN report.
   (3) Push the '>' adjacent to LRU DATA:
  • the MCDU menu shows
    OIL LEVEL SHOWS LOW

   (4) Start the APU and apply Bleed Air for 20 seconds, minimum AMM 49-00-00-860-008.
4. Fault Isolation
Subtask 49-00-81-810-096-A ** ON A/C NOT FOR ALL
A. If an APU auto shutdown occurs during the APU operation and the APU SHUTDOWN report gives the maintenance message:

LOW OIL PRESSURE
LOW OIL LEVEL

associated with the Fault Code Number (FCN) 99

  • do a check of the oil level in the APU oil reservoir AMM 49-90-00-600-007 and
    do a check for damage/contamination of the electrical connector P8 of the LOW OIL LEVEL switch (P8).
   (1) If the electrical connector of the LOW OIL LEVEL SW (P8) is damaged/contaminated:
  • do a repair/cleaning.
   (2) If the electrical connector is OK:
  • use a MULTIMETER - STANDARD to do a resistance check across pin 1 and pin 2 of the LOW OIL LEVEL SW (P8).
     (a) If the resistance value is < 100 kOhms:
     (b) If the resistance value is > 100 kOhms:
  • do a check of the aircraft wiring from
    the ECB (59KD) AB/H2 to the LOW OIL LEVEL SW (P8) P8/2
    and
    the LOW OIL LEVEL SW (P8) P8/1 to GND
    ASM 496104.
       1 If the fault continues:
Subtask 49-00-81-710-129-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:34:33 UTC
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