W DOC AIRBUS | TSM A320F

APU Oil-Heater (P28) Fault (131-9(A))

TASK 49-00-81-810-870-A
APU Oil-Heater (P28) Fault (131-9(A))

1. Possible Causes
  • OIL HEATER FAILURE
  • damage/contamination of electrical connector P28
  • APU OIL HEATER (P28)
  • APU AUX CTL RELAY (32KD)
  • aircraft wiring
  • SERVICE BUS 2 (214XP-B)
  • APU OIL HEATER (8093KM)
  • P/BSW-APU/MASTER SW [14KD]
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
TSM TASK 24-42-00-810-802-A
Loss of the 214XP Busbar in Ground Service Configuration
ASM 496104
AMM 49-96-00-040-001
Deactivation of the Oil Heater System (131-9(A))
AMM 49-96-00-440-001
Reactivation of the Oil Heater System (131-9(A))
AMM 49-96-51-000-002
Removal of the Oil Heater (131-9(A))
AMM 49-96-51-400-002
Installation of the Oil Heater (131-9(A))
AMM 49-96-51-960-001
Replacement the Oil Heater by the Cover Plate (131-9(A))
AMM 49-96-51-960-002
Replacement the Cover Plate by the Oil Heater (131-9(A))
3. Fault Confirmation
Subtask 49-00-81-710-090-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 '>' adjacent to the related CFDS failure message:
  • the MCDU menu shows:
    OIL HEATER FAILURE
   (4) Fault Confirmation
     (a) Not applicable. To confirm the fault, the APU must be cold soaked.
4. Fault Isolation
Subtask 49-00-81-810-073-A ** ON A/C NOT FOR ALL
A. If the APU LAST LEG/PREVIOUS LEG menu gives the maintenance message:

APU OIL HEATER P28

associated with Fault Code Number (FCN) 115

  • do a check for damage/contamination of electrical connector P28 of the APU OIL HEATER (P28).
   (1) If the electriacl connector P28 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 3 of the APU OIL HEATER (P28).
     (a) If the resistance value is not between 30 Ohms and 70 Ohms:
     (b) If the resistance value is between 30 Ohms and 70 Ohms:
  • replace the APU AUX CTL RELAY (32KD).
       1 If the fault continues:
  • do a check and repair of the aircraft wiring from
    the APU OIL HEATER (P28) P28/2 to the SERVICE BUS 2 (214XP-B)
    and
    the APU OIL HEATER (P28) P28/1 to GND
    ASM 496104.
         a If the fault continues:
Subtask 49-00-81-810-073-B ** ON A/C NOT FOR ALL
A. If the APU LAST LEG/PREVIOUS LEG menu gives the maintenance message:

APU OIL HEATER (8093KM)

associated with Fault Code Number (FCN) 115

   (1) If the oil heater is installed on the APU:
     (a) If the oil heater is considered necessary by the operator:
  • Make sure that the oil heater system is activated, if not do the activation procedure AMM 49-96-00-440-001.
  • If the fault continues:
    . Go to step (3).
     (b) If the oil heater is not considered necessary by the operator:
  • Make sure that the oil heater system is deactivated, if not do the deactivation procedure AMM 49-96-00-040-001.
NOTE: The oil heater can be replaced by the cover plate AMM 49-96-51-960-001.
   (2) If the oil heater is not installed on the APU:
     (a) If the oil heater is not considered necessary by the operator:
  • Make sure that the oil heater system is deactivated, if not do the deactivation procedure AMM 49-96-00-440-001.
     (b) If the oil heater is considered necessary by the operator:
  • If the fault continues:
    . Go to step (3).
   (3) If the fault continues:
  • do a check for damage/contamination of electrical connector P28 of the APU OIL HEATER (8093KM).
     (a) If the electrical connector P28 is damaged/contaminated:
  • do a repair/cleaning.
     (b) If the electrical connector is OK:
  • use a MULTIMETER - STANDARD to do a resistance check across pin 1 and pin 3 of the APU OIL HEATER (8093KM).
       1 If the resistance value is not between 30 Ohms and 70 Ohms:
       2 If the resistance value is between 30 Ohms and 70 Ohms:
  • replace the APU AUX CTL RELAY (32KD).
         a If the fault continues:
  • do a check and repair of the aircraft wiring from
    the APU OIL HEATER (8093KM) P28/2 to the SERVICE BUS 2 (214XP-B)
    and
    the APU OIL HEATER (8093KM) P28/1 to GND
    ASM 496104.
    . If the fault continues:
  • replace the P/BSW-APU/MASTER SW [14KD] .
. If the fault continues:
  • do a check and repair of the aircraft wiring from the APU AUX CTL RELAY (32KD) A/X2 to APU MASTER S/W (14KD) A/A1.
. If the fault continues:
[Rev.8 from Aug 2018] 2026.04.04 04:34:37 UTC
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