W DOC AIRBUS | TSM A320F

APU AUTO SHUTDOWN - NO ACCELERATION, Oil Heater Fault (131-9(A))

TASK 49-00-81-810-833-A
APU AUTO SHUTDOWN - NO ACCELERATION, Oil Heater Fault (131-9(A))

1. Possible Causes
  • OIL HEATER FAILURE
  • 115 VAC at the APU OIL HEATER (P28)
  • OIL HEATER (P28)
  • wiring
  • APU MAIN RELAY (32KD)
  • ELECTRONIC CONTROL BOX [59KD]
  • 115 VAC at the APU OIL HEATER (8093KM)
  • OIL HEATER (8093KM)
  • APU AUX CTL RELAY (32KD)
  • aircraft wiring
  • SERVICE BUS 2 (214XP-B)
  • P/BSW-APU/MASTER SW [14KD]
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
1
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 49-61-34-000-003
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 49-96-00-440-001
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))
3. Fault Confirmation
Subtask 49-00-81-710-154-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 HEATER FAILURE

NOTE: To repeat the fault the APU must be cold soaked.
4. Fault Isolation
Subtask 49-00-81-810-110-A ** ON A/C NOT FOR ALL
A. If the APU SHUTDOWN report gives the maintenance message:

NO ACCELERATION
APU OIL HEATER P7

associated with the Fault Code Number (FCN) 115

  • do a check for 115 VAC at the APU OIL HEATER (P28) ASM 496104:
NOTE: Make sure that:
  • the APU MASTER SW P/BSW on the panel 25VU is OFF,
  • the circuit breaker OIL HEATER (1KT) on the circuit breaker panel (121VU) is closed.
  • the 115 VAC power supply at the SERVICE BUS 2 (214XP-B) is correct.
   (1) If there is a ground signal and 115 VAC:
   (2) If there is no ground signal:
  • do a check and repair of the wiring from the APU OIL HEATER (P28) P28/2 to GND ASM 496104.
   (3) If there is no 115 VAC:
  • replace the APU MAIN RELAY (32KD)
NOTE: The APU MAIN RELAY (32KD) is installed in the CONTACTOR BOX (107VU).
     (a) If the fault continues:
  • do a check and repair of the wiring from the APU OIL HEATER (P28) P28/2 to GND ASM 496104.
     (b) If the fault continues:
Subtask 49-00-81-810-110-B ** ON A/C NOT FOR ALL
A. If the APU SHUTDOWN report gives the maintenance message:

NO ACCELERATION
APU OIL HEATER (8093KM)

associated with the Fault Code Number (FCN) 115

  • do a check for 115 VAC at the APU OIL HEATER (8093KM) ASM 496104:
NOTE: Make sure that:
  • the APU MASTER SW P/BSW on the panel 25VU is OFF,
   (1) Make sure that the oil heater is installed on the APU and the Oil Heater System is activated.
     (a) If the oil heater is not installed, replace the cover plate by the oil heater AMM 49-96-51-960-001.
     (b) If the oil heater is not activated, do the activation procedure AMM 49-96-00-440-001.
   (2) 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:
       1 use a MULTIMETER - STANDARD to do a resistance check across pin 1 and pin 3 of the APU OIL HEATER (8093KM).
         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).
     (c) 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.
       1 If the fault continues:
  • replace the P/BSW-APU/MASTER SW [14KD]
       2 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.
       3 If the fault continues:
   (3) If the fault continues:
Subtask 49-00-81-710-155-A ** ON A/C NOT FOR ALL
B. After the subsequent flight, make sure that the fault does not continue.
NOTE: Make sure that:
  • the cruise phase of the flight was more than 4 hours,
  • the APU was not started during the flight phase.
[Rev.8 from Aug 2018] 2026.04.04 04:34:34 UTC
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