APU AUTO SHUTDOWN - LOW OIL PRESSURE, Loss of Oil Pressure (131-9(A))

TASK 49-00-81-810-819-A
APU AUTO SHUTDOWN - LOW OIL PRESSURE, Loss of Oil Pressure (131-9(A))

1. Possible Causes

NO LRU FAULT DETECTED
oil level
LOW OIL PRESSURE SWITCH (P14)
DEOIL SOLENOID (P15)
OIL LUBE MODULE
LOW OIL PRESSURE SWITCH (8091KM)
DEOIL SOLENOID (8083KM)
OIL LUBE MODULE (8080KM)

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 49-00-81-810-867-A	Low-Oil Level (131-9(A))
AMM 49-00-00-860-008	APU Start by External Power
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 49-91-45-000-003	Removal of Oil Lube Module (131-9(A))
AMM 49-91-45-400-003	Installation of Oil Lube Module (131-9(A))
AMM 49-91-49-000-003	Removal of De-Oil Solenoid (131-9(A))
AMM 49-91-49-400-003	Installation of De-Oil Solenoid (131-9(A))
AMM 49-94-14-000-003	Removal of the Low Oil Pressure Switch (131-9(A))
AMM 49-94-14-400-003	Installation of the Low Oil Pressure Switch (131-9(A))

3. Fault Confirmation
Subtask 49-00-81-710-126-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
NO LRU FAULT DETECTED

(4) Do the subsequent check and the operational test of the APU:
(a) Do a check of the oil level in the APU oil reservoir AMM 49-90-00-600-007.

if you add more than 1 liter do the low oil-level condition trouble shooting (Ref. TSM TASK 49-00-81-810-867).

(b) Do the operational test of the APU AMM 49-00-00-860-008:

NOTE: Operate the APU for min. 15 minutes under full load. This makes sure that the oil temperature increases sufficiently.

4. Fault Isolation
Subtask 49-00-81-810-095-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
LOP SW P14 / OIL PUMP / DEOIL SOLENOID P15

associated with the Fault Code Number (FCN) 208

replace the LOW OIL PRESSURE SWITCH (P14) AMM 49-94-14-000-003 and AMM 49-94-14-400-003.

(1) If the fault continues:

replace the DEOIL SOLENOID (P15) AMM 49-91-49-000-003 and AMM 49-91-49-400-003.

(2) If the fault continues:

replace the OIL LUBE MODULE AMM 49-91-45-000-003 and AMM 49-91-45-400-003.

(3) If the fault continues:

replace the ECB (59KD) AMM 49-61-34-000-003 and AMM 49-61-34-400-003.

Subtask 49-00-81-810-133-A ** ON A/C NOT FOR ALL

B. If no APU auto-shutdown occurs during the operational test of the APU and the low oil pressure shutdown occured when the APU was cold soaked:

replace the DE-OELING SOLENOID VALVE (P15) AMM 49-91-49-000-003 and AMM 49-91-49-400-003.

Subtask 49-00-81-810-095-B ** ON A/C NOT FOR ALL

C. If an APU auto shutdown occurs during the APU operation and the APU SHUTDOWN report gives the maintenance message:

LOW OIL PRESSURE
LOP SW(8091KM)/OIL PUMP (8080KM)/DEOIL (8083KM)

associated with the Fault Code Number (FCN) 208

replace the LOW OIL PRESSURE SWITCH (8091KM) AMM 49-94-14-000-003 and AMM 49-94-14-400-003.

(1) If the fault continues:

replace the DEOIL SOLENOID (8083KM) AMM 49-91-49-000-003 and AMM 49-91-49-400-003.

(2) If the fault continues:

replace the OIL LUBE MODULE (8080KM) AMM 49-91-45-000-003 and AMM 49-91-45-400-003.

(3) If the fault continues:

replace the ECB (59KD) AMM 49-61-34-000-003 and AMM 49-61-34-400-003.

Subtask 49-00-81-810-133-B ** ON A/C NOT FOR ALL

D. If no APU auto-shutdown occurs during the operational test of the APU and the low oil pressure shutdown occured when the APU was cold soaked:

replace the DE-OELING SOLENOID VALVE (8083KM) AMM 49-91-49-000-003 and AMM 49-91-49-400-003.

Subtask 49-00-81-710-127-A ** ON A/C NOT FOR ALL

E. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:33 UTC