APU Indications on the ECAM after APU Usual Shutdown

TASK 49-61-00-810-816-A
APU Indications on the ECAM after APU Usual Shutdown

1. Possible Causes

RELAY-APU MAIN CTL [4KD]
P/BSW-APU/MASTER SW [14KD]
ELECTRONIC CONTROL BOX [59KD]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 496101
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))

3. Fault Confirmation
Subtask 49-61-00-710-078-A ** ON A/C NOT FOR ALL

A. Test
(1) On overhead panel 25VU, push the APU MASTER SW P/BSW (the ON legend goes on).
(2) On the lower ECAM display unit, select the APU page.
(3) Make sure that the APU indications on the APU page are correctly shown:

The N% indication is 0%.
The EGT value agrees with the ambient temperature.
The FLAP OPEN message is shown in green color when the air intake flap is fully open.

(4) On overhead panel 25VU, release the APU MASTER SW P/BSW to de-energize the ECB (the ON legend goes off and the air intake flap closes).
(5) On the lower ECAM display unit, when the FLAP OPEN message goes out of view, examine the APU indications on the APU page.
(a) If there are no APU indications and no EGT value is shown, no maintenance procedure is necessary.
(b) If there are APU indications and the EGT value is shown, the fault is confirmed.

4. Fault Isolation
Subtask 49-61-00-810-074-A ** ON A/C NOT FOR ALL

A. If the test confirms the fault:
(1) Do a check for 28VDC at pin AC/7 of the ECB ASM 496101
(a) If there is 28VDC, replace the RELAY-APU MAIN CTL [4KD] .

Subtask 49-61-00-810-075-A ** ON A/C NOT FOR ALL

B. If the fault continues:
(1) Replace the P/BSW-APU/MASTER SW [14KD] .
(2) Make sure that APU MASTER SW P/BSW is released (the ON legend is off).

Subtask 49-61-00-810-076-A ** ON A/C NOT FOR ALL

C. If the fault continues:
(1) Replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-003 and AMM 49-61-34-400-003.

[Rev.8 from Aug 2018] 2026.04.04 04:34:41 UTC