Unwanted AC ESS BUS FAULT Warning

TASK 24-50-00-810-803-A
Unwanted AC ESS BUS FAULT Warning

1. Possible Causes

SDAC-1 [1WV1]
SDAC-2 [1WV2]
3XH
wiring
C/B-AC ESS BUS/MONG/SPLY [2XH]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 24-00-00-810-803-A	Circuit Breaker Tripped and/or C/B TRIPPED Warning
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
ASM 245201
AMM 31-55-34-000-001	Removal of the SDAC
AMM 31-55-34-400-001	Installation of the SDAC
AMM 31-60-00-860-001	EIS Start Procedure

3. Fault Confirmation
Subtask 24-50-00-860-054-A

A. Job Set-up
(1) Aircraft Maintenance Configuration
(a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.

Subtask 24-50-00-710-054-A

B. Test
(1) Do the EIS start procedure to make sure that the EIS operates correctly AMM 31-60-00-860-001.
(2) Do this test:

ACTION	RESULT
1.On the ECAM control panel: Push the ELEC key to get the ELEC page.	On the lower ECAM DU, on the ELEC page: The normal configuration comes into view with the AC ESS indication shown in amber.
	On the upper ECAM DU: The ELEC AC ESS BUS FAULT warning comes into view.

4. Fault Isolation
Subtask 24-50-00-810-052-A

A. If the test gives the ELEC AC ESS BUS FAULT warning on the upper ECAM DU when the EIS operates correctly:

Do a check of the status of the AC ESS BUS/MONG/SPLY circuit breaker (2XH).

(1) If the circuit breaker is closed:

Remove SDAC1 AMM 31-55-34-000-001.

(a) If the fault does not continue:

Replace SDAC-1 [1WV1] AMM 31-55-34-400-001.

(b) If the fault continues:

Install SDAC1 AMM 31-55-34-400-001.
Remove SDAC2 AMM 31-55-34-000-001.

1 If the fault does not continue:

Replace SDAC-2 [1WV2] AMM 31-55-34-400-001.

2 If the fault continues:

Install SDAC2 AMM 31-55-34-400-001.
Replace relay 3XH .

a If the fault continues:

Do a check for continuity and repair the wiring between:
. The AC ESS BUS/MONG/SPLY circuit breaker (2XH) and pin A/X of the bus 4XP control relay (3XH)
. Pin A/Z of the bus 4XP control relay (3XH) and the ground.
Do a check for a short to ground and for a short circuit of the wiring between:
. Pin A/A of the bus 4XP control relay (3XH) and pins AD/5E of SDAC1 and 2, ASM 245201.

(2) If the circuit breaker is open:

Do the trouble shooting procedure (Ref. TSM TASK 24-00-00-810-803).

(a) If the fault continues:

Replace relay 3XH .

1 If the fault continues:
Replace C/B-AC ESS BUS/MONG/SPLY [2XH] .

Subtask 24-50-00-710-055-A

B. Do this test to make sure that the system operates correctly:

ACTION	RESULT
1.On the ECAM control panel: Push the ELEC key to get the ELEC page.	On the lower ECAM DU, on the ELEC page: The normal configuration comes into view.
	On the upper ECAM DU: No message comes into view.

5. Close-up
Subtask 24-50-00-860-055-A

A. Put the aircraft back to its initial configuration.
(1) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:55 UTC