DOC AIRBUS | TSM A320FFailure of the Auxiliary Control Circuit of the External Power
TASK 24-41-00-810-816-A
Failure of the Auxiliary Control Circuit of the External Power
1. Possible Causes
2. Job Set-up Information
A. Referenced Information
3. Fault Confirmation
Subtask 24-41-00-740-054-A ** ON A/C NOT FOR ALL 4. Fault Isolation
Subtask 24-41-00-810-061-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:26:54 UTC
Failure of the Auxiliary Control Circuit of the External Power
1. Possible Causes
2. Job Set-up Information
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| ASM 242302 | |
| AMM 24-41-00-740-002 | Operational Check of the GAPCU via the CFDS |
| AMM 24-41-34-000-001 | Removal of the Ground Power Control Unit (GPCU) |
| AMM 24-41-34-400-001 | Installation of the Ground Power Control Unit (GPCU) |
Subtask 24-41-00-740-054-A ** ON A/C NOT FOR ALL 4. Fault Isolation
Subtask 24-41-00-810-061-A ** ON A/C NOT FOR ALL
A. If the BITE test gives the maintenance message GAPCU (24XG)/ EXT PWR AUX RELAY (5XG):
Subtask 24-41-00-740-055-A ** ON A/C NOT FOR ALL - do a check of the coil and contacts of the EPC auxiliary control relay (5XG) ASM 242302 for correct electrical continuity between:
. pins X1 and X2 (coil resistance)
. pins D2 and D3 (normally closed)
. pins D2 and D1 (normally open)
. pins C2 and C3 (normally closed)
. pins C2 and C1 (normally open).
- replace the RELAY-EPC AUX CTL [5XG] .
- do a check of the wiring of the EPC control circuit ASM 242302 for an open circuit or a short to ground between:
. pin A/X2 of the EPC auxiliary control relay (5XG) and pin B/10A of the GAPCU
. pin A/X1 of the EPC auxiliary control relay and pin 2 of the ELEC/EXT PWR/CTL circuit breaker (11XG).
- repair or replace as necessary.
- replace the GAPCU [24XG] AMM 24-41-34-000-001 and AMM 24-41-34-400-001.
B. Do the test given in Para. 3.