DOC AIRBUS | TSM A320FFCU Bus Fault on EIU-1
TASK 73-25-00-810-A08-A
FCU Bus Fault on EIU-1
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 73-25-00-710-443-A ** ON A/C NOT FOR ALL
Subtask 73-25-00-810-269-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:36:25 UTC
FCU Bus Fault on EIU-1
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | MULTIMETER - STANDARD |
| No specific | 1 | PLIERS - JAWED, SOFT |
| REFERENCE | DESIGNATION |
|---|---|
| AMM 22-81-12-000-001 | Removal of the FCU |
| AMM 22-81-12-400-001 | Installation of the FCU |
| AWM 228628 | |
| AWM 732517 | |
| AMM 73-25-34-000-802 | Removal of the Engine Interface Unit (EIU) |
| AMM 73-25-34-400-802 | Installation of the Engine Interface Unit (EIU) |
| AMM 73-25-34-710-802 | Operational Test of the Engine Interface Unit (EIU) with the Centralized Fault Display System (CFDS) |
Subtask 73-25-00-710-443-A ** ON A/C NOT FOR ALL
A. Do the operational test of the Engine Interface Unit (EIU) with the Centralized Fault Display System (CFDS) to confirm this fault AMM 73-25-34-710-802.
4. Fault IsolationSubtask 73-25-00-810-269-A ** ON A/C NOT FOR ALL
A. If there is confirmation of the fault:
(1) Remove EIU-1 [1KS1] AMM 73-25-34-000-802.
(2) Remove FCU [2CA] AMM 22-81-12-000-001.
(a) Use a PLIERS - JAWED, SOFT to disconnect connector A.
(3) Use a MULTIMETER - STANDARD to test the EIU/FCU circuits in the harness AWM 732517 and AWM 228628. Refer to Table 1. Look for:
(a) Wire-to-wire shorts
(b) Shorts to ground
(c) Continuity (less than 5 ohms resistance).
Table 1: EIU/FCU Connector Contacts
(4) If a problem is found, repair or replace the wiring AWM 732517 and AWM 228628.
(a) Do the test given in Para. 3.
(5) If no problem is found or if fault continues:
(a) Replace FCU [2CA] AMM 22-81-12-400-001.
(b) Do the test given in Para. 3.
(6) If no problem is found or if fault continues:
(a) Replace EIU-1 [1KS1] AMM 73-25-34-400-802.
(b) Do the test given in Para. 3.
(1) Remove EIU-1 [1KS1] AMM 73-25-34-000-802.
(2) Remove FCU [2CA] AMM 22-81-12-000-001.
(a) Use a PLIERS - JAWED, SOFT to disconnect connector A.
(3) Use a MULTIMETER - STANDARD to test the EIU/FCU circuits in the harness AWM 732517 and AWM 228628. Refer to Table 1. Look for:
(a) Wire-to-wire shorts
(b) Shorts to ground
(c) Continuity (less than 5 ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.
Table 1: EIU/FCU Connector Contacts
| FCU (2CA) Connector A Contacts | EIU-1 (1KS1) Connector AA Contacts |
|---|---|
| DD | 1J |
| <M | 1J |
| EE | 1K |
| <N | 1K |
(a) Do the test given in Para. 3.
(5) If no problem is found or if fault continues:
(a) Replace FCU [2CA] AMM 22-81-12-400-001.
(b) Do the test given in Para. 3.
(6) If no problem is found or if fault continues:
(a) Replace EIU-1 [1KS1] AMM 73-25-34-400-802.
(b) Do the test given in Para. 3.