DOC AIRBUS | TSM A320FBMC-1 and BMC-2 buses fault on EIU-2
TASK 73-25-00-810-C67-A
BMC-1 and BMC-2 buses fault on EIU-2
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 73-25-00-710-716-A ** ON A/C NOT FOR ALL
Subtask 73-25-00-810-668-A ** ON A/C NOT FOR ALL
Subtask 73-25-00-860-313-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:36:56 UTC
BMC-1 and BMC-2 buses fault on EIU-2
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | MULTIMETER - STANDARD |
| REFERENCE | DESIGNATION |
|---|---|
| AWM 361111 | |
| AWM 361112 | |
| AMM 36-11-34-000-001 | Removal of the BMC |
| AMM 36-11-34-400-001 | Installation of the BMC |
| 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) |
| AWM 732557 | |
| AWM 732558 |
Subtask 73-25-00-710-716-A ** ON A/C NOT FOR ALL
A. Do the operational test of the Engine Interface Unit (EIU) (1KS2) with the Centralized Fault Display System (CFDS) to confirm this fault. Refer to AMM 73-25-34-710-802.
4. Fault IsolationSubtask 73-25-00-810-668-A ** ON A/C NOT FOR ALL
A. Do as follows:
(1) Do the operational test of the EIU-1 (1KS1) with the CFDS to confirm this fault. Refer to AMM 73-25-34-710-802.
(2) If the fault is confirmed on EIU-1 (1KS1) and EIU-2 (1KS2):
(a) Replace BMC-1 [1HA1] and BMC-2 [1HA2] AMM 36-11-34-000-001 and AMM 36-11-34-400-001.
(b) Do the test given in Para. 3.
(c) If the fault continues:
1 Remove BMC-1 [1HA1] and BMC-2 [1HA2] AMM 36-11-34-000-001.
2 Use a MULTIMETER - STANDARD to do test of the circuits AWM 732557, AWM 361111 and AWM 361112. Refer to Table 1 and Table 2. Look for:
3 Wire-to-wire shorts
4 Shorts to ground
5 Continuity (less than 5 ohms resistance).
Table 1: BMC-1 Circuit Connector Contacts
Table 2: BMC-2 Circuit Connector Contacts
(3) If a problem is found repair or replace wiring .
(a) Install BMC-1 [1HA1] and BMC-2 [1HA2] AMM 36-11-34-400-001.
(b) Do the test given in Para. 3.
(4) If no problem is found or if the fault continues:
(a) Remove EIU-2 [1KS2] AMM 73-25-34-000-802.
(b) Use a MULTIMETER - STANDARD to do test of the circuits AWM 732557 and AWM 732558. Refer to Table 3. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).
Table 3: EIU-2 Circuit Connector Contacts
(5) If a problem is found repair or replace wiring .
(6) If no problem is found or if the fault continues:
(a) Replace EIU-2 [1KS2] AMM 73-25-34-400-802.
(b) Do the test given in Para. 3.
5. Close-up(1) Do the operational test of the EIU-1 (1KS1) with the CFDS to confirm this fault. Refer to AMM 73-25-34-710-802.
(2) If the fault is confirmed on EIU-1 (1KS1) and EIU-2 (1KS2):
(a) Replace BMC-1 [1HA1] and BMC-2 [1HA2] AMM 36-11-34-000-001 and AMM 36-11-34-400-001.
(b) Do the test given in Para. 3.
(c) If the fault continues:
1 Remove BMC-1 [1HA1] and BMC-2 [1HA2] AMM 36-11-34-000-001.
2 Use a MULTIMETER - STANDARD to do test of the circuits AWM 732557, AWM 361111 and AWM 361112. Refer to Table 1 and Table 2. Look for:
3 Wire-to-wire shorts
4 Shorts to ground
5 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: BMC-1 Circuit Connector Contacts
| BMC-1 (1HA1) Connector AA Contacts | 1862VT (86VU) Contacts |
|---|---|
| 13B | S |
| 15B | G |
Table 2: BMC-2 Circuit Connector Contacts
| BMC-2 (1HA2) Connector AA Contacts | 1862VT (86VU) Contacts |
|---|---|
| 13B | Y |
| 15B | S |
(a) Install BMC-1 [1HA1] and BMC-2 [1HA2] AMM 36-11-34-400-001.
(b) Do the test given in Para. 3.
(4) If no problem is found or if the fault continues:
(a) Remove EIU-2 [1KS2] AMM 73-25-34-000-802.
(b) Use a MULTIMETER - STANDARD to do test of the circuits AWM 732557 and AWM 732558. Refer to Table 3. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.
Table 3: EIU-2 Circuit Connector Contacts
| EIU-2 (1KS2) Connector AA Contacts | 1862VT (86VU) Contacts |
|---|---|
| 14C | R |
| 15C | Y |
| 10F | P |
| 11E | T |
(6) If no problem is found or if the fault continues:
(a) Replace EIU-2 [1KS2] AMM 73-25-34-400-802.
(b) Do the test given in Para. 3.
Subtask 73-25-00-860-313-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(1) Make sure that the work area is clean and clear of tools and other items.