DOC AIRBUS | TSM A320FEIU Bus Data Failure Dual Channels
TASK 73-21-00-810-905-A
EIU Bus Data Failure Dual Channels
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 73-21-00-710-156-A ** ON A/C NOT FOR ALL
Subtask 73-21-00-860-094-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:36:42 UTC
EIU Bus Data Failure Dual Channels
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 |
|---|---|
| TSM TASK 71-00-00-810-834-A | General Troubleshooting Guidelines for Additional Troubleshooting Information |
| TSM TASK 71-00-00-810-835-A | Component and Harness Intermittent Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults |
| AMM 70-70-00-910-803 | SPOP 6 - Cleaning of the Contact Points and Wiring Harnesses |
| AMM 71-13-00-010-802 | Opening of the Fan Cowl Doors |
| AMM 71-13-00-410-802 | Closing of the Fan Cowl Doors |
| AMM 73-21-01-000-801 | Removal of the Electronic Engine Control (EEC) |
| AMM 73-21-01-400-801 | Installation of the Electronic Engine Control (EEC) |
| AMM 73-21-62-000-802 | Removal of the EEC Wiring Harness (WF02) |
| AMM 73-21-62-400-802 | Installation of the EEC Wiring Harness (WF02) |
| AWM 732524 | |
| AWM 732525 | |
| AMM 73-25-34-000-802 | Removal 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) |
EEC Wiring HarnessesSubtask 73-21-00-710-156-A ** ON A/C NOT FOR ALL
A. Turn on Power to the EEC
(1) On the ENG section of maintenance panel 50VU:
(a) Release the FADEC GND PWR/1(2) push button switch (the ON legend comes on).
(2) On the upper ECAM DU, check if ENG 1(2) EIU FAULT warning is shown.
(a) If no problems are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(4) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
4. Fault Isolation(1) On the ENG section of maintenance panel 50VU:
(a) Release the FADEC GND PWR/1(2) push button switch (the ON legend comes on).
(2) On the upper ECAM DU, check if ENG 1(2) EIU FAULT warning is shown.
NOTE: The ENG 1(2) EIU FAULT warning will also display if ENG1(2)D-1008-STARTING INPUT FAIL maintenance message is set. If ENG 1(2) EIU FAULT ECAM warning is shown, check the ground scanning report for the ENG1(2)D-1008-STARTING INPUT FAIL maintenance message. If the ENG1(2)D-1008-STARTING INPUT FAIL maintenance message appears, do the troubleshooting for that fault first.
NOTE: The Electronic Engine Control (EEC) channel A and channel B have detected that the Engine Interface Unit (EIU) circuits have failed. The EIU circuit is connected to the EEC channel A and cross-strapped to channel B within the EEC. The EEC is located on the fan case at the 2 o'clock position.
(3) If the maintenance message does not come back, examine the harnesses and electrical connectors as described in the component and harness intermittent fault isolation procedure (Ref. TSM TASK 71-00-00-810-835). - Refer to the general troubleshooting guidelines for additional troubleshooting information (Ref. TSM TASK 71-00-00-810-834).
- Refer to the component and harness intermittent troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-835).
(a) If no problems are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(4) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.
WARNING:
REFER TO THE MSDS FOR ALL MATERIAL USED AND THE MANUFACTURER'S SAFETY INSTRUCTIONS FOR ALL EQUIPMENT USED. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.
CAUTION:
MAKE SURE YOU REMOVE ELECTRICAL POWER FROM THE EEC BEFORE YOU REMOVE THE ELECTRICAL CONNECTORS. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EEC CAN OCCUR.
Subtask 73-21-00-810-174-A ** ON A/C NOT FOR ALL A. If there is confirmation of the fault:
(1) If the ECAM message ENG 1 EIU FAULT or ENG 2 EIU FAULT does not show, examine the harness and electrical connectors as described in the component and harness intermittent fault isolation procedure.
(a) If no problems are found, return the engine to service. Monitor the engine for reoccuring maintenance message.
(2) If the ECAM message ENG 1 EIU FAULT or ENG 2 EIU FAULT comes back (hard fault), perform troubleshooting in the next step.
(3) Check for EIU fault:
(a) Do an operational test of the EIU with the Centralized Fault Display System (CFDS) AMM 73-25-34-710-802.
(b) Check for any fault on EIU bus.
(c) If a fault is found, troubleshoot it.
(d) Do the test given in Para. 3.
(4) If no EIU fault is found or if EEC fault continues:
(a) Open the fan cowl doors AMM 71-13-00-010-802.
(b) Examine the WF02 (4218KS) harness, connector P1 (4000KS-P1) - EEC (4000KS), and connector P402 (402VC-A) - pylon junction box, for problems which are possible between the EEC (4000KS) and the pylon junction box.
1 Inspect for harness damage.
2 Inspect for loose or damaged connectors.
a Replace the HARNESS-FAN, WF02 [4218KS] AMM 73-21-62-000-802 and AMM 73-21-62-400-802.
b Do the test given in Para. 3.
(5) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P1 (4000KS-P1) from the EEC (4000KS) and connector P402 (402VC-A) from the pylon junction box.
(a) Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face. Replace parts as necessary.
(b) Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across connector face AMM 70-70-00-910-803.
(c) Reconnect the electrical connector P1 (4000KS-P1) to the EEC (4000KS) and connector P402 (402VC-A) to the pylon junction box.
(d) Do the test given in Para. 3.
(6) If the fault continues:
(a) Disconnect the electrical connector P1 (4000KS-P1) from the EEC (4000KS) and connector P402 (402VC-A) from the pylon junction box. Use a MULTIMETER - STANDARD to test the EIU circuit in the harness. Refer to Table 1. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).
(b) If a problem is found with the harness or connectors:
1 Replace the HARNESS-FAN, WF02 [4218KS] AMM 73-21-62-000-802 and AMM 73-21-62-400-802.
2 Do the test given in Para. 3.
(7) If no problems are found with the harness or the fault continues on ENG 1, do a check of the EIU-1 circuit in the aircraft wiring AWM 732524.
(a) At the pylon junction box, make sure that the connector 402VC1-A is disconnected.
(b) Remove EIU-1 [1KS1] AMM 73-25-34-000-802.
(c) At 85VU side, put a shunt between pins 5A and 5C at connector AB.
(d) At 402VC2, check for continuity between pins 4 and 12.
(e) At connector AB, remove the shunt
(f) At pins 5A and 5C, check for wire-to-wire short then short to ground.
(g) Repair aircraft wiring for any problem found AWM 732524.
(h) Connect connector 402VC2-A then do the test given in Para. 3.
(8) If no problems were found with the harness or the fault continues on ENG 2, do a check of the EIU-2 circuit in the aircraft wiring AWM 732525.
(a) At the pylon junction box, make sure that the connector 402VC2-A is disconnected.
(b) Remove EIU-2 [1KS2] AMM 73-25-34-000-802.
(c) At 86VU side, put a shunt between pins 5A and 5C at connector AB.
(d) At 402VC1, check for continuity between pins 4 and 12.
(e) At connector AB, remove the shunt.
(f) At pins 5A and 5C, check for wire-to-wire short then short to ground.
(g) Repair aircraft wiring for any problem found AWM 732525.
(h) Connect connector 402VC1-A then do the test given in Para. 3.
(9) If no problems are found with the aircraft wiring or the fault continues:
(a) Replace
(b) Do the test given in Para. 3.
Subtask 73-21-00-710-432-A ** ON A/C NOT FOR ALL (1) If the ECAM message ENG 1 EIU FAULT or ENG 2 EIU FAULT does not show, examine the harness and electrical connectors as described in the component and harness intermittent fault isolation procedure.
(a) If no problems are found, return the engine to service. Monitor the engine for reoccuring maintenance message.
(2) If the ECAM message ENG 1 EIU FAULT or ENG 2 EIU FAULT comes back (hard fault), perform troubleshooting in the next step.
(3) Check for EIU fault:
(a) Do an operational test of the EIU with the Centralized Fault Display System (CFDS) AMM 73-25-34-710-802.
(b) Check for any fault on EIU bus.
(c) If a fault is found, troubleshoot it.
(d) Do the test given in Para. 3.
(4) If no EIU fault is found or if EEC fault continues:
(a) Open the fan cowl doors AMM 71-13-00-010-802.
(b) Examine the WF02 (4218KS) harness, connector P1 (4000KS-P1) - EEC (4000KS), and connector P402 (402VC-A) - pylon junction box, for problems which are possible between the EEC (4000KS) and the pylon junction box.
1 Inspect for harness damage.
2 Inspect for loose or damaged connectors.
NOTE: Loose connectors must be disconnected and examined for further wear or damage.
3 If a problem is found with the harness or connectors: a Replace the HARNESS-FAN, WF02 [4218KS] AMM 73-21-62-000-802 and AMM 73-21-62-400-802.
b Do the test given in Para. 3.
(5) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P1 (4000KS-P1) from the EEC (4000KS) and connector P402 (402VC-A) from the pylon junction box.
(a) Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face. Replace parts as necessary.
(b) Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across connector face AMM 70-70-00-910-803.
(c) Reconnect the electrical connector P1 (4000KS-P1) to the EEC (4000KS) and connector P402 (402VC-A) to the pylon junction box.
(d) Do the test given in Para. 3.
(6) If the fault continues:
(a) Disconnect the electrical connector P1 (4000KS-P1) from the EEC (4000KS) and connector P402 (402VC-A) from the pylon junction box. Use a MULTIMETER - STANDARD to test the EIU circuit in the harness. Refer to Table 1. 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 1: EEC to Pylon Junction Box EIU Circuit Channel A Connector Contacts | WF02 (4218KS) Harness P1 (4000KS-P1) EEC (4000KS) Connector Contacts | WF02 (4218KS) Harness P402 (402VC-A) Pylon Junction Box Connector Contacts |
|---|---|
| GG | 4 |
| HH | 12 |
1 Replace the HARNESS-FAN, WF02 [4218KS] AMM 73-21-62-000-802 and AMM 73-21-62-400-802.
2 Do the test given in Para. 3.
(7) If no problems are found with the harness or the fault continues on ENG 1, do a check of the EIU-1 circuit in the aircraft wiring AWM 732524.
(a) At the pylon junction box, make sure that the connector 402VC1-A is disconnected.
(b) Remove EIU-1 [1KS1] AMM 73-25-34-000-802.
(c) At 85VU side, put a shunt between pins 5A and 5C at connector AB.
(d) At 402VC2, check for continuity between pins 4 and 12.
(e) At connector AB, remove the shunt
(f) At pins 5A and 5C, check for wire-to-wire short then short to ground.
(g) Repair aircraft wiring for any problem found AWM 732524.
(h) Connect connector 402VC2-A then do the test given in Para. 3.
(8) If no problems were found with the harness or the fault continues on ENG 2, do a check of the EIU-2 circuit in the aircraft wiring AWM 732525.
(a) At the pylon junction box, make sure that the connector 402VC2-A is disconnected.
(b) Remove EIU-2 [1KS2] AMM 73-25-34-000-802.
(c) At 86VU side, put a shunt between pins 5A and 5C at connector AB.
(d) At 402VC1, check for continuity between pins 4 and 12.
(e) At connector AB, remove the shunt.
(f) At pins 5A and 5C, check for wire-to-wire short then short to ground.
(g) Repair aircraft wiring for any problem found AWM 732525.
(h) Connect connector 402VC1-A then do the test given in Para. 3.
(9) If no problems are found with the aircraft wiring or the fault continues:
(a) Replace
(b) Do the test given in Para. 3.
B. Repair Confirmation
(1) Turn on Power to the EEC
(a) On the ENG section of maintenance panel 50VU:
1 Release the FADEC GND PWR/1(2) push button switch (the ON legend comes on).
(b) On the upper ECAM DU, make sure that ENG 1(2) EIU FAULT warning does not show.
1 If ENG 1(2) EIU FAULT warning does not show, you have fixed the fault.
5. Close-up(1) Turn on Power to the EEC
(a) On the ENG section of maintenance panel 50VU:
1 Release the FADEC GND PWR/1(2) push button switch (the ON legend comes on).
(b) On the upper ECAM DU, make sure that ENG 1(2) EIU FAULT warning does not show.
1 If ENG 1(2) EIU FAULT warning does not show, you have fixed the fault.
NOTE: The ENG 1(2) EIU FAULT warning will also display if STARTING INPUT FAIL maintenance message is set. If ENG 1(2) EIU FAULT ECAM warning is shown, check the ground scanning report for the STARTING INPUT FAIL maintenance message. If the STARTING INPUT FAIL maintenance message appears, do the troubleshooting for that fault. If ENG 1(2) EIU FAULT ECAM warning is shown and STARTING INPUT FAIL maintenance message does not appear, you have not fixed the fault.
Subtask 73-21-00-860-094-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.
(a) Close the fan cowl doors AMM 71-13-00-410-802.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.