DOC AIRBUS | TSM A320FARINC Out Bus Wraparound Failure (Transmitters TX2 Wraparound Signal Failures) Channel A
TASK 73-21-00-810-887-A
ARINC Out Bus Wraparound Failure (Transmitters TX2 Wraparound Signal Failures) Channel A
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 73-21-00-710-140-A ** ON A/C NOT FOR ALL
Subtask 73-21-00-860-079-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:36:41 UTC
ARINC Out Bus Wraparound Failure (Transmitters TX2 Wraparound Signal Failures) Channel A
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 |
| AWM 228604 | |
| AWM 242207 | |
| AWM 242208 | |
| AWM 315214 | |
| AWM 316217 | |
| AWM 316218 | |
| 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 73-21-00-710-806 | Test No.7 - EEC Operation Test (Self Test) |
| 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 732526 | |
| AWM 732527 | |
EEC Wiring HarnessesSubtask 73-21-00-710-140-A ** ON A/C NOT FOR ALL
A. Do the EEC system interactive test to confirm this fault. Refer to FADEC self test AMM 73-21-00-710-806.
(a) If no problems are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(2) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
4. Fault IsolationNOTE: The Electronic Engine Control (EEC) has detected that the ARINC Output Bus 2 circuit is shorted in channel A. The ARINC Output Bus 2 circuit is between the EEC and the aircraft computer. The EEC is located on the fan case at the 2 o'clock position.
(1) If the maintenance message does not come back, examine the harness 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.
(2) 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 73-21-00-810-159-A ** ON A/C NOT FOR ALL A. If there is confirmation of the fault:
(1) Open the fan cowl-doors AMM 71-13-00-010-802.
(2) 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.
(a) Inspect for harness damage.
(b) Inspect for loose or damaged 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.
(3) 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.
(4) 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 ARINC Output Bus 2 channel A 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.
(5) If no problems are found with the harness or the fault continues:
(a) Disconnect electrical connector (402VC-A).
(b) Do a check of the aircraft wiring containing the ARINC Output Bus 2 channel A circuit from the aircraft computers to the pylon junction box at contact 36 and 18 of electrical connector (402VC):
1 For fault of ENG 1: refer to AWM 732527, AWM 228604, AWM 242207, AWM 315214 and AWM 316217.
2 For fault of ENG 2: refer to AWM 732526, AWM 228604, AWM 242208, AWM 315214 and AWM 316218.
3 Look for:
a Replace or repair aircraft wiring .
b Reconnect all connectors.
c Do the test given in Para. 3.
(6) If the fault continues:
(a) Replace
(b) Make sure that all connectors are reconnected.
(c) Do the test given in Para. 3.
5. Close-up(1) Open the fan cowl-doors AMM 71-13-00-010-802.
(2) 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.
(a) Inspect for harness damage.
(b) Inspect for loose or damaged connectors.
NOTE: Loose connectors must be disconnected and examined for further wear or damage.
(c) 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.
(3) 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.
(4) 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 ARINC Output Bus 2 channel A 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: ARINC Output Bus 2 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 |
|---|---|
| c | 36 |
| B | 18 |
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.
(5) If no problems are found with the harness or the fault continues:
(a) Disconnect electrical connector (402VC-A).
(b) Do a check of the aircraft wiring containing the ARINC Output Bus 2 channel A circuit from the aircraft computers to the pylon junction box at contact 36 and 18 of electrical connector (402VC):
1 For fault of ENG 1: refer to AWM 732527, AWM 228604, AWM 242207, AWM 315214 and AWM 316217.
2 For fault of ENG 2: refer to AWM 732526, AWM 228604, AWM 242208, AWM 315214 and AWM 316218.
3 Look for:
- Wire-to-wire shorts
- Shorts to ground
- Continuity (less than 5 ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100 000 (100k) ohms.
4 If you find damage: a Replace or repair aircraft wiring .
b Reconnect all connectors.
c Do the test given in Para. 3.
(6) If the fault continues:
(a) Replace
(b) Make sure that all connectors are reconnected.
(c) Do the test given in Para. 3.
Subtask 73-21-00-860-079-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.