DOC AIRBUS | TSM A320FTRA Signal Failure Channel A
TASK 76-11-00-810-825-A
TRA Signal Failure Channel A
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 76-11-00-710-096-A ** ON A/C NOT FOR ALL
Subtask 76-11-00-860-054-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:40:50 UTC
TRA Signal Failure 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 |
| AMM 70-70-00-910-803 | SPOP 6 - Cleaning of the Contact Points and Wiring Harnesses |
| 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 732541 | |
| AWM 732542 | |
| AMM 76-11-51-000-802 | Removal of the Throttle Control Unit |
| AMM 76-11-51-400-802 | Installation of the Throttle Control Unit |
| AMM 78-36-00-010-802 | Opening of the Thrust Reverser Cowl-Doors |
| AMM 78-36-00-410-802 | Closing of the Thrust Reverser Cowl-Doors |
EEC Wiring HarnessesSubtask 76-11-00-710-096-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) in channel A, go to the Para. Fault Isolation.
4. Fault IsolationNOTE: The Electronic Engine Control (EEC) has detected that the Throttle Resolver Angle (TRA) circuit for the Throttle Control Unit (TCU) is out of range or rate in channel A. The Throttle Control Unit is located in the cockpit.
(1) 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.
(2) If the maintenance message comes back (hard fault) in channel A, 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 76-11-00-810-082-A ** ON A/C NOT FOR ALL A. If there is confirmation of the fault:
(1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Replace CTL UNIT-THROTTLE, ENG 1 [8KS1] or CTL UNIT-THROTTLE, ENG 2 [8KS2] AMM 76-11-51-000-802 and AMM 76-11-51-400-802.
(a) Do the test given in Para. 3.
(3) If the fault continues:
(a) Examine the WF02 (4218KS) harness, connector P1 (4000KS-P1) - EEC (4000KS) and connector P406 (406VC-A) - Pylon junction box, for problems which are possible between the EEC (4000KS) and the pylon junction box.
1 Inspect for harnesses damage.
2 Inspect for loose or damaged connectors.
a Replace 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.
(4) 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 P406 (406VC-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 P406 (406VC-A) to the pylon junction box.
(d) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P1 (4000KS-P1) from the EEC (4000KS) and connector P406 (406VC-A) from the pylon junction box. Use a MULTIMETER - STANDARD to test the TRA circuits 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.
(6) If the fault continues:
(a) Do a check of the aircraft wiring from the TCU (8KS) to the pylon junction box (406VC).
- For fault on ENG 1, refer to AWM 732541.
- For fault on ENG 2, refer to AWM 732542.
1 Refer to Table 2. Look for:
2 Repair wiring as necessary
3 Do the test given in Para. 3.
(7) If the fault continues:
(a) Replace
(b) Do the test given in Para. 3.
5. Close-up(1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Replace CTL UNIT-THROTTLE, ENG 1 [8KS1] or CTL UNIT-THROTTLE, ENG 2 [8KS2] AMM 76-11-51-000-802 and AMM 76-11-51-400-802.
(a) Do the test given in Para. 3.
(3) If the fault continues:
(a) Examine the WF02 (4218KS) harness, connector P1 (4000KS-P1) - EEC (4000KS) and connector P406 (406VC-A) - Pylon junction box, for problems which are possible between the EEC (4000KS) and the pylon junction box.
1 Inspect for harnesses 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 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.
(4) 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 P406 (406VC-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 P406 (406VC-A) to the pylon junction box.
(d) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P1 (4000KS-P1) from the EEC (4000KS) and connector P406 (406VC-A) from the pylon junction box. Use a MULTIMETER - STANDARD to test the TRA circuits 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: TRA Channel A Circuit Connector Contacts | WF02 (4218KS) Harness P1 (4000KS-P1) EEC (4000KS) Connector Contacts | WF02 (4218KS) Harness P406 (406VC-A) Pylon Junction Box Connector Contacts |
|---|---|
| CC | 3 |
| BB | 12 |
| AA | 13 |
| z | 14 |
| g | 15 |
| F | 5 |
(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.
(6) If the fault continues:
(a) Do a check of the aircraft wiring from the TCU (8KS) to the pylon junction box (406VC).
- For fault on ENG 1, refer to AWM 732541.
- For fault on ENG 2, refer to AWM 732542.
1 Refer to Table 2. Look for:
- Wire-to-wire shorts
- Shorts to ground
- Continuity (less than 5 ohms resistance).
Table 2: Aircraft Wiring Channel A Circuit Connector Contacts
| (406VC-A) Pylon Junction Box Connector Contacts | TCU (8KS) Connector C |
|---|---|
| 3 | B |
| 12 | A |
| 13 | C |
| 14 | D |
| 15 | E |
| 5 | F |
2 Repair wiring as necessary
3 Do the test given in Para. 3.
(7) If the fault continues:
(a) Replace
(b) Do the test given in Para. 3.
Subtask 76-11-00-860-054-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 thrust reverser cowl-doors AMM 78-36-00-410-802.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the thrust reverser cowl-doors AMM 78-36-00-410-802.