DOC AIRBUS | TSM A320FRTT Valve Stuck Open
TASK 73-13-00-810-803-A
RTT Valve Stuck Open
1. Possible Causes
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 73-13-00-710-052-A ** ON A/C NOT FOR ALL
Subtask 73-13-00-860-052-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:36:37 UTC
RTT Valve Stuck Open
1. Possible Causes
- FUEL RETURN TO TANK MODULE [4082KS]
- W04 HARNESS [4088KS]
- W03 HARNESS [4087KS]
- HARNESS-CORE,WC11 [4072KS]
[4000KS]
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 71-00-00-860-825 | Motor the Engine (Wet Method) |
| AMM 73-13-03-000-801 | Removal of the Fuel Return To Tank (RTT) Valve |
| AMM 73-13-03-400-801 | Installation of the Fuel Return To Tank (RTT) Valve |
| 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 73-21-63-000-802 | Removal of the Electronic Engine Control (EEC) Wiring Harness (W03) |
| AMM 73-21-63-400-802 | Installation of the Electronic Engine Control (EEC) Wiring Harness (W03) |
| AMM 73-21-64-000-802 | Removal of the Electronic Engine Control (EEC) Wiring Harness (W04) |
| AMM 73-21-64-400-802 | Installation of the Electronic Engine Control (EEC) Wiring Harness (W04) |
| AMM 73-21-70-000-802 | Removal of the Electronic Engine Control (EEC) Wiring Harness (WC11) |
| AMM 73-21-70-400-802 | Installation of the Electronic Engine Control (EEC) Wiring Harness (WC11) |
| 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 73-13-00-710-052-A ** ON A/C NOT FOR ALL
A. Not Applicable
(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) is reporting the fuel Return To Tank (RTT) valve has failed in the open position in channel A and channel B. The fuel RTT valve is located under the fuel/oil heat exchanger bypass valve at the 5 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 73-13-00-810-052-A ** ON A/C NOT FOR ALL A. Do as follows:
(1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Replace FUEL RETURN TO TANK MODULE [4082KS] AMM 73-13-03-000-801 and AMM 73-13-03-400-801.
(a) Do the test given in Para. 4.B.
(3) If the fault continues:
(a) Examine the W04 (4088KS), W03 (4087KS) and WC11 (4072KS) harnesses and connectors P3 (4000KS-P3) and P4 (4000KS-P4) - EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS- P68) - Fuel RTT valve (4082KS), for problems which are possible between the EEC (4000KS) and the fuel RTT valve (4082KS).
1 Inspect for harness damage.
2 Inspect for loose or damaged connectors.
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
3 Replace HARNESS-CORE,WC11 [4072KS] AMM 73-21-70-000-802 and AMM 73-21-70-400-802.
4 Do the test given in Para. 4.B.
(4) If no problems are found with the harnesses or the fault continues, use a PLIERS - JAWED, SOFT to disconnect electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) - EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS- P68) from the fuel RTT valve (4082KS).
(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 the connector face AMM 70-70-00-910-803.
(c) Reconnect electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) to the EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS- P68) to the fuel RTT valve (4082KS).
(d) Do the test given in Para. 4.B.
(5) If the fault continues:
(a) Disconnect electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS-P68) from the fuel RTT valve (4082KS). Use a MULTIMETER - STANDARD to test the fuel RTT valve (4082KS) solenoid circuits in the harnesses. Refer to Table 1, Table 2, Table 3 and Table 4. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).
Table 2: Fuel Return To Tank Valve Proximity Sensor Channel A Connector Contacts
Table 3: Fuel Return To Tank Valve Solenoid Channel B Connector Contacts
Table 4: Fuel Return To Tank Valve Proximity Sensor Channel B Connector Contacts
(b) If a problem is found with the harnesses or connectors:
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
3 Replace HARNESS-CORE,WC11 [4072KS] AMM 73-21-70-000-802 and AMM 73-21-70-400-802.
4 Do the test given in Para. 4.B.
(6) If no problems are found with the harnesses or the fault continues:
(a) Replace the
(b) Do the test given in Para. 4.B.
Subtask 73-13-00-710-063-A ** ON A/C NOT FOR ALL (1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Replace FUEL RETURN TO TANK MODULE [4082KS] AMM 73-13-03-000-801 and AMM 73-13-03-400-801.
(a) Do the test given in Para. 4.B.
(3) If the fault continues:
(a) Examine the W04 (4088KS), W03 (4087KS) and WC11 (4072KS) harnesses and connectors P3 (4000KS-P3) and P4 (4000KS-P4) - EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS- P68) - Fuel RTT valve (4082KS), for problems which are possible between the EEC (4000KS) and the fuel RTT valve (4082KS).
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.
(b) If a problem is found with the harness or connectors: 1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
3 Replace HARNESS-CORE,WC11 [4072KS] AMM 73-21-70-000-802 and AMM 73-21-70-400-802.
4 Do the test given in Para. 4.B.
(4) If no problems are found with the harnesses or the fault continues, use a PLIERS - JAWED, SOFT to disconnect electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) - EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS- P68) from the fuel RTT valve (4082KS).
(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 the connector face AMM 70-70-00-910-803.
(c) Reconnect electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) to the EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS- P68) to the fuel RTT valve (4082KS).
(d) Do the test given in Para. 4.B.
(5) If the fault continues:
(a) Disconnect electrical connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS), interconnect J105 (4108VC)/P105 (4108VC-A), interconnect P106 (4100VC-A)/J106 (4100VC) and connector P68 (4082KS-P68) from the fuel RTT valve (4082KS). Use a MULTIMETER - STANDARD to test the fuel RTT valve (4082KS) solenoid circuits in the harnesses. Refer to Table 1, Table 2, Table 3 and Table 4. 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: Fuel Return To Tank Valve Solenoid Channel A Connector Contacts | W04 (4088KS) Harness P3 (4000KS-P3) EEC (4000KS) Connector Contacts | W04 (4088KS) Harness J105 (4108VC) Connector Contacts | WC11 (4072KS) Harness P105 (4108VC-A) Connector Contacts | WC11 (4072KS) Harness P68 (4082KS-P68) Fuel RTT Valve (4082KS) Connector Contacts |
|---|---|---|---|
| L | 11 | 11 | 12 |
| k | 12 | 12 | 13 |
Table 2: Fuel Return To Tank Valve Proximity Sensor Channel A Connector Contacts
| W04 (4088KS) Harness P3 (4000KS-P3) EEC (4000KS) Connector Contacts | W04 (4088KS) Harness J105 (4108VC) Connector Contacts | WC11 (4072KS) Harness P105 (4108VC-A) Connector Contacts | WC11 (4072KS) Harness P68 (4082KS-P68) Fuel RTT Valve (4082KS) Connector Contacts |
|---|---|---|---|
| AA | 23 | 23 | 4 |
| i | 24 | 24 | 14 |
| K | 25 | 25 | 5 |
| J | 26 | 26 | 15 |
Table 3: Fuel Return To Tank Valve Solenoid Channel B Connector Contacts
| W03(4087KS) Harness P4 (4000KS-P4) EEC(4000KS) Connector Contacts | W03(4087KS) Harness P106 (4100VC-A) Connector Contacts | W04(4088KS) Harness J106 (4100VC) Connector Contacts | W04(4088KS) Harness J105 (4108VC) Connector Contacts | WC11(4072KS) Harness P105 (4108VC-A) Connector Contacts | WC11(4072KS) Harness P68 (4082KS-P68) Fuel RTT Valve(4082KS) Connector Contacts |
|---|---|---|---|---|---|
| L | 44 | 44 | 17 | 17 | 9 |
| k | 45 | 45 | 18 | 18 | 20 |
Table 4: Fuel Return To Tank Valve Proximity Sensor Channel B Connector Contacts
| W03(4087KS) Harness P4 (4000KS-P4) EEC(4000KS) Connector Contacts | W03(4087KS) Harness P106 (4100VC-A) Connector Contacts | W04(4088KS) Harness J106 (4100VC) Connector Contacts | W04(4088KS) Harness J105 (4108VC) Connector Contacts | WC11(4072KS) Harness P105 (4108VC-A) Connector Contacts | WC11(4072KS) Harness P68 (4082KS-P68) Fuel RTT Valve(4082KS) Connector Contacts |
|---|---|---|---|---|---|
| AA | 46 | 46 | 19 | 19 | 8 |
| i | 47 | 47 | 20 | 20 | 19 |
| K | 48 | 48 | 21 | 21 | 7 |
| J | 49 | 49 | 22 | 22 | 18 |
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
3 Replace HARNESS-CORE,WC11 [4072KS] AMM 73-21-70-000-802 and AMM 73-21-70-400-802.
4 Do the test given in Para. 4.B.
(6) If no problems are found with the harnesses or the fault continues:
(a) Replace the
(b) Do the test given in Para. 4.B.
B. Repair Confirmation
(1) Do an engine wet-motoring to confirm repair of this fault AMM 71-00-00-860-825.
(2) Stop the engine wet-motoring.
(3) On MCDU screen, check if the fault is displayed on ground scanning report.
5. Close-up(1) Do an engine wet-motoring to confirm repair of this fault AMM 71-00-00-860-825.
(2) Stop the engine wet-motoring.
(3) On MCDU screen, check if the fault is displayed on ground scanning report.
Subtask 73-13-00-860-052-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.