DOC AIRBUS | TSM A320FACC/Actuator Null Shift channel B
TASK 75-24-00-810-825-A
ACC/Actuator Null Shift channel B
1. Possible Causes
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 75-24-00-710-104-A ** ON A/C NOT FOR ALL
Subtask 75-24-00-860-063-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:37:14 UTC
ACC/Actuator Null Shift channel B
1. Possible Causes
- TURBINE ACC AIR VALVE [4055KS]
- W03 HARNESS [4087KS]
- W04 HARNESS [4088KS]
- WC08 HARNESS-CORE [4094KS]
[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 73-21-00-710-809 | Test No.15 - Operation Test (Dry Motor) of the FADEC System Engine Actuators |
| 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 73-21-68-000-802 | Removal of the EEC Wiring Harness (WC08) |
| AMM 73-21-68-400-802 | Installation of the EEC Wiring Harness (WC08) |
| AMM 75-24-01-000-801 | Removal of the Turbine Active Clearance Control (ACC) Air Valve |
| AMM 75-24-01-400-801 | Installation of the Turbine Active Clearance Control (ACC) Air Valve |
| 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 75-24-00-710-104-A ** ON A/C NOT FOR ALL
A. Do the FADEC system actuator test to confirm this fault. Refer to FADEC system actuator test AMM 73-21-00-710-809.
(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 the Turbine (TURB) Active Clearance Control (ACC) air valve Torque Motor (TM) requires more current to stay in position in channel B. This fault is usually an indication of a problem with the actuator TM or internal servo valve. The turbine ACC air valve is mounted on the High Pressure Compressor (HPC), located at the 12 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 75-24-00-810-088-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 TURBINE ACC AIR VALVE [4055KS] AMM 75-24-01-000-801 and AMM 75-24-01-400-801.
(a) Do the test given in Para. 3.
(3) If the fault continues:
(a) Examine the W03 (4087KS), W04 (4088KS) and WC08 (4094KS) harnesses, connector P6 (4000KS-P6) - EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) - Turbine ACC air valve (4055KS), for problems which are possible between the EEC (4000KS) and the turbine ACC air valve (4055KS).
1 Inspect for harness damage.
2 Inspect for loose or damaged connectors.
1 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
3 Replace WC08 HARNESS-CORE [4094KS] AMM 73-21-68-000-802 and AMM 73-21-68-400-802.
4 Do the test given in Para. 3.
(4) If no problems are found with the harnesses, use a PLIERS - JAWED, SOFT to disconnect electrical connector P6 (4000KS-P6) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) from the turbine ACC air valve (4055KS).
(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 connector P6 (4000KS-P6) to the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) to the turbine ACC air valve (4055KS).
(d) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect electrical connector P6 (4000KS-P6) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) from the turbine ACC air valve (4055KS). Use a MULTIMETER - STANDARD to test the turbine ACC air valve (4055KS) TM circuits in the harnesses. 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 harnesses or connectors:
1 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
3 Replace WC08 HARNESS-CORE [4094KS] AMM 73-21-68-000-802 and AMM 73-21-68-400-802.
4 Do the test given in Para. 3.
(6) If the fault continues:
(a) Replace the
(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 TURBINE ACC AIR VALVE [4055KS] AMM 75-24-01-000-801 and AMM 75-24-01-400-801.
(a) Do the test given in Para. 3.
(3) If the fault continues:
(a) Examine the W03 (4087KS), W04 (4088KS) and WC08 (4094KS) harnesses, connector P6 (4000KS-P6) - EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) - Turbine ACC air valve (4055KS), for problems which are possible between the EEC (4000KS) and the turbine ACC air valve (4055KS).
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 harnesses or connectors: 1 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
3 Replace WC08 HARNESS-CORE [4094KS] AMM 73-21-68-000-802 and AMM 73-21-68-400-802.
4 Do the test given in Para. 3.
(4) If no problems are found with the harnesses, use a PLIERS - JAWED, SOFT to disconnect electrical connector P6 (4000KS-P6) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) from the turbine ACC air valve (4055KS).
(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 connector P6 (4000KS-P6) to the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) to the turbine ACC air valve (4055KS).
(d) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect electrical connector P6 (4000KS-P6) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC), interconnect J109 (4112VC)/P109 (4112VC-A) and connector P31 (4055KS-P31) from the turbine ACC air valve (4055KS). Use a MULTIMETER - STANDARD to test the turbine ACC air valve (4055KS) TM circuits in the harnesses. 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: Turbine ACC Air Valve TM Channel B Connector Contacts | W03(4087KS) Harness P6 (4000KS-P6) EEC(4000KS) Connector Contacts | W03(4087KS) Harness P107 (4101VC-A) Connector Contacts | W04(4088KS) Harness J107 (4101VC) Connector Contacts | W04(4088KS) Harness J109 (4112VC) Connector Contacts | WC08(4094KS) Harness P109 (4112VC-A) Connector Contacts | WC08(4094KS) Harness P31 (4055KS-P31) TURB ACC air valve(4055KS) Connector Contacts |
|---|---|---|---|---|---|
| v | 8 | 8 | 4 | 4 | 11 |
| c | 9 | 9 | 5 | 5 | 3 |
1 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802, or
2 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
3 Replace WC08 HARNESS-CORE [4094KS] AMM 73-21-68-000-802 and AMM 73-21-68-400-802.
4 Do the test given in Para. 3.
(6) If the fault continues:
(a) Replace the
(b) Do the test given in Para. 3.
Subtask 75-24-00-860-063-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.