DOC AIRBUS | TSM A320FInhibition Proximity Switch Disagreement Failure
TASK 78-31-00-810-942-A
Inhibition Proximity Switch Disagreement Failure
1. Possible Causes
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 78-31-00-710-258-A ** ON A/C NOT FOR ALL
Subtask 78-31-00-860-052-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:38:11 UTC
Inhibition Proximity Switch Disagreement Failure
1. Possible Causes
- HCU-T/R, ENG1 [4310EG1]
- HCU-T/R, ENG2 [4310EG2]
- HARNESS-FAN, WF02 [4218KS]
- HARNESS-FAN, WF01 [4217KS]
- HCU PROXI SENSOR ENG 1A [100EG1]
- HCU PROXI SENSOR ENG 2A [100EG2]
- HCU PROXI SENSOR ENG 1B [101EG1]
- HCU PROXI SENSOR ENG 2B [101EG2]
[4000KS]
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | PLIERS - JAWED, SOFT |
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 71-00-00-810-843-A | Nacelle Component and Harness Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults |
| AMM 71-13-00-010-802 | Opening of the Fan Cowl Doors |
| AMM 71-13-00-410-802 | Closing of the Fan Cowl Doors |
| AWM 715135 | |
| 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 73-21-61-000-802 | Removal of the Electronic Engine Control (EEC) Wiring Harness (WF01) |
| AMM 73-21-61-400-802 | Installation of the Electronic Engine Control (EEC) Wiring Harness (WF01) |
| 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) |
| AMM 78-31-00-210-802 | General Visual Inspection (GVI) of the Proximity Sensor Targets |
| AMM 78-31-00-710-805 | Operational Test of Thrust Reverser with MCDU |
| AMM 78-31-01-000-801 | Removal of the TRAS Hydraulic Control Unit (HCU) |
| AMM 78-31-01-400-801 | Installation of the TRAS Hydraulic Control Unit (HCU) |
| AMM 78-31-22-000-801 | Removal of the Hydraulic Control Unit (HCU) Proximity Sensor |
| AMM 78-31-22-400-801 | Installation of the Hydraulic Control Unit (HCU) Proximity Sensor |
| FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1) | |
| AWM 783611 | |
| FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2) | |
| AWM 783612 | |
Subtask 78-31-00-710-258-A ** ON A/C NOT FOR ALL
A. Do the operational test of the thrust reverser with the MCDU to confirm this fault. Refer to AMM 78-31-00-710-805.
(1) If the maintenance message does not come back, troubleshoot as described in the nacelle component and harness troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-843).
(a) Monitor the engine reoccurring maintenance message.
(2) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
4. Fault Isolation(1) If the maintenance message does not come back, troubleshoot as described in the nacelle component and harness troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-843).
(a) Monitor the engine 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.
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 78-31-00-810-287-A ** ON A/C NOT FOR ALL A. If there is confirmation of the fault:
(1) Get access to the HCU, EEC and pylon junction box.
(a) Remove the access panel from the pylon to get access to the HCU:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AL
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AL
(b) Open the fan cowl doors AMM 71-13-00-010-802.
(2) At switches (100EG) and (101EG), make sure that the target is not missing and do a visual inspection of the target for bend, breakage, or other damage AMM 78-31-00-210-802.
(a) If you find a bend, breakage or other damage, or if the target is missing:
1 Replace HCU-T/R, ENG1 [4310EG1] or HCU-T/R, ENG2 [4310EG2] AMM 78-31-01-000-801 and AMM 78-31-01-400-801.
2 Do the test given in Para. 3.
(3) If you find no damage or if the fault continues:
(a) Check for the correct engagement of connector (100EG-A) with proximity sensor (100EG) and connector (101EG-A) with proximity sensor (101EG).
1 Repair as necessary.
2 Do the test given in Para. 3.
(4) If check is OK or if the fault continues, use a PLIERS - JAWED, SOFT to disconnect connector (100EG-A) from the proximity sensor (100EG) and the connector (101EG-A) from the proximity sensor (101EG).
(a) Do a visual inspection of the connector for bent pins, contamination or corrosion or other signs of damage.
(b) If you find damage, replace the pylon harness:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(c) Reconnect the connector (100EG-A) to the proximity sensor (100EG) and the connector (101EG-A) to the proximity sensor (101EG).
(d) Do the test given in Para. 3.
(5) If you find no damage or if the fault continues, disconnect connectors (100EG-A), (101EG-A) ,P1 and P2 from EEC (4000KS) AWM 715135.
(a) Do a continuity check (less than 5 ohms) between the pins of connectors P1 and (100EG-A) and between the pins of connectors P2 and (101EG-A) as follows:
(c) Do a continuity check (less than 5 ohms) between the pins of connectors P1 and (P402) and between the pins of connectors P2 and (P403) as follow:
(e) If you find a fault:
1 Replace HARNESS-FAN, WF02 [4218KS] AMM 73-21-62-000-802 and AMM 73-21-62-400-802, or
2 Replace HARNESS-FAN, WF01 [4217KS] AMM 73-21-61-000-802 and AMM 73-21-61-400-802.
3 Do the test given in Para. 3.
(f) If there is continuity:
1 Replace pylon harness:
a FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
2 Reconnect all connectors.
3 Do the test given in Para. 3.
(6) If you find no damage or if the fault continues:
(a) Replace HCU PROXI SENSOR ENG 1A [100EG1] or HCU PROXI SENSOR ENG 2A [100EG2] or HCU PROXI SENSOR ENG 1B [101EG1] or HCU PROXI SENSOR ENG 2B [101EG2] AMM 78-31-22-000-801 and AMM 78-31-22-400-801.
(b) Do the test given in Para. 3.
(7) If you find no fault or if the fault continues, replace
(a) Do the test given in Para. 3.
5. Close-up(1) Get access to the HCU, EEC and pylon junction box.
(a) Remove the access panel from the pylon to get access to the HCU:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AL
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AL
(b) Open the fan cowl doors AMM 71-13-00-010-802.
(2) At switches (100EG) and (101EG), make sure that the target is not missing and do a visual inspection of the target for bend, breakage, or other damage AMM 78-31-00-210-802.
(a) If you find a bend, breakage or other damage, or if the target is missing:
1 Replace HCU-T/R, ENG1 [4310EG1] or HCU-T/R, ENG2 [4310EG2] AMM 78-31-01-000-801 and AMM 78-31-01-400-801.
2 Do the test given in Para. 3.
(3) If you find no damage or if the fault continues:
(a) Check for the correct engagement of connector (100EG-A) with proximity sensor (100EG) and connector (101EG-A) with proximity sensor (101EG).
1 Repair as necessary.
2 Do the test given in Para. 3.
(4) If check is OK or if the fault continues, use a PLIERS - JAWED, SOFT to disconnect connector (100EG-A) from the proximity sensor (100EG) and the connector (101EG-A) from the proximity sensor (101EG).
(a) Do a visual inspection of the connector for bent pins, contamination or corrosion or other signs of damage.
(b) If you find damage, replace the pylon harness:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(c) Reconnect the connector (100EG-A) to the proximity sensor (100EG) and the connector (101EG-A) to the proximity sensor (101EG).
(d) Do the test given in Para. 3.
(5) If you find no damage or if the fault continues, disconnect connectors (100EG-A), (101EG-A) ,P1 and P2 from EEC (4000KS) AWM 715135.
(a) Do a continuity check (less than 5 ohms) between the pins of connectors P1 and (100EG-A) and between the pins of connectors P2 and (101EG-A) as follows:
- Pin N and pin 2
- Pin k and pin 5
- Pin m and pin 3.
(c) Do a continuity check (less than 5 ohms) between the pins of connectors P1 and (P402) and between the pins of connectors P2 and (P403) as follow:
- Pin N and pin 7
- Pin k and pin 8
- Pin m and pin 9.
(e) If you find a fault:
1 Replace HARNESS-FAN, WF02 [4218KS] AMM 73-21-62-000-802 and AMM 73-21-62-400-802, or
2 Replace HARNESS-FAN, WF01 [4217KS] AMM 73-21-61-000-802 and AMM 73-21-61-400-802.
3 Do the test given in Para. 3.
(f) If there is continuity:
1 Replace pylon harness:
a FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
2 Reconnect all connectors.
3 Do the test given in Para. 3.
(6) If you find no damage or if the fault continues:
(a) Replace HCU PROXI SENSOR ENG 1A [100EG1] or HCU PROXI SENSOR ENG 2A [100EG2] or HCU PROXI SENSOR ENG 1B [101EG1] or HCU PROXI SENSOR ENG 2B [101EG2] AMM 78-31-22-000-801 and AMM 78-31-22-400-801.
(b) Do the test given in Para. 3.
(7) If you find no fault or if the fault continues, replace
(a) Do the test given in Para. 3.
Subtask 78-31-00-860-052-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 fan cowl doors AMM 71-13-00-410-802.
(b) Close the pylon access panel:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AL
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AL
(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.
(b) Close the pylon access panel:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AL
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AL