DOC AIRBUS | TSM A320FBuffer Air Pressure Sensor Electrical Failure Channel B
TASK 75-26-00-810-821-A
Buffer Air Pressure Sensor Electrical Failure Channel B
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 75-26-00-710-088-A ** ON A/C NOT FOR ALL
Subtask 75-26-00-860-056-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:37:19 UTC
Buffer Air Pressure Sensor Electrical Failure Channel B
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 73-21-63-000-802 | 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 75-26-22-000-801 | Removal of the Buffer Air Valve Pressure Sensor |
| AMM 75-26-22-400-801 | Installation of the Buffer Air Valve Pressure Sensor |
| 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 75-26-00-710-088-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 channe B, go to the Para. Fault Isolation.
4. Fault IsolationNOTE: The Electronic Engine Control (EEC) has detected that the buffer air valve pressure sensor circuit is out of range or rate in channel B. The buffer air valve pressure sensor is attached to the compressor intermediate case bulkhead located at the 3 o'clock position.
(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 channe B, 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 75-26-00-810-070-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) Examine the W03 (4087KS) and W04 (4088KS) harnesses, connector P14 (4000KS-P14) - EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connector P69 (4057KS-P69) - buffer air valve pressure sensor (4057KS), for problems which are possible between the EEC (4000KS) and the buffer air valve pressure sensor (4057KS).
(a) Inspect for harness damage.
(b) 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.
3 Do the test given in Para. 3.
(3) If no problems are found with the harnesses or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P14 (4000KS-P14) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connector P69 (4057KS-P69) from the buffer air valve pressure sensor (4057KS).
(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 the electrical connector P14 (4000KS-P14) to the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connector P69 (4057KS-P69) to the buffer air valve pressure sensor (4057KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace BUFFER AIR VALVE PRESSURE SENSOR [4057KS] AMM 75-26-22-000-801 and AMM 75-26-22-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P14 (4000KS-P14) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connectors P69 (4057KS-P69) from the buffer air valve pressure sensor (4057KS). Use a MULTIMETER - STANDARD to test the buffer air valve pressure sensor (4057KS) channel B 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.
3 Do the test given in Para. 3.
(6) If no problems are found with the harnesses or 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) Examine the W03 (4087KS) and W04 (4088KS) harnesses, connector P14 (4000KS-P14) - EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connector P69 (4057KS-P69) - buffer air valve pressure sensor (4057KS), for problems which are possible between the EEC (4000KS) and the buffer air valve pressure sensor (4057KS).
(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 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.
3 Do the test given in Para. 3.
(3) If no problems are found with the harnesses or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P14 (4000KS-P14) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connector P69 (4057KS-P69) from the buffer air valve pressure sensor (4057KS).
(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 the electrical connector P14 (4000KS-P14) to the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connector P69 (4057KS-P69) to the buffer air valve pressure sensor (4057KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace BUFFER AIR VALVE PRESSURE SENSOR [4057KS] AMM 75-26-22-000-801 and AMM 75-26-22-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P14 (4000KS-P14) from the EEC (4000KS), interconnect P107 (4101VC-A)/J107 (4101VC) and connectors P69 (4057KS-P69) from the buffer air valve pressure sensor (4057KS). Use a MULTIMETER - STANDARD to test the buffer air valve pressure sensor (4057KS) channel B 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: Buffer Air Valve Pressure Sensor Channel B Connector Contacts | W03 (4087KS) Harness P14 (4000KS-P14) EEC(4000KS) Connector Contacts | W03 (4087KS) Harness P107 (4101VC-A) Connector Contacts | W04 (4088KS) Harness J107 (4101VC) Connector Contacts | W04 (4088KS) Harness P69 (4057KS-P69) Buffer Air Valve Pressure Sensor (4057KS) Connector Contacts |
|---|---|---|---|
| DD | 48 | 48 | 9 |
| U | 49 | 49 | 8 |
| CC | 50 | 50 | 7 |
| S | 51 | 51 | 6 |
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.
3 Do the test given in Para. 3.
(6) If no problems are found with the harnesses or the fault continues:
(a) Replace
(b) Do the test given in Para. 3.
Subtask 75-26-00-860-056-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.