DOC AIRBUS | TSM A320FN1 Sensor Electrical Failure Channel A
TASK 77-11-00-810-809-A
N1 Sensor Electrical 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 77-11-00-710-058-A ** ON A/C NOT FOR ALL
Subtask 77-11-00-860-051-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:40:45 UTC
N1 Sensor Electrical 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 71-00-00-860-814 | Shutdown of the Engine |
| AMM 71-00-00-860-822 | Start the Engine (Normal Manual Start) |
| AMM 71-00-00-860-823 | Start the Engine (Normal Automatic Start) |
| 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 73-21-64-000-802 | 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 77-11-21-000-801 | Removal of the N1 Speed Probe |
| AMM 77-11-21-400-801 | Installation of the N1 Speed Probe |
| 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 77-11-00-710-058-A ** ON A/C NOT FOR ALL
A. Do an engine run to idle to confirm repair of this fault AMM 71-00-00-860-822 or AMM 71-00-00-860-823.
(1) Shutdown the engine AMM 71-00-00-860-814.
(2) On MCDU screen, make sure that the fault is not displayed on ground scan report.
(a) If no problems are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(4) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
4. Fault Isolation(1) Shutdown the engine AMM 71-00-00-860-814.
(2) On MCDU screen, make sure that the fault is not displayed on ground scan report.
NOTE: The Electronic Engine Control (EEC) has detected the circuit for the N1 speed probe is out of range or rate in channel A. The N1 speed probe is mounted on the compressor intermediate case, located at the 3 o'clock position.
(3) If 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.
(4) 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 77-11-00-810-061-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 W04 (4088KS) harness, connector P3 (4000KS-P3) - EEC (4000KS) and P47 (4064KS-P47) - N1 speed probe (4064KS), for problems which are possible between the EEC (4000KS) and the N1 speed probe (4064KS).
(a) Inspect for harness damage.
(b) Inspect for loose or damaged connectors.
1 Replace W04 HARNESS(4088KS) AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(3) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P3 (4000KS-P3) from the EEC (4000KS) and connector P47 (4064KS-P47) from the N1 speed probe (4064KS).
(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 P3 (4000KS-P3) to the EEC (4000KS) and Connector P47 (4064KS-P47) to the N1 speed probe (4064KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace PROBE-N1 [4064KS] AMM 77-11-21-000-801 and AMM 77-11-21-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P3 (4000KS-P3) from the EEC (4000KS) and connector P47 (4064KS-P47) from the N1 speed probe (4064KS). Use a MULTIMETER - STANDARD to test the N1 speed probe (4064KS) channel A circuit 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 W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(6) If no problems are found with the harness or 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) Examine the W04 (4088KS) harness, connector P3 (4000KS-P3) - EEC (4000KS) and P47 (4064KS-P47) - N1 speed probe (4064KS), for problems which are possible between the EEC (4000KS) and the N1 speed probe (4064KS).
(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 harness or connectors: 1 Replace W04 HARNESS(4088KS) AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(3) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P3 (4000KS-P3) from the EEC (4000KS) and connector P47 (4064KS-P47) from the N1 speed probe (4064KS).
(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 P3 (4000KS-P3) to the EEC (4000KS) and Connector P47 (4064KS-P47) to the N1 speed probe (4064KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace PROBE-N1 [4064KS] AMM 77-11-21-000-801 and AMM 77-11-21-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P3 (4000KS-P3) from the EEC (4000KS) and connector P47 (4064KS-P47) from the N1 speed probe (4064KS). Use a MULTIMETER - STANDARD to test the N1 speed probe (4064KS) channel A circuit 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: N1 Speed Probe Channel A Circuit Connector Contacts | W04 (4088KS) Harness P3 (4000KS-P3) EEC (4000KS) Connector Contacts | W04 (4088KS) Harness P47 (4064KS-P47) N1 Speed Probe (4064KS) Connector Contacts |
|---|---|
| X | 4 |
| W | 5 |
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(6) If no problems are found with the harness or the fault continues:
(a) Replace the
(b) Do the test given in Para. 3.
Subtask 77-11-00-860-051-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.