DOC AIRBUS | TSM A320FN1 Sensor Signal Disagreement
TASK 77-11-00-810-813-A
N1 Sensor Signal Disagreement
1. Possible Causes
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 77-11-00-710-063-A ** ON A/C NOT FOR ALL
Subtask 77-11-00-860-055-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:37:55 UTC
N1 Sensor Signal Disagreement
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 73-21-63-000-802 | 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 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 77-11-00-710-063-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, check if the fault is displayed on ground scanning 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 Confirmation.
4. Fault Isolation(1) Shutdown the engine AMM 71-00-00-860-814.
(2) On MCDU screen, check if the fault is displayed on ground scanning report.
NOTE: The Electronic Engine Control (EEC) has detected that the circuits for the N1 speed probe do not agree between channels A and B. The N1 speed probe is mounted on the compressor intermediate case, located at the 3 o'clock position.
(3) 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 for 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 Confirmation.
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 77-11-00-810-065-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) and W03 (4087KS) harnesses and connectors P3 (4000KS-P3) and P4 (4000KS-P4) - EEC (4000KS) and connector P47 (4064KS-P47) and P48 (4064KS-P48) - N1 speed probe (4064KS), for problems between the EEC (4000KS) and the N1 speed probe (4064KS).
(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 connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS) and connectors P47 (4064KS-P47) and P48 (4064KS-P48) 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 the 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 connectors P3 (4000KS-P3) and P4 (4000KS-P4) to the EEC(4000KS) and connectors P47 (4064KS-P47) and P48 (4064KS-P48) 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 connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS) and connectors P47 (4064KS-P47) and P48 (4064KS-P48) from the N1 speed probe (4064KS). Use a MULTIMETER - STANDARD to test the N1 speed probe (4064KS) channel A and B circuits in the harnesses. Refer to Table 1 and Table 2. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).
Table 2: N1 Speed Probe Channel B Circuit Connector Contacts
(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 W04 (4088KS) and W03 (4087KS) harnesses and connectors P3 (4000KS-P3) and P4 (4000KS-P4) - EEC (4000KS) and connector P47 (4064KS-P47) and P48 (4064KS-P48) - N1 speed probe (4064KS), for problems 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 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 connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS) and connectors P47 (4064KS-P47) and P48 (4064KS-P48) 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 the 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 connectors P3 (4000KS-P3) and P4 (4000KS-P4) to the EEC(4000KS) and connectors P47 (4064KS-P47) and P48 (4064KS-P48) 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 connectors P3 (4000KS-P3) and P4 (4000KS-P4) from the EEC (4000KS) and connectors P47 (4064KS-P47) and P48 (4064KS-P48) from the N1 speed probe (4064KS). Use a MULTIMETER - STANDARD to test the N1 speed probe (4064KS) channel A and B circuits in the harnesses. Refer to Table 1 and Table 2. 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 |
| W03 (4087KS) Harness P4 (4000KS-P4) EEC (4000KS) Connector Contacts | W03 (4087KS) Harness P48 (4064KS-P48) N1 Speed Probe (4064KS) Connector Contacts |
|---|---|
| X | 4 |
| W | 5 |
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 77-11-00-860-055-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.