W DOC AIRBUS | TSM A320F

Loss of N2 Feedback Signal - Engine 2 - Channel A and Channel B

TASK 77-10-00-810-820-A
Loss of N2 Feedback Signal - Engine 2 - Channel A and Channel B

1. Possible Causes
  • SENSOR-N2 ROTATIONAL SPD [4001EV]
  • ECU [4000KS]
  • J7 harness
  • J8 harness
  • HJ7 harness
  • HJ8 harness
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
BRUSH - BRISTLED
 B. Consumable Materials
REFERENCE
DESIGNATION
(Material No.CP2011)
stoddard solvent
 C. Referenced Information
REFERENCE
DESIGNATION
AMM 73-21-50-000-006
Removal of J7 Harness
AMM 73-21-50-000-007
Removal of J8 Harness
AMM 73-21-50-000-040
Removal of the HJ7 Harness for SAC Engines
AMM 73-21-50-000-041
Removal of the HJ8 Harness for SAC Engines
AMM 73-21-50-210-001
Visual Inspection of the Wiring Harness
AMM 73-21-50-210-002
Visual Inspection of the Wiring Harnesses
AMM 73-21-50-400-006
Installation of the J7 Harness
AMM 73-21-50-400-007
Installation of the J8 Harness
AMM 73-21-50-400-040
Installation of the HJ7 Harness for SAC Engines
AMM 73-21-50-400-041
Installation of the HJ8 Harness for SAC Engines
AMM 73-21-60-000-001
Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001
Installation of the Electronic Control Unit (ECU)
AMM 73-29-00-710-040
Operational Test of the FADEC on the ground (with Engine Motoring)
AMM 77-11-20-000-001
Removal of the N2 Speed Sensor
AMM 77-11-20-000-002
Removal of the N2 Speed Sensor .
AMM 77-11-20-400-001
Installation of the N2 Speed Sensor
AMM 77-11-20-400-002
Installation of the N2 Speed Sensor .
3. Fault Confirmation
Subtask 77-10-00-710-088-A ** ON A/C NOT FOR ALL
A. Do the operational test of the FADEC 2A and 2B on the ground (with engine non motoring) AMM 73-29-00-710-040.
4. Fault Isolation
Subtask 77-10-00-810-069-A ** ON A/C NOT FOR ALL
A. The failure message is generated if both channel A and channel B signals are invalid or out of range.
   (1) If the failure messages N2 SENS, J7, ECU and N2 SENS, J8, ECU are not confirmed:
     (a) No maintenance action is required.
   (2) If the failure messages N2 SENS, J7, ECU and N2 SENS, J8, ECU are not confirmed but are repetitive:
  • disconnect J7 harness from the N2 sensor (N2-A connector) and disconnect J8 harness from the N2 sensor (N2-B connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do a cleaning of the connectors and receptacles using a BRUSH - BRISTLED with stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
     (b) If the failure continues during the subsequent flights:
     (c) If the failure continues during the subsequent flights:
     (d) If the failure continues during the subsequent flights:
     (e) If the failure continues during the subsequent flights:
   (3) If the failure message N2 SENS, J7, ECU is confirmed:
  • disconnect the J7 harness from the N2 sensor (N2-A connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the N2 sensor (4001EV) (channel A) between:
    . pins 1 and 2 (40 to 80 ohms)
    . pins 1 and 3 (>10 megohms)
    . pin 1 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • connect the J7 harness to the N2 sensor.
     (b) Disconnect connector J7 from the ECU (4000KS) receptacle and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the J7 harness between:
    . pins 2 and 11 (40 to 80 ohms)
    . pins 2 and 3 (>10 megohms)
    . pin 2 and the ground (>10 megohms).
         a If the resistance values are in the specified limits:
         b If the resistance values are out of the specified limits:
   (4) If the failure message N2 SENS, J8, ECU is confirmed:
  • disconnect the J8 harness from the N2 sensor (N2-B connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the N2 sensor (4001EV) (channel B) between:
    . pins 1 and 2 (40 to 80 ohms)
    . pins 1 and 3 (>10 megohms)
    . pin 1 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • connect the J8 harness to the N2 sensor.
     (b) Disconnect connector J8 from the ECU (4000KS) receptacle and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the J8 harness between:
    . pins 2 and 11 (40 to 80 ohms)
    . pins 2 and 3 (>10 megohms)
    . pin 2 and the ground (>10 megohms).
         a If the resistance values are in the specified limits:
         b If the resistance values are out of the specified limits:
Subtask 77-10-00-810-069-B ** ON A/C NOT FOR ALL
A. The failure message is generated if both channel A and channel B signals are invalid or out of range.
   (1) If the failure messages N2 SNSR, J7, ECU and N2 SNSR, J8, ECU are not confirmed:
     (a) No maintenance action is required.
   (2) If the failure messages N2 SNSR, J7, ECU and N2 SNSR, J8, ECU are not confirmed but are repetitive:
  • disconnect J7 harness from the N2 sensor (N2-A connector) and disconnect J8 harness from the N2 sensor (N2-B connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do a cleaning of the connectors and receptacles using a BRUSH - BRISTLED with stoddard solvent (Material No.CP2011) AMM 73-21-50-210-001.
     (b) If the failure continues during the subsequent flights:
     (c) If the failure continues during the subsequent flights:
     (d) If the failure continues during the subsequent flights:
     (e) If the failure continues during the subsequent flights:
   (3) If the failure message N2 SNSR, J7, ECU is confirmed:
  • disconnect the J7 harness from the N2 sensor (N2-A connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the N2 sensor (4001EV) (channel A) between:
    . pins 1 and 2 (40 to 80 ohms)
    . pins 1 and 3 (>10 megohms)
    . pin 1 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • connect the J7 harness to the N2 sensor.
     (b) Disconnect connector J7 from the ECU (4000KS) receptacle and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the J7 harness between:
    . pins 2 and 11 (40 to 80 ohms)
    . pins 2 and 3 (>10 megohms)
    . pin 2 and the ground (>10 megohms).
         a If the resistance values are in the specified limits:
         b If the resistance values are out of the specified limits:
   (4) If the failure message N2 SNSR, J8, ECU is confirmed:
  • disconnect the J8 harness from the N2 sensor (N2-B connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the N2 sensor (4001EV) (channel B) between:
    . pins 1 and 2 (40 to 80 ohms)
    . pins 1 and 3 (>10 megohms)
    . pin 1 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • connect the J8 harness to the N2 sensor.
     (b) Disconnect connector J8 from the ECU (4000KS) receptacle and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-001.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the J8 harness between:
    . pins 2 and 11 (40 to 80 ohms)
    . pins 2 and 3 (>10 megohms)
    . pin 2 and the ground (>10 megohms).
         a If the resistance values are in the specified limits:
         b If the resistance values are out of the specified limits:
Subtask 77-10-00-810-069-C ** ON A/C NOT FOR ALL
A. The failure message is generated if both channel A and channel B signals are invalid or out of range.
   (1) If the failure messages N2 SNSR, J7, ECU and N2 SNSR, J8, ECU are not confirmed:
     (a) No maintenance action is required.
   (2) If the failure messages N2 SNSR, J7, ECU and N2 SNSR, J8, ECU are not confirmed but are repetitive:
  • disconnect HJ7 harness from the N2 sensor (N2-A connector) and disconnect HJ8 harness from the N2 sensor (N2-B connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do a cleaning of the connectors and receptacles using a BRUSH - BRISTLED with stoddard solvent (Material No.CP2011) AMM 73-21-50-210-002.
     (b) If the failure continues during the subsequent flights:
     (c) If the failure continues during the subsequent flights:
     (d) If the failure continues during the subsequent flights:
     (e) If the failure continues during the subsequent flights:
   (3) If the failure message N2 SNSR, J7, ECU is confirmed:
  • disconnect the HJ7 harness from the N2 sensor (N2-A connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the N2 sensor (4001EV) (channel A) between:
    . pins 1 and 2 (40 to 80 ohms)
    . pins 1 and 3 (>10 megohms)
    . pin 1 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • connect the HJ7 harness to the N2 sensor.
     (b) Disconnect connector HJ7 from the ECU (4000KS) receptacle and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the HJ7 harness between:
    . pins 2 and 11 (40 to 80 ohms)
    . pins 2 and 3 (>10 megohms)
    . pin 2 and the ground (>10 megohms).
         a If the resistance values are in the specified limits:
         b If the resistance values are out of the specified limits:
   (4) If the failure message N2 SNSR, J8, ECU is confirmed:
  • disconnect the HJ8 harness from the N2 sensor (N2-B connector).
     (a) Visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the N2 sensor (4001EV) (channel B) between:
    . pins 1 and 2 (40 to 80 ohms)
    . pins 1 and 3 (>10 megohms)
    . pin 1 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • connect the HJ8 harness to the N2 sensor.
     (b) Disconnect connector HJ8 from the ECU (4000KS) receptacle and visually examine the receptacles and the connectors for damaged pins or contamination AMM 73-21-50-210-002.
       1 If damage is found:
  • repair or replace as required.
       2 If no damage is found:
  • do the electrical resistance test through the HJ8 harness between:
    . pins 2 and 11 (40 to 80 ohms)
    . pins 2 and 3 (>10 megohms)
    . pin 2 and the ground (>10 megohms).
         a If the resistance values are in the specified limits:
         b If the resistance values are out of the specified limits:
Subtask 77-10-00-710-089-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.A.
   (1) No additional maintenance action is required if the fault is not confirmed.
   (2) Repeat the fault isolation procedure if the fault continues.
[Rev.8 from Aug 2018] 2026.04.04 04:37:38 UTC
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