W DOC AIRBUS | TSM A320F

Loss of the TLA Resolver Signal through the two Channels on Engine 2

TASK 76-11-00-810-804-A
Loss of the TLA Resolver Signal through the two Channels on Engine 2

1. Possible Causes
  • ECU [4000KS]
  • CTL UNIT-THROTTLE, ENG 2 [8KS2]
  • A/C electrical wiring
  • J3 harness
  • J4 harness
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 71-51-43-000-046
Removal of the ECU (Channel A) Harness
AMM 71-51-43-000-047
Removal of the ECU (Channel B) Harness
AMM 71-51-43-400-046
Installation of the ECU (Channel A) Harness
AMM 71-51-43-400-047
Installation of the ECU (Channel B) Harness
AMM 71-51-44-000-004
Removal of the Electronic Control Unit (ECU) Channel A Harness 238W0904
AMM 71-51-44-000-005
Removal of the Electronic Control Unit (ECU) Channel B Harness 238W0904
AMM 71-51-44-400-004
Installation of the Electronic Control Unit (ECU) Channel A Harness 238W0904
AMM 71-51-44-400-005
Installation of the Electronic Control Unit (ECU) Channel B Harness 238W0904
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 73-21-60-000-001
Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001
Installation of the Electronic Control Unit (ECU)
ASM 732512
AMM 73-29-00-710-040
Operational Test of the FADEC on the ground (with Engine Motoring)
AMM 76-11-19-000-040
Removal of the Throttle Control Unit
AMM 76-11-19-000-042
Removal of the Throttle Control Unit
AMM 76-11-19-400-040
Installation of the Throttle Control Unit
AMM 76-11-19-400-042
Installation of the Throttle Control Unit
3. Fault Confirmation
Subtask 76-11-00-710-056-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 76-11-00-810-055-A ** ON A/C NOT FOR ALL
A. Do this procedure.
NOTE: The fault is triggered by the ECU if both TLA resolver input signals on channel A and B are invalid or out of range. Most probable cause is an electrical wiring failure or an ECU internal failure.
   (1) If the test does not give the maintenance messages TLA SENS, J3, ECU and/or TLA SENS, J4, ECU:
     (a) If the fault repeats on subsequent flights:
       1 If the fault repeats on subsequent flights:
  • Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       2 Do a continuity and insulation check of this wiring.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       3 Do a pin retention check on connectors sockets.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       4 Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connectors.
         a If damage is found:
   (2) If the test gives the maintenance messages TLA SENS, J3, ECU and TLA SENS, J4, ECU (confirmed on two channels):
  • Do the two following steps (3) and (4).
   (3) If the test gives the maintenance message TLA SENS, J3, ECU (confirmed on channel A):
  • Disconnect the J3 harness from the ECU (4000KS) receptacle and visually examine the ECU receptacle and the J3 harness connector for damaged pins or contamination AMM 73-21-50-210-001.
     (a) If damage on a connector is found:
  • replace or repair as required.
     (b) If nothing is found:
  • do an electrical resistance test through the J3 harness between:
    . pins 17 and 30 (30 to 40 ohms)
    . pins 5 and 15 (15 to 25 ohms)
    . pins 29 and 28 (15 to 25 ohms)
    . pins 17 and 16 (> 10 megohms)
    . pins 5 and 16 (> 10 megohms)
    . pins 29 and 16 (> 10 megohms)
    . pin 17 and the ground (> 10 megohms)
    . pin 5 and the ground (> 10 megohms)
    . pin 29 and the ground (> 10 megohms).
       1 If the resistance values are in the specified limits:
       2 If the resistance values are out of the specified limits:
  • disconnect the connector CC at the throttle control unit (8KS2) and do the resistance check at the throttle control unit connector between:
    . pins A, B (30 to 40 ohms)
    . pins C, D (15 to 25 ohms)
    . pins E, F (15 to 25 ohms)
    .pin A and the ground (> 10 megohms)
    .pin B and the ground (> 10 megohms)
    .pin C 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:
  • continue the troubleshooting as follows:
     (c) Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (d) Do a continuity and insulation check of this wiring.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (e) Do a pin retention check on connectors sockets.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (f) Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connector.
       1 If damage is found:
   (4) If the test gives the maintenance message TLA SENS, J4, ECU (confirmed on channel B):
  • Disconnect the J4 harness from the ECU (4000KS) receptacle and visually examine the ECU receptacle and the J4 harness connector for damaged pins or contamination AMM 73-21-50-210-001.
     (a) If damage on a connector is found:
  • replace or repair as required.
     (b) If nothing is found:
  • do an electrical resistance test through the J4 harness between:
    . pins 17 and 30 (30 to 40 ohms)
    . pins 5 and 15 (15 to 25 ohms)
    . pins 29 and 28 (15 to 25 ohms)
    . pins 17 and 16 (> 10 megohms)
    . pins 5 and 16 (> 10 megohms)
    . pins 29 and 16 (> 10 megohms)
    . pin 17 and the ground (> 10 megohms)
    . pin 5 and the ground (> 10 megohms)
    . pin 29 and the ground (> 10 megohms).
       1 If the resistance values are in the specified limits:
       2 If the resistance values are out of the specified limits:
  • disconnect the connector DD at the throttle control unit (8KS2) and do the resistance check at the throttle control unit connector between:
    . pins A, B (30 to 40 ohms)
    . pins C, D (15 to 25 ohms)
    . pins E, F (15 to 25 ohms)
    .pin A and the ground (> 10 megohms)
    .pin B and the ground (> 10 megohms)
    .pin C 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:
  • continue the troubleshooting as follows.
     (c) Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (d) Do a continuity and insulation check of this wiring
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (e) Do a pin retention check on connectors sockets.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (f) Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connector.
       1 If damage is found:
Subtask 76-11-00-810-055-B ** ON A/C NOT FOR ALL
A. Do this procedure.
NOTE: The fault is triggered by the ECU if both TLA resolver input signals on channel A and B are invalid or out of range. Most probable cause is an electrical wiring failure or an ECU internal failure.
   (1) If the test does not give the maintenance messages TLA SNSR, J3, ECU and/or TLA SNSR, J4, ECU:
     (a) If the fault repeats on subsequent flights:
       1 If the fault repeats on subsequent flights:
  • Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       2 Do a continuity and insulation check of this wiring.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       3 Do a pin retention check on connectors sockets.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       4 Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connectors.
         a If damage is found:
   (2) If the test gives the maintenance messages TLA SNSR, J3, ECU and TLA SNSR, J4, ECU (confirmed on two channels):
  • Do the two following steps (3) and (4).
   (3) If the test gives the maintenance message TLA SNSR, J3, ECU (confirmed on channel A):
  • Disconnect the J3 harness from the ECU (4000KS) receptacle and visually examine the ECU receptacle and the J3 harness connector for damaged pins or contamination AMM 73-21-50-210-001.
     (a) If damage on a connector is found:
  • replace or repair as required.
     (b) If nothing is found:
  • do an electrical resistance test through the J3 harness between:
    . pins 17 and 30 (30 to 40 ohms)
    . pins 5 and 15 (15 to 25 ohms)
    . pins 29 and 28 (15 to 25 ohms)
    . pins 17 and 16 (> 10 megohms)
    . pins 5 and 16 (> 10 megohms)
    . pins 29 and 16 (> 10 megohms)
    . pin 17 and the ground (> 10 megohms)
    . pin 5 and the ground (> 10 megohms)
    . pin 29 and the ground (> 10 megohms).
       1 If the resistance values are in the specified limits:
       2 If the resistance values are out of the specified limits:
  • disconnect the connector CC at the throttle control unit (8KS2) and do the resistance check at the throttle control unit connector between:
    . pins A, B (30 to 40 ohms)
    . pins C, D (15 to 25 ohms)
    . pins E, F (15 to 25 ohms)
    .pin A and the ground (> 10 megohms)
    .pin B and the ground (> 10 megohms)
    .pin C 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:
  • continue the troubleshooting as follows:
     (c) Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (d) Do a continuity and insulation check of this wiring.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (e) Do a pin retention check on connectors sockets.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (f) Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connector.
       1 If damage is found:
   (4) If the test gives the maintenance message TLA SNSR, J4, ECU (confirmed on channel B):
  • Disconnect the J4 harness from the ECU (4000KS) receptacle and visually examine the ECU receptacle and the J4 harness connector for damaged pins or contamination AMM 73-21-50-210-001.
     (a) If damage on a connector is found:
  • replace or repair as required.
     (b) If nothing is found:
  • do an electrical resistance test through the J4 harness between:
    . pins 17 and 30 (30 to 40 ohms)
    . pins 5 and 15 (15 to 25 ohms)
    . pins 29 and 28 (15 to 25 ohms)
    . pins 17 and 16 (> 10 megohms)
    . pins 5 and 16 (> 10 megohms)
    . pins 29 and 16 (> 10 megohms)
    . pin 17 and the ground (> 10 megohms)
    . pin 5 and the ground (> 10 megohms)
    . pin 29 and the ground (> 10 megohms).
       1 If the resistance values are in the specified limits:
       2 If the resistance values are out of the specified limits:
  • disconnect the connector DD at the throttle control unit (8KS2) and do the resistance check at the throttle control unit connector between:
    . pins A, B (30 to 40 ohms)
    . pins C, D (15 to 25 ohms)
    . pins E, F (15 to 25 ohms)
    .pin A and the ground (> 10 megohms)
    .pin B and the ground (> 10 megohms)
    .pin C 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:
  • continue the troubleshooting as follows.
     (c) Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (d) Do a continuity and insulation check of this wiring
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (e) Do a pin retention check on connectors sockets.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (f) Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connector.
       1 If damage is found:
Subtask 76-11-00-810-055-C ** ON A/C NOT FOR ALL
A. Do this procedure.
NOTE: The fault is triggered by the ECU if both TLA resolver input signals on channel A and B are invalid or out of range. Most probable cause is an electrical wiring failure or an ECU internal failure.
   (1) If the test does not give the maintenance messages TLA SNSR, J3, ECU and/or TLA SNSR, J4, ECU:
     (a) If the fault repeats on subsequent flights:
       1 If the fault repeats on subsequent flights:
  • Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       2 Do a continuity and insulation check of this wiring.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       3 Do a pin retention check on connectors sockets.
         a if damage is found:
  • replace or repair the above harness.
         b if nothing is found:
  • continue the troubleshooting as follows.
       4 Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connectors.
         a If damage is found:
   (2) If the test gives the maintenance messages TLA SNSR, J3, ECU and TLA SNSR, J4, ECU (confirmed on two channels):
  • Do the two following steps (3) and (4).
   (3) If the test gives the maintenance message TLA SNSR, J3, ECU (confirmed on channel A):
  • Disconnect the J3 harness from the ECU (4000KS) receptacle and visually examine the ECU receptacle and the J3 harness connector for damaged pins or contamination AMM 73-21-50-210-002.
     (a) If damage on a connector is found:
  • replace or repair as required.
     (b) If nothing is found:
  • do an electrical resistance test through the J3 harness between:
    . pins 17 and 30 (30 to 40 ohms)
    . pins 5 and 15 (15 to 25 ohms)
    . pins 29 and 28 (15 to 25 ohms)
    . pins 17 and 16 (> 10 megohms)
    . pins 5 and 16 (> 10 megohms)
    . pins 29 and 16 (> 10 megohms)
    . pin 17 and the ground (> 10 megohms)
    . pin 5 and the ground (> 10 megohms)
    . pin 29 and the ground (> 10 megohms).
       1 If the resistance values are in the specified limits:
       2 If the resistance values are out of the specified limits:
  • disconnect the connector CC at the throttle control unit (8KS2) and do the resistance check at the throttle control unit connector between:
    . pins A, B (30 to 40 ohms)
    . pins C, D (15 to 25 ohms)
    . pins E, F (15 to 25 ohms)
    .pin A and the ground (> 10 megohms)
    .pin B and the ground (> 10 megohms)
    .pin C 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:
  • continue the troubleshooting as follows:
     (c) Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (d) Do a continuity and insulation check of this wiring.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (e) Do a pin retention check on connectors sockets.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (f) Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connector.
       1 If damage is found:
   (4) If the test gives the maintenance message TLA SNSR, J4, ECU (confirmed on channel B):
  • Disconnect the J4 harness from the ECU (4000KS) receptacle and visually examine the ECU receptacle and the J4 harness connector for damaged pins or contamination AMM 73-21-50-210-002.
     (a) If damage on a connector is found:
  • replace or repair as required.
     (b) If nothing is found:
  • do an electrical resistance test through the J4 harness between:
    . pins 17 and 30 (30 to 40 ohms)
    . pins 5 and 15 (15 to 25 ohms)
    . pins 29 and 28 (15 to 25 ohms)
    . pins 17 and 16 (> 10 megohms)
    . pins 5 and 16 (> 10 megohms)
    . pins 29 and 16 (> 10 megohms)
    . pin 17 and the ground (> 10 megohms)
    . pin 5 and the ground (> 10 megohms)
    . pin 29 and the ground (> 10 megohms).
       1 If the resistance values are in the specified limits:
       2 If the resistance values are out of the specified limits:
  • disconnect the connector DD at the throttle control unit (8KS2) and do the resistance check at the throttle control unit connector between:
    . pins A, B (30 to 40 ohms)
    . pins C, D (15 to 25 ohms)
    . pins E, F (15 to 25 ohms)
    .pin A and the ground (> 10 megohms)
    .pin B and the ground (> 10 megohms)
    .pin C 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:
  • continue the troubleshooting as follows.
     (c) Do a check of the electrical wiring between the throttle control unit (8KS2) and the ECU (4000KS) ASM 732512.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (d) Do a continuity and insulation check of this wiring
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (e) Do a pin retention check on connectors sockets.
       1 if damage is found:
  • replace or repair the above harness.
       2 if nothing is found:
  • continue the troubleshooting as follows.
     (f) Do a check for absence of corrosion or contamination. Pay particular attention to engine to pylon connector.
       1 If damage is found:
Subtask 76-11-00-710-057-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.A.
   (1) No additionnal 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 04:37:24 UTC
"WTRUIB" 2025