W DOC AIRBUS | TSM A320F

Failure of the VSV System on Engine 1

TASK 75-32-00-810-811-A
Failure of the VSV System on Engine 1

1. Possible Causes
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 72-31-00-290-001
Inspection of the High Pressure Compressor Rotor Assembly
AMM 72-31-00-290-002
Inspection of the High Pressure Compressor Rotor Assembly
AMM 73-21-10-000-001
Removal of the Hydromechanical Unit (HMU)
AMM 73-21-10-000-002
Removal of the Hydromechanical Unit (HMU)
AMM 73-21-10-400-001
Installation of the Hydromechanical Unit (HMU)
AMM 73-21-10-400-002
Installation of the Hydromechanical Unit (HMU)
AMM 73-21-50-000-007
Removal of J8 Harness
AMM 73-21-50-000-041
Removal of the HJ8 Harness for SAC Engines
AMM 73-21-50-400-007
Installation of the J8 Harness
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)
3. Fault Confirmation
Subtask 75-32-00-710-068-A ** ON A/C NOT FOR ALL
A. Test
   (1) Do the operational test of the FADEC 1B on the ground (with engine motoring) AMM 73-29-00-710-040.
4. Fault Isolation
Subtask 75-32-00-810-060-A ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message VSV ACT, HMU:
   (1) Do a resistance check of the J8 cable.
  • Disconnect the cable J8 from the ECU and do a check of the J8 cable resistance between pins 25 and 26.
    The resistance must be between 17 and 23 ohms.
   (2) If the resistance is in the limits, manually operate the VSV system and make sure that the system moves smoothly and freely AMM 72-31-00-290-001.
  • If you find binding, correct the cause as necessary.
   (3) If the resistance is not in the limits, do a resistance check on the HMU.
  • Disconnect the cable J8 from the HMU and do a check of the HMU resistance between pins 25 and 26.
    The resistance must be between 17 and 23 ohms.
   (4) If the HMU resistance values are in the specified limits, replace the defective harness J8 AMM 73-21-50-000-007 and AMM 73-21-50-400-007.
   (5) If the HMU resistance values are out of the specified limits, replace the HMU-1 [4000KC1] AMM 73-21-10-000-001 and AMM 73-21-10-400-001.
   (6) If the fault continues, replace the ECU [4000KS] AMM 73-21-60-000-001 or AMM 73-21-60-400-001.
Subtask 75-32-00-810-060-B ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message VSV ACT, HMU:
   (1) Do a resistance check of the J8 cable.
  • Disconnect the cable J8 from the ECU and do a check of the J8 cable resistance between pins 25 and 26.
    The resistance must be between 17 and 23 ohms.
   (2) If the resistance is in the limits, manually operate the VSV system and make sure that the system moves smoothly and freely AMM 72-31-00-290-002.
  • If you find binding, correct the cause as necessary.
   (3) If the resistance is not in the limits, do a resistance check on the HMU.
  • Disconnect the cable J8 from the HMU and do a check of the HMU resistance between pins 25 and 26.
    The resistance must be between 17 and 23 ohms.
   (4) If the HMU resistance values are in the specified limits, replace the defective harness J8 AMM 73-21-50-000-041 and AMM 73-21-50-400-041.
   (5) If the HMU resistance values are out of the specified limits, replace the HMU-1 [4000KC1] AMM 73-21-10-000-002 and AMM 73-21-10-400-002.
   (6) If the fault continues, replace the ECU [4000KS] AMM 73-21-60-000-001 or AMM 73-21-60-400-001.
Subtask 75-32-00-710-069-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:37:12 UTC
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