- Visually examine the HMU receptacle and the J7 and J8 harness connectors for damaged pins, contamination and fuel wetting (Ref. AMM TASK 73-21-50-210-002).
(a) If damage on a connector is found:
- replace or repair as required.
(b) If fuel wetting is found:
- replace the defective harness J7, (Ref. AMM TASK 73-21-50-000-040) and (Ref. AMM TASK 73-21-50-400-040) or the defective harness J8, (Ref. AMM TASK 73-21-50-000-041) and (Ref. AMM TASK 73-21-50-400-041).
(c) If nothing is found:
- no further action is required.
(2) If the test does not give the maintenance messages J7, HMU (FMVRES), ECU + J8, HMU, but are repetitive after the troubleshooting per step 4.A.(1) has been fully done:
- replace the harness J7, (Ref. AMM TASK 73-21-50-000-040) and (Ref. AMM TASK 73-21-50-400-040).
(a) If the fault continues during the subsequent flights:
- replace the harness J8, (Ref. AMM TASK 73-21-50-000-041) and (Ref. AMM TASK 73-21-50-400-041).
(b) If the fault continues during the subsequent flights:
- replace the ECU (4000KS), (Ref. AMM TASK 73-21-60-000-001) and (Ref. AMM TASK 73-21-60-400-001), if not previously replaced.
(3) If the test gives only the maintenance message J7, HMU(FMVRES), ECU (confirmed only on channel A):
- disconnect the J7 harness from the HMU receptacle (HMU-A) (located in the left core compartment) and visually examine the J7 harness connector and the HMU receptacle for damaged pins, contamination and fuel wetting (Ref. AMM TASK 73-21-50-210-002).
(a) If damage on a connector is found:
- Replace or repair as required.
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(b) If fuel wetting is found:
- replace the harness J7, (Ref. AMM TASK 73-21-50-000-040) and (Ref. AMM TASK 73-21-50-400-040).
(c) If nothing is found:
- Do an electrical resistance test through the HMU receptacle between: . pins 16 and 34 (34 to 46 or 85 to 150 Ohms) . pins 35 and 36 (21 to 29 or 44 to 76 Ohms) . pins 18 and 37 (21 to 29 or 44 to 76 Ohms) . pins 16 and 17 (> 10 Megohms) . pins 35 and 17 (> 10 Megohms) . pins 18 and 17 (> 10 Megohms) . pin 16 and the ground (> 10 Megohms) . pin 35 and the ground (> 10 Megohms) . pin 18 and the ground (> 10 Megohms).
1 If the resistance values are out of the specified limits:
_
- replace the Hydromechanical Unit (HMU), (Ref. AMM TASK 73-21-10-000-002) and (Ref. AMM TASK 73-21-10-400-002).
2 If the resistance values are in the specified limits:
_
- reconnect the harness J7, (Ref. AMM TASK 73-21-50-000-040) and (Ref. AMM TASK 73-21-50-400-040) and continue the troubleshooting.
(d) Disconnect the J7 harness from the ECU (4000KS) receptacle and visually examine the J7 harness connector and the ECU (4000KS) receptacle for damaged pins and contamination (Ref. AMM TASK 73-21-50-210-002).
1 If damage on a connector is found:
_ - replace or repair as required.
2 If nothing is found:
_
- Do an electrical resistance test through the J7 harness between: . pins 16 and 34 (34 to 46 or 85 to 150 Ohms) . pins 35 and 36 (21 to 29 or 44 to 76 Ohms) . pins 18 and 37 (21 to 29 or 44 to 76 Ohms) . pins 16 and 17 (> 10 Megohms) . pins 35 and 17 (> 10 Megohms) . pins 18 and 17 (> 10 Megohms) . pin 16 and the ground (> 10 Megohms) . pin 35 and the ground (> 10 Megohms) . pin 18 and the ground (> 10 Megohms).
a If the resistance values are in the specified limits:
_
- replace the ECU (4000KS), (Ref. AMM TASK 73-21-60-000-001) and (Ref. AMM TASK 73-21-60-400-001).
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b If the resistance values are out of the specified limits:
_
- replace the harness J7, (Ref. AMM TASK 73-21-50-000-040) and (Ref. AMM TASK 73-21-50-400-040).
(4) If the test gives only the maintenance message J8, HMU(FMVRES), ECU (confirmed only on channel B):
- disconnect the J8 harness from the HMU receptacle (HMU-B) (located in the left core compartment) and visually examine the J8 harness connector and the HMU receptacle for damaged pins, contamination and fuel wetting (Ref. AMM TASK 73-21-50-210-002).
(a) If damage on a connector is found:
- Replace or repair as required.
(b) If fuel wetting is found: 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A320 Trouble Shooting Manual 排故手册 发动机燃油和控制 2(109)
