W DOC AIRBUS | TSM A320F

Loss of the feedback signal from the RAC Valve through the Channel B on Engine 1

TASK 75-23-00-810-811-A
Loss of the feedback signal from the RAC Valve through the Channel B on Engine 1

1. Possible Causes
  • harness J12
  • ECU [4000KS]
  • harness CJ12R
  • RACC valve
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 73-21-50-000-004
Removal of the CJ12R Harness
AMM 73-21-50-000-011
Removal of the J12 Harness
AMM 73-21-50-400-004
Installation of the CJ12R Harness
AMM 73-21-50-400-011
Installation of the J12 Harness
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 732518
AMM 73-29-00-710-040
Operational Test of the FADEC on the ground (with Engine Motoring)
AMM 75-23-10-000-001
Removal of the Rotor Active Clearance Control (RACC) Valve
AMM 75-23-10-400-001
Installation of the Rotor Active Clearance Control (RACC) Valve
3. Fault Confirmation
Subtask 75-23-00-710-066-A ** ON A/C NOT FOR ALL
A. Do the operational test of the FADEC 1B on the ground (with engine non motoring) AMM 73-29-00-710-040.
4. Fault Isolation
Subtask 75-23-00-810-058-A ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message RAC VLV, J12, ECU:
  • do a check for open or short to ground of the harness J12 between the ECU (4000KS) and the 6 o'clock junction box, between the 6 o'clock junction box and the RACC valve ASM 732518.
   (1) If the wiring is not correct:
  • repair the above wiring.
   (2) If the wiring is correct:
  • disconnect the cable J12 (channel B) from the ECU (4000KS) and do a resistance check of the cable J12 between:
    . pins 40 and 41 (110 to 135 Ohms)
    . pins 20 and 39 (148 to 181 Ohms)
    . pins 8 and 22 (164 to 200 Ohms)
    . pins 40 and 21 (> 10 Megohms)
    . pins 20 and 21 (> 10 Megohms)
    . pins 8 and 21 (> 10 Megohms)
    . pin 40 and the ground (> 10 Megohms)
    . pin 20 and the ground (> 10 Megohms)
    . pin 8 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:
  • disconnect the cable J12 (channel B) from the cable CJ12R at the 6 o'clock junction box and do a resistance check of the cable CJ12R between:
    . pins 11 and 24 (110 to 135 ohms)
    . pins 22 and 23 (148 to 181 ohms)
    . pins 9 and 21 (164 to 200 ohms)
    . pins 11 and 10 (> 10 Megohms)
    . pins 22 and 10 (> 10 Megohms)
    . pins 9 and 10 (> 10 Megohms)
    . pin 11 and the ground (> 10 Megohms)
    . pin 22 and the ground (> 10 Megohms)
    . pin 9 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 cable CJ12R from the RACC valve and do a resistance check of the RACC valve between:
    . pins 2 and 3 (122 ohms + or - 10 %)
    . pins 4 and 5 (165 ohms + or - 10 %)
    . pins 6 and 7 (182 ohms + or - 10 %)
    . pin 2 and the ground (> 10 Megohms)
    . pin 4 and the ground (> 10 Megohms)
    . pin 6 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 75-23-00-710-067-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:37:04 UTC
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