W DOC AIRBUS | TSM A320F

Surge Control Valve (P18) Fault (131-9(A))

TASK 49-00-81-810-871-A
Surge Control Valve (P18) Fault (131-9(A))

1. Possible Causes
  • SCV LVDT PRIMARY SHOWS OPEN CIRCUIT
  • SCV LVDT SECONDARY SHOWS OPEN CIRCUIT
  • SCV TORQUE MOTOR SHOWS OPEN CIRCUIT
  • SCV TORQUE MOTOR SHOWS SHORT CIRCUIT
  • SCV LVDT EXCITATION CIRCUIT FAILURE
  • damage/contamination of electrical connector P18
  • SURGE CONTROL VALVE (P18)
  • aircraft wiring
  • ELECTRONIC CONTROL BOX [59KD]
  • SURGE CONTROL VALVE (8058KM)
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
MULTIMETER - STANDARD
 B. Referenced Information
REFERENCE
DESIGNATION
AMM 49-51-52-000-003
Removal of the Surge Control Valve (131-9(A))
AMM 49-51-52-400-003
Installation of the Surge Control Valve (131-9(A))
ASM 496104
AMM 49-61-34-000-003
Removal of the Electronic Control Box (ECB) (131-9(A))
AMM 49-61-34-400-003
Installation of the Electronic Control Box (ECB) (131-9(A))
3. Fault Confirmation
Subtask 49-00-81-710-062-A ** ON A/C NOT FOR ALL
A. Read-out of ECB Trouble-Shooting Data
   (1) Put the APU MASTER SW to the ON position.
   (2) Get access to the APU LAST LEG/PREVIOUS LEG report.
   (3) Push the '>' adjacent to the related CFDS failure message:
  • the MCDU menu shows:
    SCV LVDT PRIMARY SHOWS OPEN CIRCUIT
    or
    SCV LVDT SECONDARY SHOWS OPEN CIRCUIT
    or
    SCV TORQUE MOTOR SHOWS OPEN CIRCUIT
    or
    SCV TORQUE MOTOR SHOWS SHORT CIRCUIT
    or
    SCV LVDT EXCITATION CIRCUIT FAILURE
   (4) Get access to the APU GND SCANNING menu.
4. Fault Isolation
Subtask 49-00-81-810-058-A ** ON A/C NOT FOR ALL
A. If the APU GND SCANNING menu gives the maintenance message:

SURGE CONTROL VALVE P18

associated with Fault Code Number (FCN) 85, 86, 111 or 112

  • do a check for damage/contamination of electrical connector P18 of the SURGE CONTROL VALVE (P18)
   (1) If the electrical connector P18 is damaged/contaminated:
  • do a repair/cleaning.
   (2) If the electrical connector is OK:
  • use a MULTIMETER - STANDARD to do a resistance check across
    pin 1 and pin 2
    pin 2 and pin 3
    pin 4 and pin 5
    of the SURGE CONTROL VALVE (P18).
     (a) If the resistance check shows OPEN (>1 MOhm) or SHORT (<500 mOhms) circuit, replace the SURGE CONTROL VALVE (P18) AMM 49-51-52-000-003 and AMM 49-51-52-400-003.
     (b) If the resistance values are correct:
  • do a check/repair of the aircraft wiring between
    ECB (59KD) 59KD-AB/J8,D2,D9,J7,G9,G6 and SURGE CONTROL VALVE (P18) P18/3,2,4,5,7,8 ASM 496104.
       1 If the fault continues:
Subtask 49-00-81-810-165-A ** ON A/C NOT FOR ALL
B. If the APU GND SCANNING menu gives the maintenance message:

ECB (59KD)

associated with Fault Code Number (FCN) 84

  • do a check for damage/contamination of electrical connector P18 of the SURGE CONTROL VALVE (P18)
   (1) If the electrical connector P18 is damaged/contaminated:
  • do a repair/cleaning.
   (2) If the electrical connector is OK:
  • do a check/repair of the aircraft wiring between
    ECB (59KD) 59KD-AB/D2,D9,J7,J8,D10 and SURGE CONTROL VALVE (P18) P18/2,4,5,3,1 ASM 496104.
     (a) If the fault continues:
Subtask 49-00-81-810-058-B ** ON A/C NOT FOR ALL
C. If the APU GND SCANNING menu gives the maintenance message:

SURGE CONTROL VALVE (8058KM)

associated with Fault Code Number (FCN) 85, 86, 111 or 112

  • do a check for damage/contamination of electrical connector P18 of the SURGE CONTROL VALVE (8058KM)
   (1) If the electrical connector P18 is damaged/contaminated:
  • do a repair/cleaning.
   (2) If the electrical connector is OK:
  • use a MULTIMETER - STANDARD to do a resistance check across
    pin 1 and pin 2
    pin 2 and pin 3
    pin 4 and pin 5
    of the SURGE CONTROL VALVE (8058KM).
     (a) If the resistance check shows OPEN (>1 MOhm) or SHORT (<500mOhms) circuit, replace the SURGE CONTROL VALVE (8058KM) AMM 49-51-52-000-003 and AMM 49-51-52-400-003.
     (b) If the resistance values are correct:
  • do a check/repair of the aircraft wiring between
    ECB (59KD) 59KD-AB/J8,D2,D9,J7,G9,G6 and SURGE CONTROL VALVE (8058KM) P18/3,2,4,5,7,8 ASM 496104.
       1 If the fault continues:
Subtask 49-00-81-810-165-B ** ON A/C NOT FOR ALL
D. If the APU GND SCANNING menu gives the maintenance message:

SURGE CONTROL VALVE (8058KM) / ECB (59KD)

associated with Fault Code Number (FCN) 84

  • do a check for damage/contamination of electrical connector P18 of the SURGE CONTROL VALVE (8058KM)
   (1) If the electrical connector P18 is damaged/contaminated:
  • do a repair/cleaning.
   (2) If the electrical connector is OK:
  • do a check/repair of the aircraft wiring between
    ECB (59KD) 59KD-AB/D2,D9,J7,J8,D10 and SURGE CONTROL VALVE (8058KM) P18/2,4,5,3,1 ASM 496104.
     (a) If the fault continues:
Subtask 49-00-81-710-063-A ** ON A/C NOT FOR ALL
E. Do a check of the APU GND SCANNING menu to verify the fault is not present.
[Rev.8 from Aug 2018] 2026.04.04 04:40:38 UTC
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