DOC AIRBUS | TSM A320FCenter Tank Low Level Sensor 22QJ
TASK 28-46-00-810-848-A
Center Tank Low Level Sensor 22QJ
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 28-46-00-865-072-A
Subtask 28-46-00-810-097-C ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:29:18 UTC
Center Tank Low Level Sensor 22QJ
WARNING:
OBEY THE FUEL SAFETY PROCEDURES.
WARNING:
WHEN YOU DO WORK ON THE FUEL SYSTEM WIRING, YOU MUST USE TEST EQUIPMENT THAT IS APPROVED (REFER TO INTERNATIONAL OR NATIONAL SPECIFICATIONS FOR INTRINSICALLY SAFE TEST EQUIPMENT: EN50020, UL913 OR EQUIVALENT). TEST EQUIPMENT THAT IS NOT APPROVED CAN CAUSE FIRE OR AN EXPLOSION.
1. Possible Causes- FLSCU-2 [9QJ]
- aircraft wiring
- HARNESS-CHAN B, CTR TK [18QT]
- SENSOR-LOW LVL, R CTR TK CHANNEL B [22QJ]
- fused adaptor at 7512VC
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | MULTIMETER - STANDARD |
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 28-46-00-810-818-A | FLSCU1(2) 7QJ(9QJ) |
| ESPM 2053210 | |
| AMM 28-10-00-910-001 | Safety Procedures When You Do Work in a Fuel Tank |
| AMM 28-10-00-910-002 | Access to the Fuel Tanks and the Work Areas |
| AWM 282107 | |
| AWM 282108 | |
| AWM 282603 | |
| AMM 28-42-44-000-001 | Removal of the Center Tank Harness |
| AMM 28-42-44-400-001 | Installation of the Center Tank Harness |
| AMM 28-46-00-740-001 | Functional (BITE) Test |
| ASM 284603 | |
| AWM 284606 | |
| AWM 284609 | |
| AMM 28-46-15-000-004 | Removal of the Center-Tank Fuel-Level Sensors |
| AMM 28-46-15-400-012 | Installation of the Center-Tank Fuel-Level Sensors |
| AMM 28-46-34-000-001 | Removal of the Fuel-Level Sensing Control-Unit (FLSCU) |
| AMM 28-46-34-400-001 | Installation of the Fuel-Level Sensing Control-Unit (FLSCU) |
| AMM 32-12-00-010-001 | Open the Main Gear Doors for Access |
Subtask 28-46-00-865-072-A
A. Table of the circuit breakers referred to in this procedure:
Subtask 28-46-00-740-068-B ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | FUEL/CTR TK/PUMPS1 AND 2/CTL AND IND | 32QA | R26 |
| ** ON A/C NOT FOR ALL | |||
| 121VU | FUEL/CTR TK/L&R XFR/CTL & IND | 2QL | R26 |
B. Test
(1) Do the BITE test of the FLSS AMM 28-46-00-740-001.
(3) If a fault message(s) for one or more of the other FLSS sensors and/or the FLSCU-2 (9QJ) is shown:
(4) If the message 284615 C LO LEVEL SENSOR 22QJ:
Subtask 28-46-00-740-068-C ** ON A/C NOT FOR ALL (1) Do the BITE test of the FLSS AMM 28-46-00-740-001.
NOTE: The 28VDC power supply for the FLSCU-2 (9QJ) low level channel 22QJ/(LS6) is from the C/B-32QA.
(2) Examine the FLSS STATUS page on the MCDU. (3) If a fault message(s) for one or more of the other FLSS sensors and/or the FLSCU-2 (9QJ) is shown:
(4) If the message 284615 C LO LEVEL SENSOR 22QJ:
- is shown, do Para. 4.A.
- is not shown, no work steps are necessary.
NOTE: You can get more data from the:
- Aircraft Maintenance Manual (AMM) Chap. 28-46-00, the Fuel Level Sensing System, Description and Operation (D and O)
- Trouble Shooting Manual (TSM) - Task Supporting Data (Ref. P. Block 301)
- Aircraft Schematic Manual (ASM) ASM 284603.
- Input Parameters Page 3 (Ref. P. Block 301), used with the Fuel Level Sensors Operating (Changeover) Values (Ref. P. Block 301)
- FLSCU Trouble-shooting Data (Ref. P. Block 301).
NOTE: OPTIONAL TESTING:
Where a PSD A320-2 Fuel Level Sensing Test Set is available measurements can be taken before a decision is made to go into or close up a fuel tank. The Test Set enables the tank mounted components and tank wiring to be tested from the tank wall connectors.
Where a PSD A320-2 Fuel Level Sensing Test Set is available measurements can be taken before a decision is made to go into or close up a fuel tank. The Test Set enables the tank mounted components and tank wiring to be tested from the tank wall connectors.
B. Test
(1) Do the BITE test of the FLSS AMM 28-46-00-740-001.
(3) If a fault message(s) for one or more of the other FLSS sensors and/or the FLSCU-2 (9QJ) is shown:
(4) If the message 284615 C LO LEVEL SENSOR 22QJ:
4. Fault Isolation(1) Do the BITE test of the FLSS AMM 28-46-00-740-001.
NOTE: The 28VDC power supply for the FLSCU-2 (9QJ) low level channel 22QJ/(LS6) is from the C/B-2QL.
(2) Examine the FLSS STATUS page on the MCDU. (3) If a fault message(s) for one or more of the other FLSS sensors and/or the FLSCU-2 (9QJ) is shown:
(4) If the message 284615 C LO LEVEL SENSOR 22QJ:
- is shown, do Para. 4.A.
- is not shown, no work steps are necessary.
NOTE: You can get more data from the:
- Aircraft Maintenance Manual (AMM) Chap. 28-46-00, the Fuel Level Sensing System, Description and Operation (D and O)
- Trouble Shooting Manual (TSM) - Task Supporting Data (Ref. P. Block 301)
- Aircraft Schematic Manual (ASM) ASM 284603.
- Input Parameters Page 3 (Ref. P. Block 301), used with the Fuel Level Sensors Operating (Changeover) Values (Ref. P. Block 301)
- Trouble-shooting Data (Ref. P. Block 301).
NOTE: OPTIONAL TESTING:
Where a PSDA321-1 Test Set is available, a check can be made before a decision is made to go into or close up a fuel tank. The Test Set enables a GO/NOGO check to be made of the tank mounted components and wiring from the tank wall connectors.
Where a PSDA321-1 Test Set is available, a check can be made before a decision is made to go into or close up a fuel tank. The Test Set enables a GO/NOGO check to be made of the tank mounted components and wiring from the tank wall connectors.
Subtask 28-46-00-810-097-C ** ON A/C NOT FOR ALL
A. Procedure
(1) Do the steps applicable to the test equipment available.
(2) Test Equipment
(4) Disconnect the free connector 7512VC-A from the receptacle 7512VC.
(5) Do a resistance check of the sensor 22QJ at the tank wall connector 7512VC between pins <B and <C AWM 284609.
Make sure the resistance is between 330 and 480 ohms.
If there is:
(7) If the fault continues:
(a) Get access to the tank wall connector 7512VC (for the center tank harness 18QT) in the right MLG bay AMM 32-12-00-010-001.
(b) Disconnect the free connector 7512VC-A from the receptacle 7512VC.
(c) Do a check AWM 284609 of the aircraft wiring (sensor input wire - H) between the FLSCU-2 rack connector AB, pin 12A and the tank wall free connector 7512VC-A, pin <B.
(d) Do a check AWM 284609 of the aircraft wiring (sensor input wire - L) between the FLSCU-2 rack connector AB, pin 12B and the tank wall free connector 7512VC-A, pin <C.
(e) Do a check AWM 284606 of the aircraft wiring (FLSCU-2 BITE 2 test command wire) between the FLSCU-2 rack connector AA, pin 15A and the FQIC rack connector AB, pin 12E
(f) Do a check AWM 284609 of the aircraft wiring (FLSCU-2 LS6 output wire) between the FLSCU-2 rack connector AB, pin 2B and the FQIC rack connector AC, pin 1D
(g) Repair all the unserviceable wiring and connectors ESPM 2053210.
(h) Connect the free connector 7512VC-A to the tank wall receptacle 7512VC.
(i) Do the test given in Para. 3.B.
(8) If the fault continues, do a test AWM 282603 with a MULTIMETER - STANDARD to see if 28VDC is available at the FLSCU-2 (9QJ) rack connector AA, pin 1D.
(a) If the 28VDC is available:
1 Do a check of the aircraft wiring AWM 282603 between:
3 Do the test given in Para. 3.B.
(9) If the fault continues or if there is no continuity in Step (5):
(a) Drain, open and vent the tank AMM 28-10-00-910-001 and AMM 28-10-00-910-002.
(b) Do a wiring check of the HARNESS-CHAN B, CTR TK [18QT] AWM 284609 and replace, if necessary AMM 28-42-44-000-001 and AMM 28-42-44-400-001.
(c) If the harness is serviceable, replace the SENSOR-LOW LVL, R CTR TK CHANNEL B [22QJ] AMM 28-46-15-000-004 and AMM 28-46-15-400-012.
Subtask 28-46-00-810-097-D ** ON A/C NOT FOR ALL (1) Do the steps applicable to the test equipment available.
(2) Test Equipment
WARNING:
WHEN YOU DO WORK ON THE FUEL SYSTEM WIRING, YOU MUST USE TEST EQUIPMENT THAT IS APPROVED (REFER TO INTERNATIONAL OR NATIONAL SPECIFICATIONS FOR INTRINSICALLY SAFE TEST EQUIPMENT: EN50020, UL913 OR EQUIVALENT). TEST EQUIPMENT THAT IS NOT APPROVED CAN CAUSE FIRE OR AN EXPLOSION.
(a) If there is: - approved test equipment available, go to Step (3)
- no approved test equipment available, go to Step (6).
(4) Disconnect the free connector 7512VC-A from the receptacle 7512VC.
(5) Do a resistance check of the sensor 22QJ at the tank wall connector 7512VC between pins <B and <C AWM 284609.
Make sure the resistance is between 330 and 480 ohms.
If there is:
- continuity as specified, go to Step (6)
- no continuity as specified (resistance check out of range), go to Step (9).
NOTE: The sensor status (wet or dry) and fuel/air temperature will have an effect on the resistance value.
(6) Replace the FLSCU-2 [9QJ] AMM 28-46-34-000-001 and AMM 28-46-34-400-001. (7) If the fault continues:
(a) Get access to the tank wall connector 7512VC (for the center tank harness 18QT) in the right MLG bay AMM 32-12-00-010-001.
(b) Disconnect the free connector 7512VC-A from the receptacle 7512VC.
(c) Do a check AWM 284609 of the aircraft wiring (sensor input wire - H) between the FLSCU-2 rack connector AB, pin 12A and the tank wall free connector 7512VC-A, pin <B.
(d) Do a check AWM 284609 of the aircraft wiring (sensor input wire - L) between the FLSCU-2 rack connector AB, pin 12B and the tank wall free connector 7512VC-A, pin <C.
(e) Do a check AWM 284606 of the aircraft wiring (FLSCU-2 BITE 2 test command wire) between the FLSCU-2 rack connector AA, pin 15A and the FQIC rack connector AB, pin 12E
(f) Do a check AWM 284609 of the aircraft wiring (FLSCU-2 LS6 output wire) between the FLSCU-2 rack connector AB, pin 2B and the FQIC rack connector AC, pin 1D
(g) Repair all the unserviceable wiring and connectors ESPM 2053210.
(h) Connect the free connector 7512VC-A to the tank wall receptacle 7512VC.
(i) Do the test given in Para. 3.B.
(8) If the fault continues, do a test AWM 282603 with a MULTIMETER - STANDARD to see if 28VDC is available at the FLSCU-2 (9QJ) rack connector AA, pin 1D.
(a) If the 28VDC is available:
- go to stap (9).
1 Do a check of the aircraft wiring AWM 282603 between:
- the FLSCU-2 (9QJ) rack connector AA, pin 1D and the C/B-2QL.
3 Do the test given in Para. 3.B.
(9) If the fault continues or if there is no continuity in Step (5):
(a) Drain, open and vent the tank AMM 28-10-00-910-001 and AMM 28-10-00-910-002.
(b) Do a wiring check of the HARNESS-CHAN B, CTR TK [18QT] AWM 284609 and replace, if necessary AMM 28-42-44-000-001 and AMM 28-42-44-400-001.
(c) If the harness is serviceable, replace the SENSOR-LOW LVL, R CTR TK CHANNEL B [22QJ] AMM 28-46-15-000-004 and AMM 28-46-15-400-012.
A. Procedure
(1) Do the steps applicable to the test equipment available.
(2) Test Equipment
(4) Disconnect the fused adaptor 7512VC-B from the receptacle 7512VC.
(5) Do a resistance check of the sensor 22QJ at the tank wall connector 7512VC between pins <B and <C AWM 284609.
Make sure the resistance is between 330 and 480 ohms.
If there is:
(7) If the fault continues:
(a) Get access to the tank wall connector 7512VC (for the center tank harness 18QT) in the right MLG bay AMM 32-12-00-010-001.
(b) Disconnect the fused adaptor 7512VC-B from the receptacle 7512VC.
(c) Do a check AWM 284609 of the aircraft wiring (sensor input wire - H) between the FLSCU-2 rack connector AB, pin 12A and the fused adaptor 7512VC-B, pin <B.
(d) Do a check AWM 284609 of the aircraft wiring (sensor input wire - L) between the FLSCU-2 rack connector AB, pin 12B and the fused adaptor 7512VC-B, pin <C.
(e) If necessary, replace the fused adaptor at 7512VC .
(g) Do a check AWM 284609 of the aircraft wiring (FLSCU-2 LS6 output wire) between the FLSCU-2 rack connector AB, pin 2B and the FQIC rack connector AB, pin 11K.
(h) Repair all the unserviceable wiring and connectors ESPM 2053210.
(i) Install the fused adaptor between the tank wall receptacle 7512VC and the free connector 7512VC-A.
(j) Do the test given in Para. 3.B.
(8) If the fault continues, do a test AWM 282107 with a MULTIMETER - STANDARD to see if 28VDC is available at the FLSCU-2 (9QJ) rack connector AA, pin 1D.
(a) If the 28VDC is available:
1 Do a check of the aircraft wiring AWM 282108 between:
3 Do the test given in Para. 3.B.
(9) If the fault continues or if there is no continuity in Step (5):
(a) Drain, open and vent the tank AMM 28-10-00-910-001 and AMM 28-10-00-910-002.
(b) Do a wiring check of the HARNESS-CHAN B, CTR TK [18QT] AWM 284609 and replace, if necessary AMM 28-42-44-000-001 and AMM 28-42-44-400-001.
(c) If the harness is serviceable, replace the SENSOR-LOW LVL, R CTR TK CHANNEL B [22QJ] AMM 28-46-15-000-004 and AMM 28-46-15-400-012.
(1) Do the steps applicable to the test equipment available.
(2) Test Equipment
WARNING:
WHEN YOU DO WORK ON THE FUEL SYSTEM WIRING, YOU MUST USE TEST EQUIPMENT THAT IS APPROVED (REFER TO INTERNATIONAL OR NATIONAL SPECIFICATIONS FOR INTRINSICALLY SAFE TEST EQUIPMENT: EN50020, UL913 OR EQUIVALENT). TEST EQUIPMENT THAT IS NOT APPROVED CAN CAUSE FIRE OR AN EXPLOSION.
(a) If there is: - approved test equipment available, go to Step (3)
- no approved test equipment available, go to Step (6).
(4) Disconnect the fused adaptor 7512VC-B from the receptacle 7512VC.
(5) Do a resistance check of the sensor 22QJ at the tank wall connector 7512VC between pins <B and <C AWM 284609.
Make sure the resistance is between 330 and 480 ohms.
If there is:
- continuity as specified, go to Step (6)
- no continuity as specified (resistance check out of range), go to Step (9).
NOTE: The sensor status (wet or dry) and fuel/air temperature will have an effect on the resistance value.
(6) Replace the FLSCU-2 [9QJ] AMM 28-46-34-000-001 and AMM 28-46-34-400-001. (7) If the fault continues:
(a) Get access to the tank wall connector 7512VC (for the center tank harness 18QT) in the right MLG bay AMM 32-12-00-010-001.
(b) Disconnect the fused adaptor 7512VC-B from the receptacle 7512VC.
(c) Do a check AWM 284609 of the aircraft wiring (sensor input wire - H) between the FLSCU-2 rack connector AB, pin 12A and the fused adaptor 7512VC-B, pin <B.
(d) Do a check AWM 284609 of the aircraft wiring (sensor input wire - L) between the FLSCU-2 rack connector AB, pin 12B and the fused adaptor 7512VC-B, pin <C.
(e) If necessary, replace the fused adaptor at 7512VC .
NOTE: The connections for the FLSS sensors are through connections and are not fused.
(f) Do a check AWM 284606 of the aircraft wiring (FLSCU-2 BITE 2 test command wire) between the FLSCU-2 rack connector AA, pin 15A and the FQIC rack connector AB, pin 8K. (g) Do a check AWM 284609 of the aircraft wiring (FLSCU-2 LS6 output wire) between the FLSCU-2 rack connector AB, pin 2B and the FQIC rack connector AB, pin 11K.
(h) Repair all the unserviceable wiring and connectors ESPM 2053210.
(i) Install the fused adaptor between the tank wall receptacle 7512VC and the free connector 7512VC-A.
(j) Do the test given in Para. 3.B.
(8) If the fault continues, do a test AWM 282107 with a MULTIMETER - STANDARD to see if 28VDC is available at the FLSCU-2 (9QJ) rack connector AA, pin 1D.
(a) If the 28VDC is available:
- go to step (9).
1 Do a check of the aircraft wiring AWM 282108 between:
- the FLSCU-2 (9QJ) rack connector AA, pin 1D and the C/B-32QA.
3 Do the test given in Para. 3.B.
(9) If the fault continues or if there is no continuity in Step (5):
(a) Drain, open and vent the tank AMM 28-10-00-910-001 and AMM 28-10-00-910-002.
(b) Do a wiring check of the HARNESS-CHAN B, CTR TK [18QT] AWM 284609 and replace, if necessary AMM 28-42-44-000-001 and AMM 28-42-44-400-001.
(c) If the harness is serviceable, replace the SENSOR-LOW LVL, R CTR TK CHANNEL B [22QJ] AMM 28-46-15-000-004 and AMM 28-46-15-400-012.