L(R) High Level Sensor 17QJ1(2)

TASK 28-46-00-810-803-A
L(R) High Level Sensor 17QJ1(2)

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-1 [7QJ]
FLSCU-2 [9QJ]
aircraft wiring
HARNESS-CHAN A, L WING TK INR [13QT1]
HARNESS-CHAN A, R WING TK INR [13QT2]
SENSOR-HI LEVEL, LEFT WING TANK INNER CHANEL A [17QJ1]
SENSOR-HI LEVEL, RIGHT WING TANK INNER CHANEL A [17QJ2]
RELAY-FLSCU 1 SUPPLY [50QJ]
HARNESS-LEFT WING TANK A [57QT]
HARNESS-RIGHT WING, TANK A [58QT]

2. Job Set-up Information
A. Referenced Information

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
AMM 28-42-43-000-005	Removal of the Wing Tank Harness
AMM 28-42-43-000-006	Removal of the Wing-Tank Inner-Cell Group A Harness
AMM 28-42-43-000-008	Removal of the Wing Tank Fuel Quantity Indicating Probe Fused/Shorting Plug Connectors
AMM 28-42-43-400-005	Installation of the Wing Tank Harness
AMM 28-42-43-400-006	Installation of the Wing-Tank Inner-Cell Group A Harness
AMM 28-46-00-740-001	Functional (BITE) Test
ASM 284601
AWM 284601
AWM 284602
AMM 28-46-15-000-001	Removal of the Wing-Tank Fuel-Level Sensors
AMM 28-46-15-400-009	Installation of the Wing-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)

3. Fault Confirmation
Subtask 28-46-00-865-078-A

A. Table of the circuit breakers referred to in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	FUEL/HI/LVL/SPLY	1QJ	L25

Subtask 28-46-00-740-052-A ** ON A/C NOT FOR ALL

B. Test
(1) Do the BITE test of the FLSS AMM 28-46-00-740-001.
(2) Examine the FLSS STATUS page on the MCDU.
(3) If the page shows messages for one or more of the other sensors and/or the FLSCU-1(2), do (Ref. TSM TASK 28-46-00-810-818).
(4) If the message 284615 L(R) HI LEVEL SENSOR 17QJ1(2):

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 284601.

You can get more Trouble-shooting data from the CFDS(FUEL):

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 lets the tank mounted components and tank wiring be tested from the tank wall connectors.

Subtask 28-46-00-740-052-B ** ON A/C NOT FOR ALL

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 284601.

You can get more Trouble-shooting data from the CFDS(FUEL):

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 lets a GO/NOGO check be made of the tank mounted components and wiring from the tank wall connectors.

4. Fault Isolation
Subtask 28-46-00-810-052-A ** ON A/C NOT FOR ALL

A. Procedure
(1) Do the steps applicable to the test equipment available.
(2) Test Equipment.

(a) If there is:

approved test equipment available, go to Step (3)
no approved test equipment available, go to Step (6).

(3) Get access to the tank wall connector 4039VC1(2)-A (for the wing tank harness 13QT1(2)) AMM 28-42-43-000-008.
(4) Disconnect the free connector 4039VC1(2)-A from the receptacle 4039VC1(2).
(5) Do a resistance check of the sensor 17QJ1(2) at the tank wall connector 4039VC1(2) between pins <V and EE AWM 284602.
Make sure the resistance is between 330 and 480 ohms.
If there is:

continuity as specified above, go to Step (6)
no continuity as specified above (resistance check out of range), go to Step (8).

NOTE: The sensor status (wet or dry) and fuel/air temperature will have an effect on the resistance value.

(6) Replace the FLSCU-1 [7QJ] ( 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 4039VC1(2)-A (for the wing tank harness 13QT1(2)) AMM 28-42-43-000-008.
(b) Disconnect the free connector 4039VC1(2)-A from the receptacle 4039VC1(2).
(c) Do a check AWM 284601 and AWM 284602 of the aircraft wiring (sensor input line - H) between the FLSCU-1(2) rack connector AB, pin 10A and the tank wall free connector 4039VC1(2)-A, pin <V.
(d) Do a check AWM 284601 and AWM 284602 of the aircraft wiring (sensor input line - L) between the FLSCU-1(2) rack connector AB, pin 10B and the tank wall free connector 4039VC1(2)-A, pin EE.
(e) Do a check AWM 284601 of the aircraft wiring (FLSCU-1 BITE 1 test command line) between the FLSCU-1 rack connector AA, pin 15B and the FQIC rack connector AB, pin 7H, or the (aircraft wiring (FLSCU-2 BITE 1 test command line) between the FLSCU-2 rack connector AA, pin 15B and the FQIC rack connector AB, pin 10H).
(f) Do a check AWM 284601 of the aircraft wiring (FLSCU-1 LS3 output line) between the FLSCU-1 rack connector AB, pin 2A and the FQIC rack connector AB, pin 6G, or the (aircraft wiring (FLSCU-2 LS3 output line) between the FLSCU-2 rack connector AB, pin 2A and the FQIC rack connector AB, pin 11H).
(g) Repair all the unserviceable wiring and connectors ESPM 2053210.
(h) Connect the free connector 4039VC1(2)-A to the receptacle 4039VC1(2).
(i) Do the test in Para. 3.B.
(8) 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 A, L WING TK INR [13QT1] ( HARNESS-CHAN A, R WING TK INR [13QT2] ) AWM 284602 and replace, if necessary AMM 28-42-43-000-006 and AMM 28-42-43-400-006.
(c) If the harness is serviceable, replace the SENSOR-HI LEVEL, LEFT WING TANK INNER CHANEL A [17QJ1] ( SENSOR-HI LEVEL, RIGHT WING TANK INNER CHANEL A [17QJ2] ) AMM 28-46-15-000-001 and AMM 28-46-15-400-009.

Subtask 28-46-00-810-052-C ** ON A/C NOT FOR ALL

A. Procedure
(1) Do the steps applicable to the test equipment available.
(2) Test Equipment.

(a) If there is:

approved test equipment available, go to Step (3)
no approved test equipment available, go to Step (6).

(3) Get access to the tank wall connector 4039VC1(2)-A (for the wing tank harness 57QT(58QT)) AMM 28-42-43-000-008.
(4) Disconnect the free connector 4039VC1(2)-A from the receptacle 4039VC1(2).
(5) Do a resistance check of the sensor 17QJ1(2) at the tank wall connector 4039VC1(2) between pins <V and EE AWM 284602.
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 (10).

NOTE: The sensor status (wet or dry) and fuel/air temperature will have an effect on the resistance value.

(6) Replace the FLSCU-1 [7QJ] ( 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 4039VC1(2)-A (for the wing tank harness 57QT(58QT)) AMM 28-42-43-000-008.
(b) Disconnect the free connector 4039VC1(2)-A from the receptacle 4039VC1(2).
(c) Do a check AWM 284601 and AWM 284602 of the aircraft wiring (sensor input line - H) between the FLSCU-1(2) rack connector AB, pin 10A and the tank wall free connector 4039VC1(2)-A, pin <V.
(d) Do a check AWM 284601 and AWM 284602 of the aircraft wiring (sensor input line - L) between the FLSCU-1(2) rack connector AB, pin 10B and the tank wall free connector 4039VC1(2)-A, pin EE.
(e) Do a check AWM 284601 of the aircraft wiring (FLSCU-1 BITE 1 test command line) between the FLSCU-1 rack connector AA, pin 15B and the FQIC rack connector AB, pin 14F or the (aircraft wiring (FLSCU-2 BITE 1 test command line) between the FLSCU-2 rack connector AA, pin 15B and the FQIC rack connector AB, pin 12F).
(f) Do a check AWM 284601 of the aircraft wiring (FLSCU-1 LS3 output line) between the FLSCU-1 rack connector AB, pin 2A and the FQIC rack connector AC, pin 4H or the (aircraft wiring (FLSCU-2 LS3 output line) between the FLSCU-2 rack connector AB, pin 2A and the FQIC rack connector AC, pin 1A).
(g) Repair all the unserviceable wiring and connectors ESPM 2053210.
(h) Connect the free connector 4039VC1(2)-A to the receptacle 4039VC1(2).
(i) Do the test in Para. 3.B.
(8) If the fault continues, and the L HI LEVEL SENSOR 17QJ1 was reported:
(a) Do a test, with a multimeter, to see if 28VDC is available at the FLSCU-1 (7QJ) rack connector AA, pin 1B AWM 284601.
(b) If the 28VDC is available:

go to Step (10).

the RELAY-FLSCU 1 SUPPLY [50QJ] .

2 Do a check of AWM 284601 the aircraft wiring (FLSCU-1 (7QJ) 28VDC HI supply) between:

the FLSCU-1 rack connector AA, pin 1B and the RELAY-FLSCU-1 SPLY (50QJ), terminal A2
the RELAY-FLSCU-1 SPLY (50QJ), terminal A3 and the C/B-FUEL/HI/LVL/SPLY (1QJ), terminal 2.

NOTE: In flight the FLSCU-1 (7QJ) rack connector, pin 1B is supplied with 28VDC from the DC BUS 1 through RELAY 39QU to allow the center tank high level sensor 20QJ channel LS7 to remain in operation.
The high level sensor 17QJ1 will remain powered as it also receives 28VDC through the FLSCU-1 rack connector AA, pin 1B.

3 Repair all the unserviceable wiring and connectors ESPM 2053210.
4 Do the test given in Para. 3.B.
(9) If the fault continues, and the R HI LEVEL SENSOR 17QJ2 was reported:
(a) Do a test, with a multimeter, to see if 28VDC is available at the FLSCU-2 (9QJ) rack connector AA, pin 1B AWM 284601.
(b) If the 28VDC is available:

go to Step (10).

(c) If the 28VDC is not available:
1 Do a check of the aircraft wiring (FLSCU-2 (9QJ) 28VDC HI supply) between the FLSCU-2 rack connector AA, pin 1B and the C/B-FUEL/HI/LVL/SPLY (1QJ), terminal 2 AWM 284601.
2 Repair all the unserviceable wiring and connectors ESPM 2053210.
3 Do the test in Para. 3.B.
(10) 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-LEFT WING TANK A [57QT] ( HARNESS-RIGHT WING, TANK A [58QT] ) AWM 284602 and replace, if necessary AMM 28-42-43-000-005 and AMM 28-42-43-400-005.
(c) If the harness is serviceable, replace the SENSOR-HI LEVEL, LEFT WING TANK INNER CHANEL A [17QJ1] ( SENSOR-HI LEVEL, RIGHT WING TANK INNER CHANEL A [17QJ2] ) AMM 28-46-15-000-001 and AMM 28-46-15-400-009.

[Rev.8 from Aug 2018] 2026.04.04 04:29:14 UTC