Liquid Level Sensor (LLS) Failure

TASK 38-31-00-810-838-A
Liquid Level Sensor (LLS) Failure

1. Possible Causes

SENSOR,LEVEL [41MG]
aircraft wiring
DECODER/ENCODER UNIT B [300RH7]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 23-73-47-000-001	Removal of the Decoder/Encoder Unit B (300RH)
AMM 23-73-47-400-001	Installation of the Decoder/Encoder Unit B (300RH)
AMM 38-31-00-710-009	Operational Test of the Toilet Unit
AMM 38-31-00-740-001	BITE Test of the Vacuum Toilet System
ASM 383111
AMM 38-31-63-000-001	Removal of the Liquid Level Sensor
AMM 38-31-63-400-001	Installation of the Liquid Level Sensor
MCDU Display

3. Fault Confirmation
Subtask 38-31-00-710-123-A ** ON A/C NOT FOR ALL

A. Do a test of the vacuum toilet system AMM 38-31-00-710-009.

Subtask 38-31-00-740-073-A ** ON A/C NOT FOR ALL

B. Do the procedure to get access to the CFDS SYSTEM REPORT/TEST menu PAGE AMM 38-31-00-740-001.

4. Fault Isolation
Subtask 38-31-00-810-140-A ** ON A/C NOT FOR ALL

A. If the LAST/PREVIOUS LEGS Report gives the maintenance message
LIQD LVL SNSR (41MG)
and
the FAP gives the maintenance message MAINTENANCE REQUIRED - WASTE WATER:

replace the SENSOR,LEVEL [41MG] , AMM 38-31-63-000-001 and AMM 38-31-63-400-001.

(1) If the fault continues:

do a check and repair the aircraft wiring , ASM 383111.

(2) If the fault continues:

replace the DECODER/ENCODER UNIT B [300RH7] , AMM 23-73-47-000-001 and AMM 23-73-47-400-001.

Subtask 38-31-00-710-124-A ** ON A/C NOT FOR ALL

B. Test
(1) Do the test as given in paragraph 3. A. to check the correct operation.
(2) After the subsequent flight, make sure that the fault does not continue.

[Rev.8 from Aug 2018] 2026.04.04 04:34:15 UTC