LGCIU Signal Mismatch

TASK 26-22-00-810-805-A
LGCIU Signal Mismatch

1. Possible Causes

RELAY-FLIGHT/GROUND (43WF)
RELAY-AUTO TIME DELAY PUSH (39WF)
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 26-22-00-710-001	Operational Test of the APU Fire-Extinguishing Loop/Squib
ASM 262202
AMM 32-69-00-740-001	BITE Check of Landing-Gear Control Interface-Unit (LGCIU) With Use of MCDU to Ensure that Continuous BITE is Operative

3. Fault Confirmation
Subtask 26-22-00-710-054-A

A. The APU FIRE EXTINGUISHING PANEL 20VU (p/n 330TS08Y) has a fault. Special operation is necessary. Incorrect operation causes the APU fire extinguisher bottle to discharge. Airbus supplies a new 20VU panel that corrects this fault. See TFU 26.22.00.007 for more data.
(1) Maintenance recommendation:
(a) Before the test:

Pull the CIRCUIT BREAKER 30WF on panel 120VU.

(b) During the test:

Push the APU FIRE TEST BUTTON quickly and fully.
Hold it fully during the test.
Release it quickly.

Close the CIRCUIT BREAKER 30WF on panel 120VU.

(2) Do the operational test of the APU fire-extinguishing system AMM 26-22-00-710-001.

4. Fault Isolation
Subtask 26-22-00-810-061-A

A. If the test gives a different maintenance message:

Do the trouble shooting procedure related to the maintenance message.

Subtask 26-22-00-810-060-A

B. If the test gives the maintenance message APU FIRE:

do a check of the RELAY-FLIGHT/GROUND (43WF) and replace it if necessary ASM 262202.

(1) If the fault continues:
do a check of the RELAY-AUTO TIME DELAY PUSH (39WF) and replace it if necessary ASM 262202.
(2) If the fault continues:

do the BITE test of the landing gear AMM 32-69-00-740-001.

(a) If the test gives a different maintenance message:

Do the trouble shooting procedure related to the maintenance message.

(3) If the fault continues:

do a check and repair the wiring if necessary between:
RELAY (43WF) connector A/X1 and LGCIU 1 (5GA1) connector AA/5B,
RELAY (43WF) connector A/A2 and RELAY (39WF) connector A/A2,
RELAY (39WF) connector A/A1 and BODY-LIGHT (40WF),
RELAY (43WF) connector A/A1 and CB (30WF),
RELAY (43WF) connector A/X2 and GND ASM 262202.

Subtask 26-22-00-710-059-A

C. Do the test as given in the Para. 3.A.

5. Close-up
Subtask 26-22-00-860-054-A

A. Put the aircraft back to its initial configuration.

[Rev.8 from Aug 2018] 2026.04.04 04:27:24 UTC