Failure of the GCU 1 Pin Programming

TASK 24-20-00-810-932-A
Failure of the GCU 1 Pin Programming

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 242202
AMM 24-22-34-000-001	Removal of the GCU-1(2)
AMM 24-22-34-400-001	Installation of the GCU-1(2)
AMM 24-41-00-740-002	Operational Check of the GAPCU via the CFDS

3. Fault Confirmation
Subtask 24-20-00-740-054-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the BITE test of the GAPCU AMM 24-41-00-740-002.
(a) If the BITE test gives the message TEST FAILED:

(b) If the BITE test gives the message TEST PASSED:

4. Fault Isolation
Subtask 24-20-00-810-181-A ** ON A/C NOT FOR ALL

A. If the BITE test gives the message TEST FAILED:

(1) If the maintenance message GCU1 (1XU1) comes into view:

Subtask 24-20-00-810-125-B ** ON A/C NOT FOR ALL

B. If the BITE test gives the message TEST PASSED:

do a check of the pin programming wiring ASM 242202 of the GCU 1:
. pin A/5A connected to ground
. pin A/3E connected to ground
. pin A/4G connected to ground
. pins A/7C, A/8A, A/2E and A/5E not connected.

NOTE: The wiring diagram of the aircraft interface with the pin programming connections is necessary to do the trouble shooting procedure.

(1) If the wiring is not correct:

(2) If the wiring is correct:

Subtask 24-20-00-740-055-A ** ON A/C NOT FOR ALL

C. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:26:25 UTC