Failure of the BTC 1 or its Status Contact or Wiring

TASK 24-20-00-810-896-A
Failure of the BTC 1 or its Status Contact or Wiring

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 24-22-55-000-001	Removal of the Contactors
AMM 24-22-55-400-002	Installation of the Contactors
AMM 24-41-00-740-002	Operational Check of the GAPCU via the CFDS

3. Fault Confirmation
Subtask 24-20-00-740-090-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 24-20-00-810-187-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 24-20-00-810-188-A ** ON A/C NOT FOR ALL

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

do a check of the wiring for a short to ground between pin B/29 of the BTC 1 and pin A/4C of the GCU 1 ASM 242202.

(1) If there is a short to ground:

(2) If there is no short to ground:

do a check of the coil return wiring for a short to ground between pin B/5 of the BTC 1 and pin A/9A of the GCU 1 ASM 242202.

(a) If there is a short to ground:

(b) If there is no short to ground:

do a check of the status auxiliary contact for correct operation between pin B/27 and pin B/29 of the BTC 1 (normally open) ASM 242202.

1 If there is no continuity:

2 If there is continuity:

3 If the fault continues:

Subtask 24-20-00-740-091-A ** ON A/C NOT FOR ALL

C. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:26:19 UTC