Unwanted A/THR 1 and 2 Inoperative Warning

TASK 22-31-00-810-812-A
Unwanted A/THR 1 and 2 Inoperative Warning

1. Possible Causes

RELAY-A/THR1 CMD ENGAGED [17CA1]
RELAY-A/THR1 MON ENGAGED [18CA1]
RELAY-A/THR2 CMD ENGAGED [17CA2]
RELAY-A/THR2 MON ENGAGED [18CA2]
RELAY-A/THR1 INST DISC [5CA1]
RELAY-A/THR2 INST DISC [5CA2]
P/BSW-A/THR INST DISC, CAPT [7CA1]
P/BSW-A/THR INST DISC, F/O [7CA2]
DIODE MODULE (1803VD)
wiring of the engines interface via the relays 5CA1, 5CA2, 17CA1, 17CA2, 18CA1, 18CA2,

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 223101
ASM 732512

3. Fault Confirmation
Subtask 22-31-00-710-072-A

A. Not applicable, you cannot confirm this fault on the ground.

4. Fault Isolation
Subtask 22-31-00-810-067-A

A. Replace the relays RELAY-A/THR1 CMD ENGAGED [17CA1] and RELAY-A/THR1 MON ENGAGED [18CA1] ASM 223101.
(1) If the fault continues:

Replace the RELAY-A/THR2 CMD ENGAGED [17CA2] and RELAY-A/THR2 MON ENGAGED [18CA2] ASM 223101.

(2) If the fault continues:

Replace the relays RELAY-A/THR1 INST DISC [5CA1] and RELAY-A/THR2 INST DISC [5CA2] ASM 223101.

(3) If the fault continues:

Replace the P/BSW-A/THR INST DISC, CAPT [7CA1] and P/BSW-A/THR INST DISC, F/O [7CA2] ASM 223101.

(4) If the fault continues:

(5) If the fault continues:

Do a check of the wiring of the engines interface via the relays 5CA1, 5CA2, 17CA1, 17CA2, 18CA1, 18CA2, ASM 732512.

[Rev.8 from Aug 2018] 2026.04.04 04:25:09 UTC