Failure of the Pack Valve Output for Engine 1

TASK 73-25-00-810-865-A
Failure of the Pack Valve Output for Engine 1

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 21-61-34-000-002	Removal of the Air-Conditioning System Controller
AMM 21-61-34-400-002	Installation of the Air-Conditioning System Controller
ASM 732509
AMM 73-25-34-000-040	Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-040	Installation of the Engine Interface Unit (EIU)
AMM 73-25-34-710-040	Operational Test of the Engine Interface Unit
AMM 73-25-34-710-043	Operational Test of the Engine Interface Unit

3. Fault Confirmation
Subtask 73-25-00-710-178-A ** ON A/C NOT FOR ALL

A. Do the operational test of the engine interface unit through the CFDS AMM 73-25-34-710-040.

Subtask 73-25-00-710-178-B ** ON A/C NOT FOR ALL

A. Do the operational test of the engine interface unit through the CFDS AMM 73-25-34-710-043.

4. Fault Isolation
Subtask 73-25-00-810-114-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message CHECK 17HB RELAY CIRCUIT OR EIU 1:

(1) If the fault continues:

(2) If the fault continues:

do a check and repair the wiring from the EIU-1 (1KS1) to the engine start relay (17HB) pin AB/1J to pin AA/Z ASM 732509.

Subtask 73-25-00-810-114-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message CHECK 17HB RELAY CIRCUIT OR EIU 1:

replace the CONT-AIR COND SYSTEM 1 [47HH] and CONT-AIR COND SYSTEM 2 [57HH] AMM 21-61-34-000-002 and AMM 21-61-34-400-002.

NOTE: 47HH and 57HH are part of the new AIR COND system and are the substitute for the 17HB relay circuit.

(1) If the fault continues:

(2) If the fault continues:

do a check and repair the wiring from the EIU-1 (1KS1) to the ACSC (47HH and 57 HH) ASM 732509 between:
1KS1, pin AB/1J to 47HH, pin AB/2A
1KS1, pin AB/1J to 57HH, pin AB/2A.

Subtask 73-25-00-710-179-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:35:43 UTC