Loss of the Yellow Hydraulic Pressure Switch Signal for the SEC 3

TASK 27-94-00-810-835-A
Loss of the Yellow Hydraulic Pressure Switch Signal for the SEC 3

1. Possible Causes

SEC-3 [1CE3]
wiring of the LOW YELLOW PRESS signal from the SEC 3 (1CE3) COM and MON parts to the first terminal block

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 279227
AMM 27-94-34-000-001	Removal of the SEC
AMM 27-94-34-400-001	Installation of the SEC
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)
AMM 29-10-00-863-002	Pressurize the Yellow Hydraulic System with a Hydraulic Ground Power-Cart
AMM 29-10-00-864-002	Depressurize the Yellow Hydraulic System

3. Fault Confirmation
Subtask 27-94-00-860-066-A

A. Job Set-Up
(1) Pressurize the Yellow hydraulic system AMM 29-10-00-863-002.

Subtask 27-94-00-865-061-A

B. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	FLIGHT CONTROLS/FCDC1/SPLY	20CE1	B10
121VU	FLIGHT CONTROLS/FCDC2/SPLY	20CE2	Q20

Subtask 27-94-00-740-074-A

C. Test
(1) Do the BITE test of the EFCS (Ground Scanning) AMM 27-96-00-740-001.

4. Fault Isolation
Subtask 27-94-00-810-084-B

A. If the BITE test gives the maintenance message:
SEC3 OR WIRING FROM Y HYD PRESS SW2

(1) If the fault continues:

do a check and repair the wiring of the LOW YELLOW PRESS signal from the SEC 3 (1CE3) COM and MON parts to the first terminal block, ASM 279227.
open and close the circuit breakers 20CE1 and 20CE2.

Subtask 27-94-00-740-075-A

B. Do the test given in Para. 3.

5. Close-up
Subtask 27-94-00-860-067-A

A. Depressurize the Yellow hydraulic system AMM 29-10-00-864-002.

[Rev.8 from Aug 2018] 2026.04.04 04:28:14 UTC