Loss of the Bus Output from the Cabin Pressure Controller 1 to the CFDIU

TASK 31-32-00-810-883-A
Loss of the Bus Output from the Cabin Pressure Controller 1 to the CFDIU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-32-00-869-002	Procedure for the Class 3 Fault Reading
ASM 313204
AMM 31-32-34-000-001	Removal of the CFDIU
AMM 31-32-34-400-001	Installation of the CFDIU

3. Fault Confirmation
Subtask 31-32-00-865-129-A

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	AIR COND/CAB/PRESS/CTL1	1HL	D09

Subtask 31-32-00-740-210-A

B. Test
On the CFDS MENU page, get access to the AVIONICS STATUS page AMM 31-32-00-869-002.

4. Fault Isolation
Subtask 31-32-00-810-132-A

A. If the test gives the maintenance message NO CPC 1 DATA:

(1) If the fault continues:

do a check and repair the wiring from the CFDIU (1TW) pins AA/4B, 4C to the first terminal block ASM 313204.

Subtask 31-32-00-740-211-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:29:54 UTC