CPC 1 / SDAC 1+2 Interface Fault

TASK 21-51-00-810-809-A
CPC 1 / SDAC 1+2 Interface Fault

1. Possible Causes

SDAC-1 [1WV1]
wiring
PRESS CONT 1 [11HL]
SDAC-2 [1WV2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 21-31-00-710-002	Operational Test of the Pressure Control and Monitoring
ASM 213103
AMM 21-31-34-000-001	Removal of the Cabin Pressure Controller
AMM 21-31-34-400-001	Installation of the Cabin Pressure Controller
AMM 31-50-00-710-001	Ground Scanning of the Central Warning System
AMM 31-55-34-000-001	Removal of the SDAC
AMM 31-55-34-400-001	Installation of the SDAC

3. Fault Confirmation
Subtask 21-51-00-710-066-A

A. Do the operational test of the central warning system AMM 31-50-00-710-001.

NOTE: Make sure that the circuit breaker 3HL is closed during the test.

4. Fault Isolation
Subtask 21-51-00-810-062-A

A. If the test gives the maintenance message SDAC1: NO CPCU1 DATA 11HL or SDAC1: NO CPC 1 ANALOG SIGNAL:

do the operational test of the pressure control and monitoring system AMM 21-31-00-710-002.

(1) If the test gives a different maintenance message refer to the Fault Symptom List.
(2) If the test is OK:
replace the SDAC-1 [1WV1] AMM 31-55-34-000-001 and AMM 31-55-34-400-001.
(3) If the fault continues:

do a check and repair the wiring ASM 213103:
from the CPC 1 (11HL)AA/1C to the SDAC 1 (1WV1)AE/10F,
from the CPC 1 (11HL)AA/4D to the SDAC 1 (1WV1)AE/10E.

(4) If the fault continues:
replace the PRESS CONT 1 [11HL] AMM 21-31-34-000-001 and AMM 21-31-34-400-001.

Subtask 21-51-00-810-063-A

B. If the test gives the maintenance message SDAC2: NO CPCU1 DATA 11HL or SDAC2: NO CPC1 ANALOG SIGNAL:

do the operational test of the pressure control and monitoring system AMM 21-31-00-710-002.

(1) If the test gives a different maintenance message refer to the Fault Symptom List.
(2) If the test is OK:
replace the SDAC-2 [1WV2] AMM 31-55-34-000-001 and AMM 31-55-34-400-001.
(3) If the fault continues:

do a check and repair the wiring ASM 213103:
from the CPC 1 (11HL)AA/1C to the SDAC 2 (1WV2)AE/10F,
from the CPC 1 (11HL)AA/4D to the SDAC 2 (1WV2)AE/10E.

(4) If the fault continues:
replace the PRESS CONT 1 [11HL] AMM 21-31-34-000-001 and AMM 21-31-34-400-001.

Subtask 21-51-00-810-066-A

C. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:24:47 UTC