Loss of Data on Bus to FWC, CFDIU and BMC for Engine 1

TASK 73-25-00-810-883-A
Loss of Data on Bus to FWC, CFDIU and BMC for Engine 1

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 73-21-60-000-001	Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001	Installation of the Electronic Control Unit (ECU)
ASM 732505
ASM 732506
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 73-25-00-710-190-A ** ON A/C NOT FOR ALL

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

Subtask 73-25-00-710-190-B ** ON A/C NOT FOR ALL

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

4. Fault Isolation
Subtask 73-25-00-810-120-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message CHECK EIU 1 ARINC OUTPUT CIRCUIT TO 199VC OR EIU 1:

(1) If there is 28VDC:

(2) If the fault continues:

do a check and repair the wiring from the EIU 1 (1KS1) pins AB/5H, 5K to the first terminal block ASM 732506.

(3) If the fault continues:

Subtask 73-25-00-710-191-A ** ON A/C NOT FOR ALL

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

[Rev.8 from Aug 2018] 2026.04.04 04:35:46 UTC