EEC B BUS Fault on EIU-2

TASK 73-25-00-810-A61-A
EEC B BUS Fault on EIU-2

1. Possible Causes

HARNESS-FAN, WF01 [4217KS]
EIU-2 [1KS2]
wiring
[4000KS2]

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	MULTIMETER - STANDARD
No specific	1	PLIERS - JAWED, SOFT

B. Referenced Information

REFERENCE	DESIGNATION
AMM 70-70-00-910-803	SPOP 6 - Cleaning of the Contact Points and Wiring Harnesses
AMM 71-13-00-010-802	Opening of the Fan Cowl Doors
AMM 71-13-00-410-802	Closing of the Fan Cowl Doors
AWM 715135
AMM 73-21-01-000-801	Removal of the Electronic Engine Control (EEC)
AMM 73-21-01-400-801	Installation of the Electronic Engine Control (EEC)
AMM 73-21-61-000-802	Removal of the Electronic Engine Control (EEC) Wiring Harness (WF01)
AMM 73-21-61-400-802	Installation of the Electronic Engine Control (EEC) Wiring Harness (WF01)
AWM 732530
AMM 73-25-34-000-802	Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-802	Installation of the Engine Interface Unit (EIU)
AMM 73-25-34-710-802	Operational Test of the Engine Interface Unit (EIU) with the Centralized Fault Display System (CFDS)

3. Fault Confirmation
Subtask 73-25-00-710-498-A ** ON A/C NOT FOR ALL

A. Do the operational test of the Engine Interface Unit (EIU) with the Centralized Fault Display System (CFDS) to confirm this fault AMM 73-25-34-710-802.

4. Fault Isolation
Subtask 73-25-00-810-342-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Check if a FADEC 2 CH B fault for 28 VDC FAIL comes on.
(a) On the ENG section of maintenance panel 50VU:
1 Release the FADEC GND PWR/2 pushbutton switch (the ON legend comes on).

NOTE: After the FADEC is energized, wait ten seconds before you start the test. If you do not wait ten seconds, the interactive mode stops the EEC self-test and this can cause spurious faults.

2 Push the FADEC GND PWR/2 pushbutton switch (the ON legend goes off).
(b) Check on FADEC 2 CH B ground scanning report if 28 VDC FAIL comes on.
(c) If a FADEC 2 CH B fault for 28 VDC FAIL fault comes on, troubleshoot it first.
(2) If FADEC 2 CH B fault for 28 VDC FAIL fault does not come on:
(a) Open the fan cowl doors on ENG 2 AMM 71-13-00-010-802.
(b) Examine the WF01 (4217KS) harness, connector P2 (4000KS-P2) - EEC (4000KS) and connector P403 (403VC2-A) - pylon junction box, for problems which are possible between the EEC (4000KS) and the pylon junction box.
1 Inspect for harness damage.
2 Inspect for loose or damaged connectors.

NOTE: Loose connectors must be disconnected and examined for further wear or damage.

3 If a problem is found with the harness or connectors:
a Replace HARNESS-FAN, WF01 [4217KS] AMM 73-21-61-000-802 and AMM 73-21-61-400-802.
b Do the test given in Para. 3.
(3) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P2 (4000KS-P2) from the EEC (4000KS) and connector P403 (403VC2-A) from the pylon junction box.
(a) Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face. Replace parts as necessary.
(b) Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across connector face AMM 70-70-00-910-803.
(c) Reconnect the electrical connector P2 (4000KS-P2) to the EEC (4000KS) and connector P403 (403VC2-A) to the pylon junction box.
(d) Do the test given in Para. 3.
(4) Disconnect the electrical connectors P403 (403VC2-A) from the pylon junction box and P2 from the EEC (4000KS).
(5) Use a MULTIMETER - STANDARD to test the P2/403VC2-A circuits in the harness AWM 715135 sheet 2. Refer to Table 1. Look for:
(a) Wire-to-wire shorts
(b) Shorts to ground
(c) Continuity (less than 5 ohms resistance).

NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.

Table 1: P2/403VC2-A Connector Contacts

(403VC2-A) Connector AA Contacts	P2 Connector AA Contacts
36	c
18	B

(6) If a problem is found:
(a) Replace HARNESS-FAN, WF01 [4217KS] AMM 73-21-61-000-802 and AMM 73-21-61-400-802.
(b) Do the test given in Para. 3.
(7) If no problem is found or if the fault continues:
(a) Remove EIU-2 [1KS2] AMM 73-25-34-000-802.
(8) Disconnect the electrical connector P403 (403VC2-A) from the pylon junction box.
(9) Test the EIU-2/403VC2 circuits in the aircraft wiring AWM 732530. Refer to Table 2. Look for:
(a) Wire-to-wire shorts
(b) Shorts to ground
(c) Continuity (less than 5 ohms resistance).

NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.

Table 2: EIU-2/403VC2 Connector Contacts

(403VC2) Connector AA Contacts	EIU-2 (1KS2) Connector AA Contacts
36	14K
18	15K

(10) If a problem is found:
(a) Repair or replace wiring AWM 732530.
(b) Install EIU-2 [1KS2] AMM 73-25-34-400-802.
(c) Connect electrical connector P403 (403VC2-A) to the pylon junction box .
(d) Do the test given in Para. 3.
(11) If no problem is found or if fault continues:
(a) Replace [4000KS2] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
(b) Do the test given in Para. 3.
(12) If the fault continues:
(a) Replace EIU-2 [1KS2] AMM 73-25-34-000-802 and AMM 73-25-34-400-802.
(b) Do the test given in Para. 3.

5. Close-up
Subtask 73-25-00-860-103-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.

[Rev.8 from Aug 2018] 2026.04.04 04:36:45 UTC