Engine Position Discrete 1 Channel B

TASK 73-00-00-810-937-A
Engine Position Discrete 1 Channel B

1. Possible Causes

HARNESS-FAN, WF01 [4217KS]
[4000KS]

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
TSM TASK 71-00-00-810-834-A	General Troubleshooting Guidelines for Additional Troubleshooting Information
TSM TASK 71-00-00-810-835-A	Component and Harness Intermittent Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
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
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 732503
AWM 732504
EEC Wiring Harnesses
Pylon Junction Box Connections
Engine Position Channel B Wiring Schematic

3. Fault Confirmation
Subtask 73-00-00-710-377-A ** ON A/C NOT FOR ALL

A. Energize the FADEC of the engine that has a fault report
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(2) On the ENG section of maintenance panel 50VU:
(a) Release the FADEC GND PWR/1(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 Electronic Engine Control (EEC) self-test and this can cause spurious faults.

(3) On Multipurpose Control and Display Unit (MCDU) screen, check if the fault is displayed on ground scanning report .

NOTE: The EEC has detected the engine position discrete 1 circuit for EEC channel B is invalid. The engine position discrete 1 circuit is configured using hardwired jumpers in the pylon wiring harness. The EEC is located on the fan case at the 2 o'clock position.

Refer to the general troubleshooting guidelines for additional troubleshooting information (Ref. TSM TASK 71-00-00-810-834).
Refer to the component and harness intermittent troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-835).

(4) If the maintenance message does not come back, examine the harnesses and electrical connectors as described in the component and harness intermittent fault isolation procedure (Ref. TSM TASK 71-00-00-810-835).
(a) If no problems are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(5) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.

4. Fault Isolation

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.

WARNING: REFER TO THE MSDS FOR ALL MATERIAL USED AND THE MANUFACTURER'S SAFETY INSTRUCTIONS FOR ALL EQUIPMENT USED. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.

CAUTION: MAKE SURE YOU REMOVE ELECTRICAL POWER FROM THE EEC BEFORE YOU REMOVE THE ELECTRICAL CONNECTORS. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EEC CAN OCCUR.

Subtask 73-00-00-810-291-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Open the fan cowl doors AMM 71-13-00-010-802.
(2) Examine the WF01 (4217KS) harness, connector P2 (4000KS-P2) - EEC (4000KS) and connector P407 (407VC-A) - Pylon junction box, for problems which are possible between the EEC (4000KS) and the pylon junction box.
(a) Inspect for harness damage.
(b) Inspect for loose or damaged connectors.

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

(c) If a problem is found with the harness or connectors:
1 Replace HARNESS-FAN, WF01 [4217KS] AMM 73-21-61-000-802 and AMM 73-21-61-400-802.
2 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 P407 (407VC-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 the connector face AMM 70-70-00-910-803.
(c) Reconnect the electrical connector P2 (4000KS-P2) to the EEC (4000KS) and connector P407 (407VC-A) to the pylon junction box.
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Disconnect the electrical connector P2 (4000KS-P2) from the EEC (4000KS) and connector P407 (407VC-A) from the pylon junction box. Use a MULTIMETER - STANDARD to test the engine position discrete 1 channel B circuit in the harness. Refer to Table 1. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 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: Engine Position Discrete 1 Channnel B Connector Contacts

WF01 (4217KS) Harness P2(4000KS-P2) EEC (4000KS) Connector Contacts	WF01(4217KS) Harness P407 (407VC-A) Pylon Junction Box Connector Contacts
MM	19
PP	8

(b) If a problem is found with the harness or connectors:
1 Replace HARNESS-FAN, WF01 [4217KS] AMM 73-21-61-000-802 and AMM 73-21-61-400-802.
2 Do the test given in Para. 3.
(c) If no problems are found with the WF01 (4217KS) harness or the fault continues:
1 For fault on ENG1:
Check for continuity between pins 8 and 19 from pylon (407VC1) at pylon junction box, refer to AWM 732503.
2 For fault on ENG2:
Check for continuity between pins 8 and 19 from pylon (407VC2) at pylon junction box, refer to AWM 732504.
3 If a problem is found with the engine position discrete 1 circuit in the pylon harness, repair or replace the pylon harness.
4 Do the test given in Para. 3.
(5) If no problems are found with the pylon harness or the fault continues:
(a) Replace [4000KS] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
(b) Do the test given in Para. 3.

5. Close-up
Subtask 73-00-00-860-214-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.
(2) Close the fan cowl doors AMM 71-13-00-410-802.
(3) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:36:10 UTC