VORV LVDT Electrical Failure on Channel A

TASK 79-21-00-810-839-A
VORV LVDT Electrical Failure on Channel A

1. Possible Causes

VARIABLE OIL FLOW REDUCTION VALVE [4069KS]
W04 HARNESS [4088KS]
W03 HARNESS [4087KS]
[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 70-70-00-910-803	SPOP 6 - Cleaning of the Contact Points and Wiring Harnesses
AMM 73-21-00-710-806	Test No.7 - EEC Operation Test (Self Test)
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 73-21-63-000-802	Removal of the Electronic Engine Control (EEC) Wiring Harness (W03)
AMM 73-21-63-400-802	Installation of the Electronic Engine Control (EEC) Wiring Harness (W03)
AMM 73-21-64-000-802	Removal of the Electronic Engine Control (EEC) Wiring Harness (W04)
AMM 73-21-64-400-802	Installation of the Electronic Engine Control (EEC) Wiring Harness (W04)
AMM 78-36-00-010-802	Opening of the Thrust Reverser Cowl-Doors
AMM 78-36-00-410-802	Closing of the Thrust Reverser Cowl-Doors
AMM 79-21-15-000-801	Removal of the Variable Oil Reduction Valve (VORV)
AMM 79-21-15-400-801	Installation of the Variable Oil Reduction Valve (VORV)
EEC Wiring Harnesses
W03/W04 Interconnect Wiring Harness
VORV Wiring Harness
VORV Wiring Schematic

3. Fault Confirmation
Subtask 79-21-00-710-088-A ** ON A/C NOT FOR ALL

A. Do the EEC system interactive test to confirm this fault AMM 73-21-00-710-806.

NOTE: The Electronic Engine Control (EEC) has deleted the Linear Variable Differential Transducer (LVDT) circuit for the Variable Oil Reduction Valve (VORV) is out of range or rate in channel A. The VORV is mounted aft of the compressor intermediate case firewall, located at the 9 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).

(1) If the maintenance message does not come back, examine the harness 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 problem are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(2) 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 AND ENGINE OIL 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 79-21-00-810-090-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Examine the W04 (4088KS) and W03 (4087KS) harnesses, connector P3 (4000KS-P3) - EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and connector P54 (4360KS-P54) - VORV (4069KS), for problems which are possible between the EEC (4000KS) and the VORV (4069KS).
(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 harnesses or connectors:
1 Replace W04 HARNESS (4088KS) AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS (4087KS) AMM 73-21-63-000-802 and AMM 73-21-63-400-802.
3 Do the test given in Para. 3.
(3) If no problems are found with the harnesses, use a PLIERS - JAWED, SOFT to disconnect electrical connector P3 (4000KS-P3) from the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and connector P54 (4360KS-P54) from the VORV (4069KS).
(a) Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed 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 P3 (4000KS-P3) to the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and connector P54 (4360KS-P54) to the VORV (4069KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace VARIABLE OIL FLOW REDUCTION VALVE [4069KS] AMM 79-21-15-000-801 and AMM 79-21-15-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect electrical connector P3 (4000KS-P3) from the EEC (4000KS), interconnect J107 (4101VC)/P107 (4101VC-A) and connector P54 (4360KS-P54) from the VORV (4069KS). Use a MULTIMETER - STANDARD to test the VORV LVDT circuits in the harnesses. 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: VORV LVDT Channel A Connector Contacts

W04 (4088KS) Harness P3 (4000KS-P3) EEC (4000KS) Connector Contacts	W04 (4088KS) HARNESS J107 (4101VC) Connector Contacts	W03 (4087KS) Harness P107 (4101VC-A) Connector Contacts	W03 (4087KS) HARNESS P54 (4069KS-P54) VORV (4069KS) Connector Contacts
V	35	35	9
s	36	36	8
GG	1	1	1
NN	6	6	2
FF	7	7	4

(b) If a problem is found with the harnesses or connectors:
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802, or
2 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802.
3 Do the test given in Para. 3.
(6) If 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 79-21-00-860-078-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 thrust reverser cowl-doors AMM 78-36-00-410-802.

[Rev.8 from Aug 2018] 2026.04.04 04:38:36 UTC