LPC (2.5) Bleed Valve/Actuator Null Shift Channel A

TASK 75-32-00-810-836-A
LPC (2.5) Bleed Valve/Actuator Null Shift Channel A

1. Possible Causes

ACTUATOR-LPC BLEED VALVE [4092KS]
W04 HARNESS [4088KS]
[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 73-21-00-710-809	Test No.15 - Operation Test (Dry Motor) of the FADEC System Engine Actuators
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 73-21-64-000-802	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 75-32-01-000-801	Removal of the Low Pressure Compressor (LPC) (2.5) Bleed Valve Actuator
AMM 75-32-01-400-801	Installation of the Low Pressure Compressor (LPC) (2.5) Bleed Valve Actuator
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
EEC Wiring Harnesses
2.5 Bleed Valve Actuator Wiring Harness
2.5 Bleed Valve Actuator Wiring Schematic

3. Fault Confirmation
Subtask 75-32-00-710-090-A ** ON A/C NOT FOR ALL

A. Do the FADEC system engine actuators test to confirm this fault. Refer to operational test of the engine actuators AMM 73-21-00-710-809.

NOTE: The Electronic Engine Control (EEC) has detected the 2.5 bleed valve actuator Torque Motor (TM) requires more current to stay in position in channel A. This fault is usually an indication of a problem with the 2.5 bleed valve actuator TM or internal servo valve. The 2.5 bleed valve actuator is mounted on the aft side of the compressor intermediate case bulkhead located at the 10 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 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.
(2) If the maintenance message comes back (hard fault) in channel A, 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 75-32-00-810-094-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) Replace ACTUATOR-LPC BLEED VALVE [4092KS] AMM 75-32-01-000-801 and AMM 75-32-01-400-801.
(a) Do the test given in Para. 3.
(3) If the fault continues:
(a) Examine the W04 (4088KS) harness, connector P5 (4000KS-P5) - EEC (4000KS) and P28 (4092KS-P28) - 2.5 bleed valve actuator (4092KS), for problems which are possible between the EEC (4000KS) and the 2.5 bleed valve actuator (4092KS).
(b) Inspect for harness damage.
(c) Inspect for loose or damaged connectors.

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

(d) If a problem is found with the harness or connectors:
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(4) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector P5 (4000KS-P5) from the EEC (4000KS) and P28 (4092KS-P28) from the 2.5 bleed valve actuator (4092KS).
(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 P5 (4000KS-P5) to the EEC (4000KS) and P28 (4092KS-P28) to the 2.5 bleed valve actuator (4092KS).
(d) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P5 (4000KS-P5) from the EEC (4000KS) and P28 (4092KS-P28) from the 2.5 bleed valve actuator (4092KS). Use a MULTIMETER - STANDARD to test the LPC 2.5 bleed valve actuator (4092KS) Torque Motor (TM) circuits 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: 2.5 Bleed Valve Actuator TM Channel A Connector Contacts

W04 (4088KS) Harness P5 (4000KS-P5) EEC (4000KS) Connector Contacts	W04 (4088KS) Harness P28 (4092KS-P28) 2.5 Bleed Valve Actuator (4092KS) Connector Contacts
Y	7
u	6

(b) If a problem is found with the harness or connectors:
1 Replace W04 HARNESS [4088KS] AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 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 75-32-00-860-055-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 04:37:22 UTC