EEC/PMA Power Supply Low Voltage Channel A

TASK 73-21-00-810-896-A
EEC/PMA Power Supply Low Voltage Channel A

1. Possible Causes

STATOR - PMA, EEC [4021EV]
W04 HARNESS [4088KS]
ROTOR - PMA, EEC [4020EV]
[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 71-00-00-860-814	Shutdown of the Engine
AMM 71-00-00-860-817	Motor the Engine (Dry Method)
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 73-21-04-000-801	Removal of the Permanent Magnet Alternator (PMA) Stator
AMM 73-21-04-400-801	Installation of the Permanent Magnet Alternator (PMA) Stator
AMM 73-21-05-000-801	Removal of the Permanent Magnet Alternator (PMA) Rotor
AMM 73-21-05-400-801	Installation of the Permanent Magnet Alternator (PMA) Rotor
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
EEC Wiring Harnesses
PMA Wiring Harness
PMA Wiring Schematic

3. Fault Confirmation
Subtask 73-21-00-710-149-A ** ON A/C NOT FOR ALL

A. Do a dry motoring to confirm repair of this fault AMM 71-00-00-860-817.
(1) Shutdown the engine AMM 71-00-00-860-814.
(2) On MCDU screen, check if the fault is displayed on ground scanning report.

NOTE: The Electronic Engine Control (EEC) has detected the voltage output from the Permanent Magnet Alternator (PMA) to the EEC is low in channel A. The PMA is attached to the front of the main gearbox, at the 8 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).

(3) 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.
(4) 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 73-21-00-810-168-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) harness and connector P3 (4000KS-P3) - EEC (4000KS) and connector P11 (4021EV-P11)- PMA (4021EV), for problems which are possible between the EEC (4000KS) and the PMA (4021EV).
(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 W04 HARNESS(4088KS) AMM 73-21-64-000-802 and AMM 73-21-64-400-802.
2 Do the test given in Para. 3.
(3) If no problems are found with the harness, use a PLIERS - JAWED, SOFT to disconnect electrical connector P3 (4000KS-P3) from the EEC (4000KS) and connector P11 (4021EV-P11) from the PMA (4021EV).
(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 electrical connector P3 (4000KS-P3) to the EEC (4000KS) and connector P11 (4021EV-P11) to the PMA (4021EV).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace STATOR - PMA, EEC [4021EV] AMM 73-21-04-000-801 and AMM 73-21-04-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect electrical connector P3 (4000KS-P3) from the EEC (4000KS) and connector P11 (4021EV-P11) from the PMA (4021EV). Use a MULTIMETER - STANDARD to test the PMA (4021EV) 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: Permanent Magnet Alternator Channel A Connector Contacts

W04 (4088KS) Harness P3 (4000KS-P3) EEC (4000KS) Connector Contacts	W04 (4088KS) Harness P11 (4021EV-P11) PMA (4021EV) Connector Contacts
m	2
n	9
p	8
P	3
R	11
S	12

(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 ROTOR - PMA, EEC [4020EV] AMM 73-21-05-000-801 and AMM 73-21-05-400-801.
(b) Do the test given in Para. 3.
(7) 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 73-21-00-860-088-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 04:36:42 UTC