Oil Level Sensor Electrical Failure (Single Sensor only in Channel B)

TASK 79-31-21-810-801-A
Oil Level Sensor Electrical Failure (Single Sensor only in Channel B)

1. Possible Causes

OIL QUANTITY SENSOR [4075KS]
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 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 79-31-21-000-801	Removal of the Oil Quantity Sensor
AMM 79-31-21-400-801	Installation of the Oil Quantity Sensor
EEC Wiring Harnesses
Oil Quantity Sensor Wiring Harness
Oil Quantity Sensor Wiring Schematic

3. Fault Confirmation
Subtask 79-31-21-710-050-A ** ON A/C NOT FOR ALL

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

NOTE: The Electronic Engine Control (EEC) has detected the circuit for the oil quantity sensor is open or shorted in channel B. The oil quantity sensor is mounted inside the oil tank on the fan case, 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 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 B, 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 79-31-21-810-050-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 W03 (4087KS) harness, connector P4 (4000KS-P4) - EEC (4000KS) and connector P41 (4075KS-P41) - oil quantity sensor (4075KS), for problems which are possible between the EEC (4000KS) and the oil quantity sensor (4075KS).
(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 W03 HARNESS(4087KS) AMM 73-21-63-000-802 and AMM 73-21-63-400-802.
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 P4 (4000KS-P4) from the EEC (4000KS) and connector P41 (4075KS-P41) from the oil quantity sensor (4075KS).
(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 P4 (4000KS-P4) to the EEC (4000KS) and connector P41 (4075KS-P41) to the oil quantity sensor (4075KS).
(d) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace OIL QUANTITY SENSOR [4075KS] AMM 79-31-21-000-801 and AMM 79-31-21-400-801.
(b) Do the test given in Para. 3.
(5) If the fault continues:
(a) Disconnect the electrical connector P4 (4000KS-P4) from the EEC (4000KS) and connector P41 (4075KS-P41) from the oil quantity sensor (4075KS). Use a MULTIMETER - STANDARD to test the oil quantity sensor (4075KS) circuits in 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: Oil Quantity Sensor Channel B Connector Contacts

W03 (4087KS) Harness P4 (4000KS-P4) EEC (4000KS) Connector Contacts	W03 (4087KS) Harness P41 (4075KS-P41) Oil Quantity Sensor (4075KS) Connector Contacts
A	4
b	5
c	2

(b) If a problem is found with the harnesses or connectors:
1 Replace W03 HARNESS [4087KS] AMM 73-21-63-000-802 and AMM 73-21-63-400-802.
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 79-31-21-860-050-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 04:38:28 UTC