Oil Filter Impending Bypass

TASK 79-21-00-810-833-A
Oil Filter Impending Bypass

1. Possible Causes

2. Job Set-up Information
A. 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
TSM TASK 71-00-00-810-874-A	Troubleshoot the Engine after an Oil Filter Clog Warning event

3. Fault Confirmation
Subtask 79-21-00-710-080-A ** ON A/C NOT FOR ALL

A. Not Applicable

NOTE: The Electronic Engine Control (EEC) has sensed the pressure drop across the oil filter differential pressure sensor is large enough to indicate the oil filter is approaching bypass. In this condition, the oil filter bypass valve is still sending pressurized oil through the primary filter element. The oil filter is located on the lubrication and scavenge oil pump at approximately 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).

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 79-21-00-810-084-A ** ON A/C NOT FOR ALL

A. Do the step that follows:
(1) If the maintenance messages related to the oil filter impending bypass on both channels have been set, refer to the observed fault troubleshooting procedure (Ref. TSM TASK 71-00-00-810-874).

5. Close-up
Subtask 79-21-00-860-072-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.

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