Subaru Legacy 2005 Service Manual page 1230

Engine Lubrication System Trouble in General
LUBRICATION
9. Engine Lubrication System Trouble in General
A: INSPECTION
Before performing diagnosis, make sure that the engine oil level is correct and no oil leakage exists.
Symptom
1) Oil pressure switch
failure
2) Low oil pressure
1. Warning light remains
on.
3) No oil pressure
1) Malfunction of combination meter
2. Warning light does
2) Poor contact of switch contact points
not turn on.
3) Disconnection of wiring
1) Poor contact at terminals
2) Defective wiring harness
3. Warning light flickers
momentarily.
3) Low oil pressure
Possible cause
Cracked diaphragm or oil leakage within switch
Broken spring or seized contacts
Clogging of oil filter
Malfunction of oil by-pass valve in oil filter
Malfunction of oil relief valve in oil pump
Clogged oil passage
Excessive tip clearance and side clearance of oil
pump rotor and gear
Clogged oil strainer or broken pipe
Insufficient engine oil
Broken pipe of oil strainer
Stuck oil pump rotor
LU(H4DOTC)-20
Corrective action
Replace.
Replace.
Replace.
Clean or replace.
Clean or replace.
Clean.
Replace.
Clean or replace.
Replenish.
Replace.
Replace.
Replace.
Replace.
Repair.
Repair.
Repair.
Check for the same
possible causes as
listed in 1) —2).