Subaru Legacy 2003 Service Manual page 3415

POWER ASSISTED SYSTEM (POWER STEERING)
11.General Diagnostic Table
A: INSPECTION
Trouble
• Heavy steering effort in all
ranges
• Heavy steering effort at
stand still
• Steering wheel surges when
turning.
• Vehicle leads to one side or
the other.
• Poor return of steering wheel
to center
• Steering wheel surges when
turning.
*1 If tires and/or rims are wider, the load to power steering system is the more. Accordingly, in a condition, for example before
fluid warms-up, relief valve may work before maximum turning angle. In this case, steering effort may be heavy. When measured
hydraulic pressure is normal, there is no abnormal thing.
*2 In cold weather, steering effort may be heavy due to increased flow resistance of cold fluid. After warming-up engine, turn
steering wheel from stop to stop several times to warm-up fluid. Then if steering effort reduces normally, there is no abnormal
thing.
*3 In cold weather or with insufficient warm-up of engine, steering effort may be heavy due to excessive drop of idling when turn-
ing steering wheel. In this case, it is recommended to start the vehicle with increasing engine speed than usual. Then if steering
effort reduces normally, there is no abnormal thing.
GENERAL DIAGNOSTIC TABLE
Possible cause
1. Pulley belt
• Unequal length of pulley belts
• Adhesion of oil and grease
• Loose or damage of pulley belt
• Poor uniformity of pulley belt cross section
• Pulley belt touches to pulley bottom
• Poor revolution of pulleys except oil pump pulley
• Poor revolution of oil pump pulley
2. Tire and rim
• Improper tires out of specification
• Improper rims out of specification
• Tires not properly inflated*1
3. Fluid
• Low fluid level
• Aeration
• Dust mix
• Deterioration of fluid
• Poor warming-up of fluid *2
4. Idling speed
• Lower idling speed
• Excessive drop of idling speed at start or at turning steering
wheel *3
5. Measure hydraulic pressure.<Ref. to PS-86, INSPECTION,
Oil Pump.>
6. Measure steering effort.<Ref. to PS-94, INSPECTION, Gen-
eral Diagnostic Table.>
1. Fluid line
• Folded hose
• Flattened pipe
2. Tire and rim
• Flat tire
• Mix use of different tires
• Mix use of different rims
• Abnormal wear of tire
• Unbalance of remained grooves
• Unbalance of tire pressure
3. Front alignment
• Improper or unbalance caster
• Improper or unbalance toe-in
• Loose connection of suspension
4. Others
• Damaged joint assembly
• Unbalanced height
• One-sided weight
5. Measure steering effort.<Ref. to PS-94, INSPECTION, Gen-
eral Diagnostic Table.>
PS-94
Corrective action
Adjust or replace.
Replace or reinflate.
Refill, bleed air, replace or
instruct customer.
Adjust or instruct customer.
Replace problem parts.
Adjust or replace.
Reform or replace.
Fix or replace.
Adjust or retighten.
Replace, adjust or instruct cus-
tomer.
Adjust or replace.