General Diagnostic Table - Subaru IMPREZA 2002 Service Manual

GENERAL DIAGNOSTIC TABLE
POWER ASSISTED SYSTEM (POWER STEERING)
1O.General Diagnostic Table
A: INSPECTION
Trouble
ieavy steering effort in all
ges
ieavy steering effort at
nd still
steering wheel surges when
ling.
/chicle leads to one side or
other.
'oar return of steering wheel
:enter
Steering wheel surges when
ning.
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*l
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-66, INSPECTION,
Oil Pump.>
6. Measure steering effort.<Ref. to PS-74, 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-74, INSPECTION, Gen-
eral Diaanostic Table.>
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.
*1 If the 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 the mea-
sured 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 the
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.
PS-74