park assist SUBARU TRIBECA 2009 1.G Service Workshop Manual

PS-50
General Diagnostic Table
POWER ASSISTED SYSTEM (POWER STEERING)
1. NOISE & VIBRATION
CAUTION:
Do not keep the relief valve operated over five seconds at any time or inner parts of the oil pump may
be damaged due to rapid increase of fluid temperature.
NOTE:
•A screeching noise may be heard immediately after the engine start in extremely cold conditions. In this
case, if the noise goes off during warm-up there is no abnormal function in the system. This is due to the fluid
characteristics in extremely cold condition.
•The oil pump normally makes a small whining noise due to its mechanism. Even if a noise is heard when
steering wheel is turned at stand still, there is no abnormal function in the system provided that the noise
eliminates when the vehicle is driving.
•When turning the steering wheel with the brake applied when the vehicle is parked, a screeching noise
may be generated by the brake disc and pads. This is not a fault in the steering system.
•There may be a small vibration around the steering devices when turning the steering wheel at standstill,
even though the component parts are operating properly.
Hydraulic systems are likely to generate this kind of vibration as well as working noise and fluid noise be-
cause of combined conditions, i.e., road surface and tire surface, engine speed and turning speed of steering
wheel, fluid temperature and braking condition.
These conditions do not indicate a problem in the system.
Confirm vibration for an AT model, by applying the parking brake on a concrete surface, shifting into the “D”
range, and turning the steering wheel repeatedly from slow to rapid, step by step.
Tr o u b l e P o s s i b l e c a u s e C o r r e c t i v e a c t i o n
Hiss noise (continuous)
While engine is running.
Relief valve emits operating sound when steering wheel is
completely turned in either direction. (Do not keep this
condition over five seconds.)
Normal
Relief valve emits operating sound when steering wheel is
not turned. This means that the relief valve is defective. Replace the oil pump.
Rattling noise (intermittent)
While engine is running.
Interference with adjacent parts
Check the clearance.
Correct if necessary.
Pipe Assembly.>
Loosened installation of oil pump, oil tank, pump bracket,
gearbox or crossmemberRetighten.
Loose oil pump pulley or other pulley(s) Retighten.
Looseness of linkage, play of steering, improper tightening
(looseness) of suspension joint or steering columnRetighten or replace.
Sound generates from the inside of gearbox or oil pump.Replace faulty parts in the gear-
box or oil pump.
Knocking
When turning steering wheel in
both directions with small angle
repeatedly at engine ON or OFF.
Excessive backlash
Loosened lock nut for adjusting backlashAdjust and retighten.
Insufficient tightening or play in the tie–rod or tie–rod end Retighten or replace.
Grinding noise (continuous)
While engine is running.
Air in vane pump
Inspect and retighten the fluid
line connection.
Refill the fluid and vent air.
Va n e p u m p s e i z i n g R e p l a c e t h e o i l p u m p.
Oil pump pulley bearing seized Replace the oil pump.
Folded hose, flattened pipe Replace.
Squeal, squeak (intermittent or
continuous)
While engine is running.
Improper adjustment of pulley belt
Damaged or over tensioned pulley belt
Unequal length of pulley belts
Adjust or replace.
(Replace two belts as a set.)
Runout or dirty V–groove surface of oil pump pulley Clean or replace.

PS-51
General Diagnostic Table
POWER ASSISTED SYSTEM (POWER STEERING)
Sizzling noise (continuous)
While engine is running.
Fluid aeration
Fix the faulty part causing aera-
tion.
Replace the fluid and vent air.
Damaged pipe of gearbox Replace the pipe.
Fa u lt y i n si de of h os e o r pi p e
Flattened hose or pipeRepair or replace.
Abnormal inside of oil tank Replace.
Removed oil tank cap Install cap.
Whistle (continuous)
While engine is running.Fa u lt y p i pe of g ea r b ox o r fa ul t y h os eReplace the faulty parts of the
gearbox or the hose.
Whine or growl (intermittent or
continuous)
While engine is running with/
without steering turned.
Looseness of oil pump, oil pump bracket attachment Retighten.
Fa u lt in s id e o f oi l p u mp o r h os e
Replace the oil pump or hose, if
the noise can be heard when
vehicle is running as well as
being stopped.
To r q u e c o n v e r t e r g r o w l , a i r c o n d i t i o n e r c o m p r e s s i o n g r o w lRemove the power steering pul-
ley belt and check.
Grinding noise (continuous)
While engine is running with the
steering turned.
Fa u lt in s id e o f ge a rb oxReplace the faulty parts of gear-
box.
Fa u lt y s t ee r i ng sh af t b ea r i ng A pp l y gr ea s e o r r e p la ce.
Occurs when turning the steering wheel with brakes (ser-
vice or parking) applied.
If the noise goes off when brake
is released, it is normal.
Vibration
While engine is running with/
without steering turned.
Engine speed is too low. Adjust, and notify customer.
Air in vane pumpRepair faulty part
Ve n t a i r.
Damaged valve in oil pump or gearboxReplace the faulty parts in gear-
box and oil pump.
Excessive play in steering, looseness of suspension parts Retighten.
Tr o u b l e P o s s i b l e c a u s e C o r r e c t i v e a c t i o n