Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 40

2A–6 POWER–ASSISTED STEERING SYSTEM

Power Steering Pump

Foaming milky power steering fluid, low fluid level, and
possible low pressure can be caused by air in the fluid, or
loss of fluid due to internal pump leakage. Check for leak
and correct.  Bleed the system. Extremely cold
temperatures will cause air bubbles in the system if the

fluid level is low.  If the fluid level is correct and the pump
still foams, remove the pump from the vehicle and check
housing for cracks.  If the housing is cracked, replace the
pump housing.

Condition

Possible cause

Correction

Low Pressure Due to Steering Pump

Relief valve sticking or inoperative.

Replace relief valve.

Side plate not flat against cam ring.

Replace side plate.

Extreme wear of cam ring.

Replace cam ring.

Scored side plate or rotor.

Replace side plate or rotor.

Vanes sticking in rotor slots.

Repair or replace vanes and rotor.

Cracked or broken side plate.

Replace side plate.

High internal leakage.

Repair internal leakage.

Low Pressure Due to Steering Gear

Scored housing bore.

Replace housing.

Growling Noise In Steering Pump

Excessive back pressure in hoses or
steering unit caused by restriction.

Repair steering unit or pump.

Scored side plate or rotor.

Replace side plate or rotor.

Worn cam ring.

Replace cam ring.

Groaning Noise In Steering Pump

Air in the fluid.

Bleed hydraulic system.

Low fluid level.

Replenish fluid.

Pump mounting loose.

Tighten mounting bolt.

Rattling Noise In Steering Pump

Vanes sticking in rotor slots.

Repair or replace vanes and rotor.

Vane improperly installed.

Repair rotor and vane.

Swishing Noise In Steering Pump

Damaged relief valve.

Replace relief valve.

Whining Noise In Steering Pump

Scored side plate and vanes.

Replace side plate and vanes.

Steering Column Lock System

Condition

Possible cause

Correction

Will Not Unlock

Damaged lock cylinder.

Replace lock cylinder.

Damaged park lock cable.

Replace park lock cable.

Will Not Lock

Lock spring broken or worn.

Replace lock cylinder.

Damaged lock cylinder.

Replace lock cylinder.

Ignition switch stuck.

Repair or replace ignition switch.

Park lock cable damaged.

Replace park lock cable.

Key Cannot be Removed in
“OFF LOCK”

Ignition switch is not set correctly.

Correct ignition switch.

“OFF-LOCK”

Damaged lock cylinder.

Replace lock cylinder.

Faulty shift lock mechanism.

Repair or replace the shift lock
mechanism.

Column

Condition

Possible cause

Correction

Noise in Column

Universal joint loose.

Tighten joint.

Shaft lock snap ring not seated.

Place snap ring in proper position.

POWER–ASSISTED STEERING SYSTEM

2A–7

Turn Signal Switch

This diagnosis covers mechanical problems only. Refer
to 

Turn Signal Switch in Electrical section for electrical

diagnosis.

Condition

Possible cause

Correction

Turn Signal Will Not Stay In Turn
Position

Foreign material or loose parts
preventing movement of yoke.

Repair or replace signal switch.

Broken or missing detent or
canceling spring.

Replace signal switch.

Turn Signal Will Not Cancel

Loose switch mounting screws.

Tighten mounting screws.

Switch or anchor bosses broken.

Replace turn signal switch.

Broken, missing or out of position
detent, return or canceling spring.

Replace turn signal switch.

Worn canceling cam.

Replace turn signal switch.

Turn Signal Difficult To Operate

Turn signal switch arm loose.

Tighten arm screw.

Broken or distorted yoke.

Replace turn signal switch.

Loose or misplaced springs.

Replace turn signal switch.

Foreign parts and/or material.

Repair turn signal switch.

Loose turn signal switch mounting
screws.

Tighten mounting screws.

Turn Signal Will Not Indicate Lane
Change

Broken lane change pressure pad or
spring hanger.

Replace turn signal switch.

Broken, missing or misplaced lane
change spring.

Replace turn signal switch.

Base of wire damaged.

Replace turn signal switch.

Hazard Switch Cannot Be Turned Off

Foreign material between hazard
switch to turn signal switch body.

Repair or replace hazard switch.

No Turn Signal Lights

Electrical failure in chassis harness.

Refer to 

Electrical section.

Inoperative turn signal flasher unit.

Replace flasher unit.

Loose chassis harness connector.

Repair loose connector.

Front or Rear Turn Signal Lights Not
Flashing

Burned-out or damaged turn signal
bulb.

Replace bulb.

High resistance connection to
ground at bulb socket.

Repair bulb socket.

Loose chassis harness connector.

Repair loose connector.

2A–8 POWER–ASSISTED STEERING SYSTEM

General Description

The hydraulic power steering system consists of a pump,
an oil reservoir, a steering unit, a pressure hose and a
return hose.

Power Steering Unit

A02RW001

The power steering unit is rack and pinion type.
The toe–in angle can be adjusted by turning the rod on
each side.
The steering housing cannot be disassembled.

Hydraulic Pump

A02RX002

POWER–ASSISTED STEERING SYSTEM

2A–9

The hydraulic pump is vane-type design.  The submerged
pump has housing and internal parts that are inside the
reservoir and operate submerged in oil.  There are two
bore openings at the rear of the pump housing.  The larger
opening contains the cam ring, pressure plate, thrust
plate, rotor and vane assembly, and end plate.  The
smaller opening contains the pressure line union, flow
control valve and spring.
The flow control orifice is part of the pressure line union.
The pressure relief valve inside the flow control valve
limits the pump pressure.

Pressure Switch

When hydraulic pressure reaches 3430 kPa (500 psi), the
pressure switch of the power steering pump closes
causing the Powertrain Control Module (PCM) to actuate
the throttle valve, which increases the engine rpm to
prevent the overload-induced engine speed slow down.
The switch opens when hydraulic pressure drops to 2940
kPa (430 psi).

Steering Column

431RY00009

WARNING: TO AVOID DEPLOYMENT WHEN
TROUBLE-SHOOTING THE SRS SYSTEM, DO NOT
USE ELECTRICAL TEST EQUIPMENT,  SUCH AS
BATTERY-POWERED OR A/C-POWERED
VOLT-METER, OHMMETER, ETC.,  OR ANY TYPE OF
ELECTRICAL EQUIPMENT OTHER THAN
SPECIFIED IN THIS MANUAL.  DO NOT USE A
NON-POWERED PROBE-TYPE TESTER.

INSTRUCTION IN THIS MANUAL MUST BE
FOLLOWED CAREFULLY, OTHERWISE PERSONAL
INJURY MAY RESULT.
When servicing a vehicle equipped with Supplemental
Restraint System, pay close attention to all WARNINGS
and CAUTIONS.
For detailed explanation about SRS, refer to 

Restraints

section

.