General Diagnostic Table: Inspection: Notes

Trouble

Possible cause

Corrective action

Steering effort is heavy in all ranges.
Steering effort is heavy at stand still.
Steering wheel vibrates when turning.

1. Tire and wheel

Improper tire out of specifications⁽¹⁾
Improper wheel out of specifications⁽¹⁾
Tires not properly inflated

Replace or reinflate the tire and wheel.
Perform above or instruct customer.

2. Idle speed

Lower idle speed
Excessive drop of idle speed at start or when turning the steering wheel ⁽³⁾

Adjust the idle speed or instruct customer.

3. Fluid

Low fluid level
Air entry in fluid
Dust entry in fluid
Fluid deterioration
Inadequate warm up of fluid ⁽²⁾

Refill the fluid, bleed air, replace or instruct customer.

4. Pulley belt

Unequal length of pulley belts
Contact with oil or grease
Looseness or damage of the pulley belt
Poor uniformity of the pulley belt cross section
Pulley belt touches to pulley bottom
Poor revolution of pulleys (except oil pump pulley)
Poor revolution of oil pump pulley

Adjust or replace the faulty parts.

5. Fluid line
Fluid leakage from fluid line

Replace the faulty parts.

6. Measure the hydraulic pressure. < Refer to INSPECTION , Oil Pump. >

Replace the faulty parts.

7. Measure the steering wheel effort. < Refer to MEASUREMENT OF STEERING EFFORT , INSPECTION, General Diagnostic Table. >

Adjust or replace.

Vehicle leads to one side or the other.
Returning force of steering wheel to center is poor.
Steering wheel vibrates when turning.

1. Tire and wheel

Flat tire
Mixed use of different tires
Mixed use of different wheels
Abnormal wear of tire
Unequal tread remaining
Unequal pressure of tire

Adjust, fix or replace.

2. Front alignment

Improper or unequal caster
Improper or unequal toe-in
Loose suspension connections

Adjust or retighten.

3. Others

Damaged joint assembly
Unbalance of ground clearance
Unbalance of load

Replace, adjust or instruct customer.

4. Measure the steering wheel effort. < Refer to MEASUREMENT OF STEERING EFFORT , INSPECTION, General Diagnostic Table. >

Adjust or replace.

⁽¹⁾

If the tires or wheels are wider than standard, the load to power steering system is increased. Accordingly, in a condition, for example before fluid warms-up, relief valve may work before reaching maximum turning angle. In this case, steering effort may be heavy. When the 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 the steering wheel from stop to stop several times to warm up fluid. If steering effort reduces normally, function is normal.

⁽³⁾	In cold weather or with insufficient warm up of the engine, steering effort may be heavy due to excessive drop of idling when turning the steering wheel. In this case, start the vehicle with increasing engine speed than usual. If steering effort reduces normally, function is normal.