General Diagnostic Table: Inspection: Notes

Hydraulic type

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. 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.

2. 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. Instruct customers.

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. 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.

5. Measure the hydraulic Pressure. Refer to POWER ASSISTED SYSTEM (POWER STEERING)>OIL PUMP>INSPECTION .

Replace the faulty parts.

6. Measure the steering wheel effort. Refer to POWER ASSISTED SYSTEM (POWER STEERING)>GENERAL DIAGNOSTIC TABLE>INSPECTION>MEASUREMENT OF STEERING EFFORT (HYDRAULIC TYPE) .

Adjust or replace.

7. Fluid line

Fluid leakage from fluid line

Repair 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, repair or replace the tire and wheel.

2. Front wheel 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 or adjust the faulty parts, or instruct customer.

4. Measure the steering wheel effort. Refer to POWER ASSISTED SYSTEM (POWER STEERING)>GENERAL DIAGNOSTIC TABLE>INSPECTION>MEASUREMENT OF STEERING EFFORT (HYDRAULIC TYPE) .

Adjust or replace the faulty parts.

⁽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 situation, steering effort may become relatively 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. Start the vehicle with increasing engine speed than usual. If the steering effort returns to normal, the function operates normally.

Electric type

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 Improper wheel out of specification Tires not properly inflated	Replace or reinflate the tire and wheel.
	2. Measure the steering wheel effort. Refer to POWER ASSISTED SYSTEM (POWER STEERING)>GENERAL DIAGNOSTIC TABLE>INSPECTION>MEASUREMENT OF STEERING EFFORT (ELECTRIC TYPE) .	Adjust or replace the faulty parts.
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, repair or replace the tire and wheel.
	2. Front wheel alignment Improper or unequal caster Improper or unequal toe-in Loose suspension connections	Adjust or retighten.
	3. Measure the steering wheel effort. Refer to POWER ASSISTED SYSTEM (POWER STEERING)>GENERAL DIAGNOSTIC TABLE>INSPECTION>MEASUREMENT OF STEERING EFFORT (ELECTRIC TYPE) .	Adjust or replace the faulty parts.

NOTE: When performing repeated steering operation with the vehicle at standstill, the steering effort may be temporarily heavy because the heat generated in the system activates the power steering protection control. This is not a malfunction caused by the steering system. After a while, it will return to normal steering effort. (In this case, the steering warning light will not come on and there will be no DTC.)