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Home >> Lexus >> 2012 >> IS 250C Automatic Trans >> Repair and Diagnosis (Single Page) >> Steering >> Power Steering >> Power Steering System (Diagnostics - Introduction) >> Power Steering System >> Problem Symptoms Table >> Problem Symptoms Table
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Problem Symptoms Table

HINT: 

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

POWER STEERING SYSTEM

Symptom Suspected Area See
Steering is heavy Front tires (Improperly inflated, unevenly worn) Refer to INSPECTION - Step 1
Front wheel alignment (Incorrect) Refer to ADJUSTMENT
Front suspension (Lower ball joint) Refer to INSPECTION - Step 1
Power steering gear assembly Refer to REMOVAL
Steering column assembly Refer to REMOVAL
Torque sensor (Built into steering gear assembly) Refer to DTC C1511: Torque Sensor Circuit Malfunction; DTC C1512: Torque Sensor Circuit Malfunction; DTC C1513: Torque Sensor Circuit Malfunction
Power steering motor -
Speed sensor Refer to TEST MODE PROCEDURE
Skid control ECU -
Battery and power source system -
Power steering ECU power source voltage and relay Refer to DTC C1552: PIG Power Supply Voltage Malfunction; DTC C1554: Power Supply Relay Failure
Power steering ECU assembly Refer to REMOVAL
Steering effort differs between right and left or steering effort is uneven. Calibration of turning angle sensor output and torque sensor Refer to CALIBRATION 
Front tires (Improperly inflated, unevenly worn) Refer to INSPECTION - Step 1
Front wheel alignment (Incorrect) Refer to ADJUSTMENT
Front suspension (Lower ball joint) Refer to INSPECTION - Step 1
Power steering gear assembly Refer to REMOVAL
Torque sensor (Built into steering gear assembly) Refer to DTC C1511: Torque Sensor Circuit Malfunction; DTC C1512: Torque Sensor Circuit Malfunction; DTC C1513: Torque Sensor Circuit Malfunction
Steering column assembly Refer to REMOVAL
Power steering motor -
Power steering ECU assembly Refer to REMOVAL
While driving, steering effort does not change in accordance with vehicle speed or the steering wheel does not return properly. Front suspension (Lower ball joint) Refer to INSPECTION
Speed sensor Refer to TEST MODE PROCEDURE
Skid control ECU -
Combination meter Refer to REMOVAL
Torque sensor (Built into steering gear assembly) Refer to DTC C1511: Torque Sensor Circuit Malfunction; DTC C1512: Torque Sensor Circuit Malfunction; DTC C1513: Torque Sensor Circuit Malfunction
Power steering motor -
Power steering gear assembly Refer to REMOVAL
Power steering ECU assembly Refer to REMOVAL
A knocking (or cranking) sound occurs when turning the steering wheel back and forth while power steering is in operation. Front suspension (Lower ball joint) Refer to INSPECTION
Steering intermediate shaft -
Power steering gear assembly Refer to REMOVAL
Noise occurs when turning the steering wheel during low speed driving. Power steering gear assembly Refer to REMOVAL
Steering column assembly Refer to REMOVAL
Power steering ECU assembly Refer to REMOVAL
High-pitched sounds (squeaking) occur when turning the steering wheel slowly with the stepped. Power steering gear assembly Refer to REMOVAL
Power steering motor -
The steering wheel vibrates and noise occurs when turning the steering wheel from lock to lock. Power steering gear assembly Refer to REMOVAL
Steering column assembly Refer to REMOVAL
P/S warning light remains on. PS warning light remains on Refer to PS Warning Light Remains ON
P/S warning light does not come on. PS warning light does not come on Refer to PS Warning Light does not Come ON