Description and Operation

Description

The EPS (electric power steering) system uses an electric motor to assist steering effort and does not depend on the engine. The EPS control module controls the motor operation according to information received from each sensor and the CAN (controller area network), resulting in more precise power steering control than hydraulic systems driven by the engine. The EPS system components (torque sensor, fail-safe relay, etc.) are located inside the steering column and the EPS unit and cannot be disassembled for inspection or replacement.

Operation

Diagnostic Note

Failure rate	Inspection item	Symptom	EXPLANATION	Noticed
Drop, Impact and Overload	Engine	Abnormal Noise	Visible or invisible damage may be present. The wheel may pull to one side due to fallen debris. Some engine/control unit parts are sensitive to vibration and impact. Overloading may cause unexpected damage.	Do not use a damaged EPS. Do not overload the parts.
	ECU	Damaged circuit Poor solder joint Printed circuit board broken Damaged parts
	TORQUE SENSOR	Insufficient steering effort	Overloading the input shaft may cause torque sensor malfunction.	Do not strike the connecting parts (when inserting and torquing). Use the special tool to remove the power steering. (Do not press on it.) Do not use a damaged EPS.
	WOOD	Insufficient steering wheel effort (imbalance between left and right turns)		Do not use a damaged EPS.
pull / push	Beam	Failure - electrical operation not possible EPS malfunction	Harness disconnected or incorrectly connected	Do not overload the beam
Abnormal storage temperature	Engine / ECU	Abnormal steering wheel effort due to incorrect engine/ECU operation	Wire in normal condition Even slight mold may cause some engine / ECU parts to malfunction	Ensure correct storage temperature and humidity Do not submerge