Description and Operation

Description

The EPS (Electric Power Steering) system uses an electric motor to assist steering effort, and it operates independently of the engine. The EPS control module controls motor operation based on information received from each sensor and the CAN (Controller Area Network), providing more precise and timely steering assist than conventional engine-driven hydraulic systems. EPS system components (torque sensor, safety relay, etc.) are located inside the steering column and EPS unit. The steering column and EPS unit must not be disassembled for inspection or replacement.

Operation

Note Regarding Diagnosis

Problem Factor	Check Item	Symptom of Malfunction	Description	NOTE
Drop, Impact and Overload	Motor	Abnormal Noise	Visible or invisible damage may occur. The steering wheel may pull to one side due to dropped parts. Precision engine/ECU parts are sensitive to vibration and impact. Overloading may cause unexpected damage.	Do not use a damaged EPS. Do not overload any component.
	ECU	Circuit damage Incorrect welding point Broken printed circuit board Damaged precision parts
	Torque Sensor	Insufficient steering effort	Overloading the INPUT shaft may cause torque sensor malfunction.	Do not strike connecting parts (when inserting and tightening). Use the specified tool to remove the steering wheel. (Do not strike it.) Do not use a damaged EPS.
	Shaft	Insufficient steering wheel effort (uneven between left and right sides)		Do not use a damaged EPS.
Pull / Dent	Restrain	Malfunction - power supply not possible EPS malfunction	Disconnection between the connector part and the harness	Do not overload the suspension.
Abnormal storage temperature	Engine / ECU	Abnormal steering effort due to incorrect engine/ECU operation	Waterproof under normal conditions Even a small amount of moisture may cause malfunction of precision engine/ECU parts.	Maintain normal temperature and proper humidity during storage. Avoid immersion in water.

R-MDPS Operating Mechanism