EPS Electric Power Steering

EPS Electric Power Steering system diagram.

Electric power steering systems use a reversible electric motor to assist in steering effort instead of hydraulic fluid. A control module receives information from sensors like the steering torque, angle, and speed sensors to control the voltage and direction of current sent to the motor.

When the vehicle is traveling slowly or negotiating parking maneuvers more voltage is needed to assist steering effort. As the vehicle travels faster less assist is required and less voltage is needed. This provides more assist to the driver while parking and better road feel at highway speeds.

If a problem occurs, a warning light is illuminated and a scan is in order. Always inspect the basic steering system and the associated circuit before replacing electronic components. Trouble codes are typically manufacturer specific and will point the technician to the problem area. Depending on the manufacturer, the sensors can be tested with an ohmmeter or with the scan tool. Motor operation is bidirectional and the system protected by a fuse.

The motor may be attached to the steering column, under the instrument panel, or on the rack. Sometimes the sensors are part of the unit and some disassembly is required. Due to advances in technology these steering systems are becoming more and more popular with vehicle manufactures.