The steering torque sensor in your 2020 Subaru Forester measures how much force you're applying to the steering wheel, telling the EPS system how much assist to provide. When this sensor fails, the EPS system cannot properly assist your steering effort.
Torque Sensor Function
The torque sensor measures the twist force you apply to the steering column. This input tells the EPS control module how hard you're trying to turn—allowing proportional assist that feels natural. Without torque data, the system can't know how much help you need.
Failure Symptoms
Torque sensor failure typically causes EPS warning lights and may result in loss of power assist, erratic assist that doesn't match your effort, or the system defaulting to a fixed assist level. Steering remains mechanically functional but effort increases significantly.
Sensor Construction
Torque sensors typically use strain gauges or magnetic sensors to measure steering column twist. The sensor is integrated into the steering column assembly and requires proper calibration to function correctly.
Causes of Failure
Torque sensors can fail from internal electronic issues, physical damage, water intrusion, or wiring problems. Some failures are intermittent before becoming permanent. Heat cycling and age contribute to gradual degradation.
Replacement Considerations
Torque sensor replacement often involves significant steering column disassembly. The new sensor requires calibration after installation. This is typically not a DIY repair due to complexity and the need for calibration equipment.
Code C0051 Analysis
Code C0051 relates to torque sensor circuit issues. This code indicates the EPS system has detected abnormal torque sensor signals—either no signal, out-of-range values, or erratic readings.