C1938: Invalid Steering Wheel Angle Sensor ID

What does C1938 mean?

C1938 is a diagnostic trouble code indicating "Invalid Steering Wheel Angle Sensor ID". A sensor in the steering is reporting abnormal data or has lost communication with the ECU. Sensors can fail due to age, contamination, heat exposure, or wiring issues.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Intermittent warning lights
• Erratic gauge readings

Common causes

• Faulty steering component
• Wiring or connector issue in the related circuit
• Failed sensor providing incorrect readings
• Software/calibration issue requiring ECU update
• Related component causing secondary fault

What should you do?

This code sits in the steering system. Power assistance can cut out without warning, which makes the wheel go heavy, usually worst at parking and low speeds. Steering itself does not disappear, but the effort changes suddenly. Get it diagnosed before driving.