Steering Wheel Angle Sensor Offset Failure
The steering wheel angle sensor has lost its calibration reference point, like a compass that no longer knows where north is. The vehicle's stability control system can't properly track steering input, potentially causing safety and handling issues.
The ECU continuously monitors the steering wheel angle sensor's zero-point offset during vehicle operation. When the vehicle is centered and traveling straight, the sensor should report a neutral position; if this baseline drifts beyond calibration limits, the offset fails. The system uses steering rate and vehicle yaw signals to validate the sensor's accuracy.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Steering Wheel Angle Offset | ±2 to ±5 degrees at center | Exceeds ±10 degrees or cannot self-calibrate |
| Sensor Signal Validity | Continuous, smooth signal correlation with yaw rate | Signal drift or loss of correlation with vehicle dynamics |
Code C1937 is classified as a serious fault. If your check engine light is flashing — not just steady — pull over safely and do not continue driving. A flashing CEL indicates an active misfire or critical failure that can cause catalytic converter damage within minutes or permanent engine harm within miles. Contact a certified mechanic immediately. Do not attempt roadside repairs on high-severity codes unless you are trained to do so.
Once the fault is repaired, C1937 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.