What Does C1938 Mean?
The stability control module has detected an unrecognized or invalid identification code from the steering wheel angle sensor, indicating a communication or configuration mismatch. This typically occurs when a replacement sensor is not properly initialized or when there is a CAN bus communication error between the sensor and the ESC module. The driver will see the stability control warning light and these safety systems will be disabled.
Common Causes
35%
Replacement steering angle sensor not programmed or initialized to the vehicle
25%
Incompatible or incorrect part number steering angle sensor installed
20%
CAN bus communication fault between the sensor and the ESC module
15%
Corrupted sensor firmware or internal EEPROM failure
5%
ESC module software requires update to recognize the sensor variant
Diagnostic Steps
1
Verify the steering angle sensor part number matches the OEM specification for this vehicle's year, make, model, and option package. Cross-reference against the service manual.
2
Attempt to initialize/register the sensor to the vehicle using the scan tool's module configuration or setup function. Follow the manufacturer's specific initialization procedure.
3
Monitor CAN bus communication using the scan tool — verify the steering angle sensor is transmitting valid messages on the correct CAN bus (typically the chassis CAN). Check for missing or malformed frames.
4
If the sensor was recently replaced, confirm the clock spring and connector are properly seated. Check for bent pins or corrosion at the connector.
5
If the sensor is OEM and was not recently replaced, perform a module reset on the ESC controller and re-attempt sensor ID learning. Check for TSBs regarding software updates for the ESC module.
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The stability control module has detected an unrecognized or invalid identification code from the steering wheel angle sensor, indicating a communication or configuration mismatch. This typically occurs when a replacement sensor is not properly initialized or when there is a CAN bus communication er...
The most common cause of C1938 (Invalid Steering Wheel Angle Sensor ID) is: Replacement steering angle sensor not programmed or initialized to the vehicle
Typical repair costs for C1938 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle is drivable, but stability control, traction control, and potentially ABS advanced features are disabled. Drive cautiously, especially in adverse weather conditions. Schedule repair promptly as these are critical safety systems.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1938 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Chassis
System
Stability Control / Steering
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
