C0638 Code: Meaning, Causes, and Symptoms | OBD2 Codes

C0638 – Left Front Normal Force Circuit High


C0638 Possible Symptoms


Anti-Lock Brake System (ABS) Warning Light ON,Engine Light ON (or Service Engine Soon Warning Light)


C0638 Possible Causes


Faulty Electronic Brake Control module (EBCM),Electronic Brake Control module (EBCM) harness is open or shorted,Electronic Brake Control module (EBCM) circuit poor electrical connection


C0638 Description


The Continuously Variable Road Sensing Suspension (CVRSS) module estimates the road surface and communicates that information to the Electronic Brake Control module (EBCM). The CVRSS module provides a Pulse Width Modulation (PWM) signal to the EBCM through the left and right normal force signal circuits. The CVRSS module sends each normal force value twice to the EBCM. The possible values of the PWM duty cycle are 20%, 40%, 60% and 80%, with the valid range from 10-90%. The EBCM uses this information to provide improved rough-road braking performance.