The EBCM supplies current to the variable effort steering actuator in both directions through the VES control circuits. With the vehicle at low speeds, the EBCM will supply current through the VES low control circuit and the scan tool will a display negative current value. The negative current value indicates positive steering assist. As the vehicle speed increases, the amount of current supplied will decrease towards zero. The zero current indicates no steering assist and the vehicle has normal power steering. As the vehicle speed continues to increase, the EBCM will supply current through the VES high control circuit and the scan tool will display a positive current value. The positive current value indicates negative steering assist, meaning the driver must supply more effort to turn the steering wheel.

The EBCM also detects the amount of current feedback through the actuator. By comparing the supplied current to the feedback current, the EBCM can determine when there is a fault in the circuit. If an open or short is present in the VES control circuits, the EBCM will set DTC C1241 Variable Effort Steering Circuit Malfunction. When DTC C1241 sets, the DIC displays the SERVICE STEERING SYS message. With DTC C1241 set current, the scan tool will not control the variable effort steering function.

The electronic brake control module (EBCM) defines a drive cycle as the completion of the EBCM initialization sequence. The EBCM performs the initialization sequence once each ignition cycle. Refer to Initialization Sequence in Antilock Brake System.