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Home >> Buick >> 2018 >> Regal Base >> Repair and Diagnosis >> Brakes >> Traction Control >> Antilock Brake System >> Diagnostic Information and Procedures >> DTC C0121 >> Circuit/System Description
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Circuit/System Description

The valve relay is an integral part of the electronic brake control module (EBCM), while the solenoid valves are integral to the brake pressure modulator valve assembly. The valve relay is engaged during normal system operation and provides voltage to the solenoid valves. When the ABS control operation is required, the EBCM controls the solenoid valves by providing ground to the active solenoid valves.