Possible causes

– Faulty Rear Speed Sensor
– Rear Speed Sensor harness is open or shorted
– Rear Speed Sensor circuit poor electrical connection
– Faulty EBCM

Symptoms

– ABS Warning Light ON

C0235 BUICK Description

As the wheel spins, the wheel speed sensor produces an Alternating Current (AC) signal. The Electronic Brake Control Module (EBCM) uses the frequency of the AC signal to calculate the wheel speed.