ABS and Brake Light come on and off.....

1997 blazer .a.s.b. light comes on and off while driving.what causes this and is it serious?

Fault code C0265 suggests an internal fault with the Electronic Brake Control Module on your 2001 Chevrolet Blazer. A shorted ABS pump motor can damage the Control Module causing this code to set. A resistance check must be done on the pump motor before replacing the Electronic Brake Control Module (EBCM) to avoid possible damage to the new part. If a new EBCM is installed is will need to be calibrated to the correct tire size using a scan tool which is capable of doing so.