What is the correct procedure for bleeding an ABS brake system after replacing the hydraulic control modulator block?

1. Use a pressure bleeder and activate the modulator solenoid valves using a diagnostic scan tool during the bleeding process
2. Bleed the brakes using the traditional pump-and-hold method while leaving the ignition switch off
3. Bleed only the front calipers, as the rear brakes do not route through the ABS modulator assembly
4. Fill the master cylinder with water and flush it through the system until the fluid runs clean