How to Bleed ABS Brakes with Scan Tool? | 3-Stage Method

Bleeding ABS brakes with a scan tool uses a three-stage process: manual pre-bleed, scan-tool cycling, then final manual bleed to purge trapped air from the module.

Knowing how to bleed ABS brakes with a scan tool is the difference between a firm pedal and one that stays spongy no matter how many times you pump. Standard bleeding clears the lines but cannot reach air trapped inside the ABS modulator — a bi-directional scanner is required to cycle the pump and valves, forcing that air out where a final manual bleed clears it. This walkthrough covers the exact three-stage sequence.

Why Do You Need a Scan Tool to Bleed ABS Brakes?

The ABS modulator sits between the master cylinder and the wheel calipers. Air bubbles get trapped in its internal valves and passages during a fluid change or repair. A standard two-person bleed only moves fluid through the lines — it cannot trigger the ABS pump or open the solenoid valves inside the module. Without a scan tool running an ABS Bleeding or Auto Bleed function, that air stays put and the pedal stays soft. The module must also be programmed by the manufacturer to support an automated bleed cycle; not every vehicle has this capability.

Tools You’ll Need for Bleeding ABS Brakes With a Scan Tool

The XTOOL A30M pairs via Bluetooth with the Anyscan app on iOS or Android and accesses the ABS bleed function under Special Functions. Beyond the scan tool, gather fresh brake fluid, a bleeder wrench, clear tubing, a catch container, rags, and safety goggles. If you’re shopping for a scanner, our roundup of the best ABS brake bleeding scan tools compares the top options side by side.

Set the parking brake on level ground, chock the wheels, and clean each bleeder screw before starting. Keep the master cylinder topped off through the entire job — letting it run dry pulls fresh air into the system and forces a full restart.

The 3-Stage ABS Brake Bleeding Process

Stage 1: Manual Pre-Bleed

The manual pre-bleed clears the brake lines so the scan tool’s cycle actually works. Bleed the wheels in this order: rear passenger, rear driver, front passenger, front driver. With a helper pressing the brake pedal, open each bleeder briefly, then close it before the pedal is released. Repeat at each wheel until fluid runs clear with no air bubbles. Skipping this stage means the scan tool cannot purge the module effectively.

Stage 2: Scan Tool ABS Module Cycling

Connect the scan tool to the OBD-II port and pair it via Bluetooth if using the XTOOL A30M. With the ignition on and engine off, navigate to Special Functions → ABS Bleeding. Follow the on-screen prompts — the tool will cycle the ABS pump and open the solenoid valves in sequence (typically left front, right front, left rear, right rear). Run the cycle as many times as the app instructs until it confirms all air is purged from the module.

Stage 3: Final Manual Bleed

The scan tool pushes trapped air out of the ABS module and into the brake lines, but that air still needs to exit through the bleeders. Immediately after the scan tool cycle, manually bleed all four wheels again in the same order as Stage 1. Test the brake pedal — it should feel solid, not spongy. Take a slow test drive in a safe area before returning to normal driving.

Common Mistakes to Avoid

• Letting the reservoir run dry during any stage — this introduces new air and requires restarting the entire procedure.
• Releasing the brake pedal before closing the bleeder — this sucks air back into the system through the bleeder threads.
• Skipping the manual pre-bleed — the scan tool cannot purge air if the lines are still full of bubbles.
• Omitting the final manual bleed — air forced out of the module stays in the lines unless you bleed it out.
• Pushing the pedal to the floor during bleeding — this can damage older master cylinders internally.

The three-stage sequence — manual pre-bleed, scan tool cycle, and final bleed — is the only method that removes air from the entire system, including the modulator.