Performing an ABS brake bleed is a crucial maintenance task that ensures your vehicle’s braking system is functioning optimally. Traditionally, this procedure might require expensive professional tools or a trip to the mechanic. However, with the advent of Bluetooth OBDII scanners and user-friendly apps like JScan, DIY enthusiasts can now tackle this job at home. This guide will walk you through the process of ABS brake bleeding using a Bluetooth OBDII scanner, presenting it as a viable and cost-effective alternative to more expensive “superchips” or professional diagnostic tools.
Bleeding your ABS brake module is necessary when you’ve introduced air into the system, such as during brake line repairs, master cylinder replacement, or even after a standard brake bleed if the pedal still feels spongy. Air in the ABS module can significantly compromise braking performance, making it essential to remove it.
This guide is based on using the JScan app, a popular choice for Jeep vehicles, but the general principles apply to other vehicles and OBDII apps that offer ABS bleed functions. Keep in mind that this procedure ideally requires two people: one to operate the OBDII app and tools, and another to assist with the brake pedal.
Understanding ABS Brake Bleeding and Why It’s Necessary
The Anti-lock Braking System (ABS) is a vital safety feature in modern vehicles. It prevents wheel lock-up during hard braking, allowing you to maintain steering control. The ABS module contains hydraulic components and valves that can trap air during brake system maintenance. Regular brake bleeding may not always remove air from the ABS module, necessitating a specific ABS bleed procedure.
A spongy brake pedal is a key indicator of air in the brake lines, including the ABS module. If you’ve bled your brakes in the traditional way and the pedal still feels soft, an ABS bleed is likely needed. This procedure cycles the ABS pump and valves to push trapped air out through the bleed screws.
Tools You’ll Need: A Bluetooth OBDII Scanner Approach
For this DIY ABS brake bleed, you’ll need the following:
- Bluetooth OBDII Scanner: This is your “superchips alternative.” A quality Bluetooth OBDII scanner, compatible with your vehicle, is essential. These scanners wirelessly connect to your smartphone or tablet and communicate with your vehicle’s computer system.
- OBDII App with ABS Bleed Function: Apps like JScan (for Jeep/Chrysler/Dodge/RAM), AlfaOBD (for Fiat/Chrysler/etc.), and others offer advanced diagnostic and service functions, including ABS bleeding. Ensure the app you choose is compatible with your vehicle and OBDII scanner.
- Brake Bleeder Kit: A brake bleeder kit with a clear hose and catch bottle makes the process cleaner and allows you to easily see air bubbles exiting the system.
- Wrenches: You’ll need wrenches to open and close the bleeder valves on your brake calipers. Common sizes are 10mm and 11mm, but check your vehicle’s specifications.
- Fresh Brake Fluid: Use the correct type of brake fluid for your vehicle (DOT 3, DOT 4, etc.). Always use new, unopened brake fluid.
- Assistant: As mentioned, having someone to help with the brake pedal is highly recommended for safety and efficiency.
This setup, centered around a Bluetooth OBDII scanner and a smartphone app, provides a powerful yet affordable alternative to expensive professional scan tools or “superchips” designed for similar diagnostic and maintenance tasks.
Step-by-Step Guide to ABS Brake Bleeding with JScan
Preparation:
- Park on Level Ground: Ensure your vehicle is parked on a level surface and is safely secured with the parking brake.
- Gather Your Tools and Materials: Have everything within easy reach before starting.
- Check Brake Fluid Level: Ensure your brake fluid reservoir is filled to the maximum line.
- Connect OBDII Scanner: Plug your Bluetooth OBDII scanner into your vehicle’s OBDII port.
- Launch JScan App and Connect: Open the JScan app on your smartphone or tablet and connect to your vehicle using the Bluetooth OBDII scanner.
ABS Bleed Procedure:
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Navigate to Adaptation Menu: In the JScan app, select the “Adaptation” tab.
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Select Vehicle Maintenance: Scroll down in the Adaptation menu and select “Vehicle Maintenance.”
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Choose ABS Brake Pump Bleed: From the Vehicle Maintenance menu, select “ABS Brake Pump Bleed.”
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Read Warning Messages and Proceed: JScan will display several warning messages. Read them carefully, ensuring you understand the instructions and safety precautions. Press “Go” to proceed through each warning. These warnings typically cover safety measures like ensuring the vehicle is on level ground and that you’ve already performed a standard brake bleed.
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Prepare Brake Pedal: Instruct your assistant to be ready to press and hold the brake pedal. If the pedal is soft, have them pump it firmly 3-5 times to build pressure and then hold it down firmly.
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Start ABS Bleed Procedure: Press “Go” in the JScan app to initiate the ABS bleed procedure.
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ABS Module Activation: The ABS module will activate, and your assistant will feel the brake pedal pushing upwards as the module pumps. This pumping action will occur several times in short bursts. This pumping action is a good sign that the electronic and mechanical components of your ABS module are functioning.
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Prepare to Bleed Front Driver’s Side Caliper: JScan will instruct you to move to the front driver’s side brake. Locate the bleeder valve and have your 11mm wrench ready. Do not open the bleeder valve yet.
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Initiate Bleeding – Front Driver’s Side: Press “Go” in the JScan app. JScan will display a “Test in Progress” screen, but no test is actively running yet. This is your cue to get your wrench on the bleeder valve and prepare to open it.
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Open Bleeder Valve During ABS Pump: Press “Go” again. JScan will activate the ABS module, initiating a series of 4 pump cycles. Crucially, wait for the second pump cycle to begin, then crack open the bleeder valve about half a turn.
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Observe and Close Bleeder Valve: Leave the bleeder valve open during the remaining pump cycles (cycles 2, 3, and 4). Watch the clear hose of your brake bleeder kit for air bubbles exiting with the brake fluid. After the 4th pump cycle completes and JScan displays the “Close the front Bleeder Valve” screen, immediately close the bleeder valve.
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Move to Rear Driver’s Side Caliper: Press “Go” in JScan. Gather your brake bleeder tool and 10mm wrench and move to the rear driver’s side wheel. Instruct your assistant to continue holding the brake pedal.
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Repeat Bleeding – Rear Driver’s Side: JScan will again display a “Test in Progress” screen after you press “Go.” Prepare your 10mm wrench on the rear bleeder valve, but do not open it yet. Press “Go” again.
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Open Bleeder Valve During ABS Pump – Rear: JScan will activate the ABS module for another 4 pump cycles. This time, wait for the 3rd pump cycle to begin, then crack open the rear bleeder valve about half a turn.
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Observe and Close Bleeder Valve – Rear: Leave the bleeder valve open during the remaining pump cycles (cycles 3 and 4). Observe for air bubbles. After the 4th pump, when JScan displays the “Close the Rear Bleeder Valve” screen, immediately close the bleeder valve.
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Complete Procedure: Press “Go” on the “Close the Rear Bleeder Valve” screen. JScan will display “ABS Module Bleed Complete!”
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Repeat for Passenger Side: The procedure isn’t finished yet! You need to repeat steps 8-16 for both the front and rear passenger side brakes, following the same instructions and valve opening timing.
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Top Off Brake Fluid: After completing all four wheels, top off your brake fluid reservoir to just above the maximum line.
Important Tips and Troubleshooting
- Brake Fluid Level: Monitor the brake fluid reservoir level throughout the procedure and ensure it doesn’t drop too low. Refill as needed to prevent air from being drawn back into the system.
- Communication Errors: If you encounter communication errors with the JScan app or OBDII scanner, ensure the scanner is properly plugged in, Bluetooth is enabled, and the app is correctly configured for your vehicle. Turning the vehicle ignition off and back on, and restarting the app, can sometimes resolve communication issues.
- Bleeder Valve Condition: Ensure your bleeder valves are not seized or corroded. If necessary, apply penetrating oil beforehand. Be careful not to break them.
- No Fluid Output: If you don’t observe fluid being pushed out of the bleeder valve during the ABS pump cycles, it could indicate a problem with the ABS module. However, double-check your procedure and connections before concluding the module is faulty.
- Two-Person Job: While possible to do alone with a brake pedal prop, it is strongly recommended to have an assistant for safety and to ensure consistent brake pedal pressure.
Conclusion
Performing an ABS brake bleed at home using a Bluetooth OBDII scanner and an app like JScan is a viable alternative to expensive professional services or specialized “superchips” tools. It empowers DIY mechanics to maintain their vehicle’s braking system effectively and affordably. By following these steps carefully and paying attention to detail, you can ensure your ABS system is properly bled, restoring optimal braking performance and safety. Remember to always prioritize safety and consult your vehicle’s service manual for specific recommendations and fluid types.
