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How to Replace an ABS Control Module

typical abs unit

An ABS module actually consists of three components — the electrical module with electrical solenoids, the brake line block, and the pump motor that builds pressures in the brake lines to be used during ABS braking situations.

Replacing an ABS module can be a daunting procedure. This module is a menacing looking device with warnings displayed all over it. There are high pressures in the brake lines that should be respected if you find you have to remove them.

  • Note: Not all ABS modules require the brake lines to be removed. This depends on the manufacturer of the car you are working on. Other than the removal of the brake lines, the procedures for replacing an ABS module are virtually the same.

The ABS module will need to be programmed once everything is installed. This procedure also will vary quite a bit depending on the manufacturer.

  • Tip: For this step in the ABS module replacement procedure, refer to the manufacturer's instructions to find the specific programming procedure.

Sometimes, the module will be replaced along with the solenoid block and other times it will not. This is dependent on the design and location of the ABS unit which is based on the manufacturer’s design, build choices, and how the replacement module is sold.

Part 1 of 6: Locate the ABS module

Materials Needed

every vehicle will involve a different process for removing

Step 1: Refer to your specific repair manual to locate the ABS module. Usually, the repair manual will have a drawing with an arrow pointing at the area where the module is mounted.

At times, there will also be a written description that can be very useful.

  • Tip: The ABS module has many metal brake lines connected to it. The module itself is bolted to the solenoid block and will need to be separated from it. This isn’t always the case as some manufacturers will require the module and the solenoid block to be replaced simultaneously.

Step 2: Find and identify the module on the car. You may need to lift the vehicle and remove some plastic covers, panels or other components to locate the ABS module.

  • Note: Remember the ABS module will be bolted to a solenoid block that has many brake lines connected to it.

Part 2 of 6: Determine how to remove the ABS unit from the car

Step 1: Refer to the manufacturer’s repair instructions. You may be able to remove the ABS module from the vehicle as a complete unit or remove only the electrical module while the solenoid block remains attached to the vehicle.

  • Tip: On some vehicles, you can get away with removing the module from the solenoid block while the solenoid block is still bolted to the car. Other vehicles may require the two components to be replaced as a unit. This is dependent on how well you can access it and how the new module is sold.

the complete abs unit with motor module and solenoid block

Step 2: Move onto part 3 or part 4. Skip to part 4 if you only need to remove the module and not the solenoid block and motor. If the ABS module, solenoid block, and the motor will be removed as a complete unit, move onto part 3.

Part 3 of 6: Remove the module and solenoid block as a unit

Step 1: Release brake line pressure. Some vehicle will have high pressure contained within the ABS unit. If this is the case with your vehicle, refer to the specific repair manual for your car to determine the correct methods for releasing the line pressure.

Step 2: Disconnect the electrical connector from the module. The connector will be large and have a retaining mechanism.

Each manufacturer uses different mechanisms to retain connectors.

  • Tip: Be sure to mark the lines before removing them to ensure that you can reconnect them in their original positions.

Step 3: Remove the brake lines from the module. You will need the appropriate size line wrench to remove the lines without rounding them.

Once you have completely unthreaded all the lines from the block, pull up on them to remove them.

Step 4: Remove the ABS module with the solenoid block. Unbolt whatever bracket or bolts are used to mount the ABS module and solenoid block to the car.

This configuration will greatly depend on the make and model of car you are working on.

Step 5: Remove the ABS module from the solenoid block. Remove the bolts that attach the module to the solenoid block. Gently pry the module from the block.

This may require the use of a flat head screwdriver. Be sure to be gentle and patient.

  • Note: The removal of the module from the solenoid block is not always necessary as it depends on how the new unit is supplied to you. Sometimes, it is sold as a complete unit with solenoid block, module, and motor. Other times, it will be just the module.

Step 6: Skip to part 6. Skip part 4 as it is for module replacement that doesn’t require the removal of the solenoid block and brake lines.

Part 4 of 6: Remove only the module

backside of the module

Step 1: Disconnect the electrical connector from the module. The connector will be large and have a retaining mechanism.

Each manufacturer uses different mechanisms to retain this connector.

Step 2: Remove the module. Remove the bolts that attach the module to the solenoid block. Gently pry the module from the block.

This may require the use of a flat head screwdriver. Be sure to be gentle and patient.

Part 5 of 6: Install the new ABS module

Step 1: Install the module onto the solenoid block. Gently guide the module onto the solenoid block.

Do not force it, if it isn’t sliding on smoothly, remove it and take a close look at what is going on.

Step 2: Start threading the bolts by hand. Before tightening any of the bolts, start threading them by hand. Ensure that they are snug before applying the final torque.

Step 3: Connect the electrical connector. Push the electrical connector on. Use the locking mechanism to firmly attach and secure it to the module.

Step 4: Program the new module to the car. This procedure is dependent on the manufacturer of your vehicle and often isn’t necessary.

Refer to your manufacturer’s repair manual for the instructions to program this module.

Part 6 of 6: Install the ABS unit onto the car

Step 1: Install the module to the solenoid block. This step is only necessary if the new module is supplied separately from the solenoid block.

installation of the abs unit

Step 2: Install the ABS unit onto the car. Bolt the unit to the car as necessary.

Be sure to consider the alignment of the brake lines.

Step 3: Start the threads of the brake lines. Cross threading of the brake lines is a very real possibility that can lead to major problems.

Be sure to gently start each brake line by hand before using a wrench or applying the final torque.

Step 4: Torque all the brake lines. Make sure all the brake lines are tight and the flare end is firmly seated as you tighten the brake lines. Sometimes, this can be an issue. If it is, you will need to remove the leaking brake line and take a closer look at the flared end.

Step 5: Connect the electrical connector. Push the electrical connector on. Use the locking mechanism to firmly attach and secure it to the module.

Step 6: Program the new module to the car. This procedure will be dependent on the manufacturer of your vehicle and often isn’t necessary.

You will need to refer to your manufacturer’s repair manual to find the instructions for this process.

bleeding the brake lines

Step 7: Bleed the brake lines. Most of the time, you can bleed the brake lines at the wheels.

Some vehicles will have elaborate bleeding procedures that will need to be followed. Refer to your manufacturer’s repair manual for specific instructions.

Replacing an ABS module is a varied repair — on some vehicles, it can be very straightforward and simple while it is arduous and complicated on others. The complications can occur in the programming to the vehicle, the bleeding procedures, or the installation in cases where all the brake lines need to be removed.

Sometimes, the module is mounted in spots that require the removal of other components in order to access the ABS unit. Since brake systems span from the front to the rear of the car and on both sides, an ABS unit can be installed almost anywhere on a car. If you're lucky, it will be easily accessible and you will need to replace only the electrical portion of the ABS unit instead of having to do extensive disassembly, programming, and bleeding.

If your ABS light is on, you should always begin with a thorough diagnosis of the ABS system before replacing the ABS unit as ABS modules are expensive and complicated. Get a certified technician from YourMechanic to perform an inspection and diagnose the problem.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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