Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Possible Causes
2021 Ford Edge SE, 4WDSECTION Possible Causes
WARNING: This page is about a different car, the 2019 Ford F-550 Super Duty, 2019 Ford F-450 Super Duty, 2019 Ford F-350 Super Duty, and 2019 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
- Incorrect sensor input
- Stuck valve
- ABS module
- ABS module and HCU assembly
Harness Side
- Y1: GUIDED DIAGNOSTIC QUESTION
- This step is for vehicles equipped with EPB system or an electric brake booster.
- Were you sent here from diagnostics in the Parking Brake Actuation article or the Power Brake Actuation article?
Yes No Go to Y5. Go to Y3. - Y2: RECHECK THE ABS MODULE FOR DTCS
- Ignition ON, engine OFF.
- Clear the ABS DTCs.
- Ignition OFF.NOTE: If DTC U2007:4B or U3000:4B is present, allow the vehicle to cool for 30 minutes.
- Ignition ON, engine OFF.
Carry out the ABS self-test.
- Record the ABS module DTCs.
- Are any of the DTCs from the Fault Trigger Conditions table present and active in the ABS module?
Yes No Go to Y6. Go to Y4. - Y3: RECHECK THE ABS MODULE FOR DTCS
- Ignition ON, engine OFF.
- Clear the ABS DTCs.
- Ignition OFF.NOTE: If DTC U2007:4B or U3000:4B is present, allow the vehicle to cool for 30 minutes.
- Ignition ON, engine OFF.
Carry out the ABS self-test.
- Record the ABS module DTCs.
- Are any of the DTCs from the Fault Trigger Conditions table present and active in the ABS module?
Yes No Go to Y5. Go to Y4. - Y4: VERIFY THE ABS MODULE TO HCU FASTENERS
- Ignition OFF.
- Verify all ABS module-to-HCU fasteners are tightened to their correct torque specifications. Refer to the Anti-Lock Brake System (ABS) and Stability Control article.
- Are fasteners tightened to their correct torque specifications?
Yes No Go to Y5. TIGHTEN all ABS module fasteners to their correct torque specifications.
Go to Y5. - Y5: CHECK FOR CORRECT ABS MODULE OPERATION
- Ignition OFF.
- ABS Module connector disconnected. (C135)
- Using a good light source, inspect the electrical connector for the following:
- corrosion - install new connector or terminal and clean the module pins
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary
- spread terminals - install new terminals as necessary
- ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes No INSTALL a new ABS module.
CHECK OASIS for any service articles: TSB, GSB, SSM or FSA.
If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions.
If no service articles address this concern, INSTALL a new ABS module. REFER to the Anti-Lock Brake System (ABS) and Stability Control article.
ORDER a replacement ABS module and INCLUDE the RVC on the form.
If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues. - Y6: CHECK FOR CORRECT ABS OPERATION
- Ignition OFF.
- ABS Module connector disconnected. (C135)
- Using a good light source, inspect the electrical connector for the following:
- corrosion - install new connector or terminal and clean the module pins
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary
- spread terminals - install new terminals as necessary
- ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes No INSTALL a new HCU.
CHECK OASIS for any service articles: TSB, GSB, SSM or FSA.
If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions.
If no service articles address this concern, INSTALL a new ABS module and HCU assembly. REFER to the Anti-Lock Brake System (ABS) and Stability Control article.
ORDER a replacement ABS module and HCU assembly. INCLUDE the RVC on the form.
If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.