Why Your Expedition's ABS Light Is On (And How to Fix It)

How to Fix ABS Light

When the ABS light illuminates on your 2020 Ford Expedition, it signals a fault within the Anti-lock Braking System that requires immediate attention. While this warning light can be alarming, understanding the specific causes reported by owners of this model year is the first step to a resolution. The issue is often more straightforward than it seems, but ignoring it compromises a critical safety system. As one owner shared about their overall experience with the SUV: "One guy bought a 2020 and has put 100k miles on it and only done fluid, brakes, and tires to this point." This highlights that while these trucks can be reliable, brake system components, including those related to ABS, are expected wear items that will eventually need service.

Symptoms

The primary symptom is, of course, the persistent illumination of the ABS warning light on your instrument cluster. This yellow or orange light typically looks like the letters "ABS" inside a circle. Once this light is on, it indicates the vehicle's computer has detected a fault and has likely disabled the anti-lock braking function. You will still have normal hydraulic brakes, but you will lose the anti-lock feature that prevents wheel lock-up during hard stops, which can lead to longer stopping distances on slick surfaces.

Owners have reported correlating symptoms that often accompany or precede the ABS light. A common one is unusual noises related to the wheel areas, which house the ABS wheel speed sensors. You might hear a persistent buzzzzzing or a cyclic buffeting noise that changes with vehicle speed. These sounds can indicate a failing wheel bearing or a damaged tone ring that the ABS sensor reads. As the bearing deteriorates, it can cause the tone ring to wobble or the sensor gap to change, triggering a fault.

Another symptom is a physical bump or vibration felt through the brake pedal or steering wheel, especially during light braking. This can sometimes be mistaken for warped brake rotors, but on vehicles with stability control (which uses the ABS system), a faulty wheel speed sensor can cause the system to incorrectly apply brake pressure to a single wheel, creating a pulsing sensation. In more severe cases, you may experience a "bad day" where multiple warning lights illuminate simultaneously, such as the ABS light alongside the traction control or stability control lights, indicating a more central system failure.

Most Likely Cause

Based on analysis of owner reports and discussions, the most likely cause of an ABS light in the 2020 Ford Expedition is a failing wheel hub bearing assembly. This is an integrated unit that contains the wheel bearing and the crucial ABS tone ring (or reluctor ring). The Expedition is a heavy SUV, and these components are under significant stress. As one owner succinctly noted regarding common repairs: "Another had to do wheel hubs at around 90k miles which isn't crazy for a heavy SUV anyhow." This direct experience points to wheel hubs as a known wear item.

The failure mechanism is straightforward. The wheel hub assembly can wear out or become contaminated, leading to excessive play. This movement causes the integrated tone ring to wobble relative to the stationary ABS wheel speed sensor. The sensor then reads an inconsistent or implausible speed signal compared to the other wheels. When the ABS module receives this erratic data, it cannot reliably perform its function, so it triggers the warning light and deactivates the system. Corrosion or physical damage to the sensor itself, often caused by road debris or improper handling during other repairs, can also be the culprit, but the hub assembly is the primary failure point cited by owners.

How to Diagnose

Diagnosing an ABS light requires an OBD-II scanner capable of reading ABS-specific codes. A standard code reader for engine lights will not suffice. You need a scanner that can access the chassis or ABS module. Plug the scanner into the diagnostic port under the dashboard, turn the ignition to the "ON" position (engine off), and read the stored fault codes. Common codes for wheel speed sensors are typically labeled as "C" codes, such as C0035 (Front Left Wheel Speed Sensor) or C0040 (Front Right Wheel Speed Sensor). A code pointing to a specific corner of the vehicle is your strongest clue.

If you don't have an advanced scanner, you can perform a basic visual and physical inspection. Safely jack up the vehicle and support it with jack stands. Remove the wheel on the suspected corner (based on any correlating noise). Visually inspect the wheel speed sensor, which is mounted near the hub and has a wiring harness leading to it. Look for obvious damage to the wire, corrosion on the sensor connector, or signs that the sensor has been impacted. Check for play in the wheel bearing by gripping the tire at the 12 and 6 o'clock positions and rocking it in and out. Excessive movement indicates a bad wheel bearing/hub assembly.

For a more advanced check without a scanner, you can use a multimeter. Disconnect the electrical connector for the wheel speed sensor. Set your multimeter to measure resistance (Ohms). Probe the two terminals of the sensor itself (not the harness). A typical sensor should read between 1,000 and 2,500 Ohms. A reading of zero (short) or infinity (open) means the sensor is faulty. You can also check for AC voltage while slowly spinning the wheel by hand; a functioning sensor will generate a small alternating current.

Step-by-Step Fix

Replacing a faulty wheel hub bearing assembly is the most common repair. Here is a detailed guide for a front wheel hub replacement (the process is similar for the rear).

Step 1: Safety and Preparation. Park on a level surface, engage the parking brake, and chock the rear wheels. Loosen the lug nuts on the affected wheel slightly before lifting the vehicle. Safely jack up the front of the truck and support it with a quality jack stand placed on the frame. Remove the lug nuts and the wheel.

Step 2: Access the Hub. Remove the brake caliper and rotor to access the hub. Unbolt the caliper bracket (usually two large bolts) and carefully hang the caliper from the suspension with a piece of wire or bungee cord—do not let it hang by the brake hose. Slide the brake rotor off the hub.

Step 3: Disconnect the ABS Sensor. Trace the wire from the wheel speed sensor to its electrical connector, which is usually located in the wheel well. Press the tab and disconnect it. Note: On some Expeditions, the sensor is integrated into the hub assembly and is replaced with it. In this case, you will simply unplug it from the vehicle harness later.

Step 4: Remove the Hub Assembly. The hub is held to the steering knuckle by four bolts from the rear. These bolts can be very tight and may require a breaker bar or impact wrench. You may need to turn the steering wheel to access them. Remove these four bolts. The hub should now be free. If it's rusted in place, you may need a pry bar or a puller tool to gently separate it from the knuckle. As one owner advised regarding complex jobs: "I asked around various local Indies, these guys, who I already respected, told me they've done this job a half dozen times already, and would put their best Ford engine guy on the job." This underscores the value of experience with this specific vehicle.

Step 5: Install the New Hub. Clean the mating surface on the steering knuckle. Position the new hub assembly onto the studs and hand-start the four new bolts. Torque them to the manufacturer's specification, which is typically between 85-100 ft-lbs, in a crisscross pattern. Reconnect the ABS sensor electrical connector if it was separate.

Step 6: Reassemble. Reinstall the brake rotor and caliper bracket. Torque the caliper bracket bolts to spec. Slide the caliper back onto the rotor and install the caliper guide pins. Torque them properly. Reinstall the wheel, lower the vehicle, and torque the lug nuts in a star pattern to the proper specification (typically 150 ft-lbs).

Step 7: Clear Codes and Test. Start the engine. The ABS light may remain on until the vehicle is driven. Use your OBD-II scanner to clear any stored ABS fault codes. Take the truck for a test drive at low speed in a safe area. The ABS light should turn off after a short distance if the repair was successful. Test the brakes normally.

Parts and Tools Needed

• Primary Part: Front Wheel Hub & Bearing Assembly. A quality OEM-style part is recommended (e.g., Motorcraft BRBF-144). Expect to pay $150-$300 per hub.
• Optional Part: Stand-alone Wheel Speed Sensor (if not integrated with the hub). Motorcraft part number varies by position.
• Tools: Floor jack and jack stands, lug wrench, socket set (including metric sizes), torque wrench, breaker bar or impact wrench, pry bar, OBD-II scanner with ABS capability, wire or bungee cord to hang caliper.
• Supplies: Penetrating oil (like PB Blaster) for rusty bolts, anti-seize compound for hub mating surface (use sparingly).

Real Owner Costs

Repair costs vary significantly between DIY and professional service. For the DIYer, the cost is primarily the part. A single quality front hub assembly can cost between $150 and $300. If you need to purchase a capable OBD-II scanner, add another $100-$200 for a quality unit, though this is a one-time investment. The total DIY cost for one corner typically ranges from $150 to $500 if you need to buy tools.

For professional repair, costs are higher due to labor. Independent shop labor rates are generally lower than dealerships. Replacing one wheel hub assembly at an independent shop might cost $400 to $700 for parts and labor. A dealership will charge more, often between $600 and $900 for the same job. As one owner expressed a common sentiment about dealership service: "This is at an independent, I wouldn't trust my local Ferd dealer to do an oil change without messing something up." This distrust often drives owners to reputable independents, which can offer better value. If the diagnosis points to a simple wheel speed sensor (not integrated), the repair cost will be lower, typically $200-$400 at a shop, as it involves less labor.

Prevention

Preventing premature wheel hub failure is challenging due to its nature as a wear item, but you can extend its life. Avoid impacting curbs or potholes at speed, as sharp shocks can damage bearings and tone rings. Regularly wash your vehicle, especially the undercarriage, in winter to remove road salt, which accelerates corrosion that can seize components and damage sensor wiring. During routine brake service, have your mechanic check for wheel bearing play. Catching a slightly loose bearing early can prevent it from damaging the tone ring and triggering the ABS light.

Listen to your truck. Any new humming, growling, or buzzing noise from the wheels that changes with speed should be investigated promptly. These are early warnings of bearing wear. Finally, ensure any tire or brake work is done carefully. Mechanics can accidentally damage the delicate ABS sensor wire during service. A little vigilance can help ensure your ABS system remains functional for the long haul.

What Owners Say

Real experiences from FORD owners:

Owner Experiences

"I plan on putting the same in my 2022 Tacoma. Mounted the mic to an Expedition Essentials Mounting System." — Artistic_Cabinet8759 (source)

"I had a GMRS radio in my 2020 Tacoma but I can’t remember what brand it was. I plan on putting the same in my 2022 Tacoma." — Artistic_Cabinet8759 (source)

"Idk what year the expedition is but for the most part, everyone I know who has one (only 3 people but still) loves it. One guy bought a 2020 and has put 100k miles on it and only done fluid, brakes, and tires to this point." — dgroeneveld9 (source)

Pro Tips from Owners

💡 "You should always be respectful to a local communities when out in the wild. We drive far enough for trails and don't want to have to drive even further just because of stupidity, inconsideration, and just lack of respect that some may cause." — tacoma16 (source)

FAQ

Q: Can I safely drive my Expedition with the ABS light on? A: You can drive, but with significant caution. Your standard hydraulic brakes will still work. However, the anti-lock braking function is disabled. This means during a panic stop or on slippery roads, your wheels can lock up, causing you to skid and lose steering control. Drive directly to a repair facility or, if doing it yourself, limit driving to necessary trips on dry roads.

Q: How long does it take to replace a wheel hub assembly? A: For a experienced DIY mechanic with the right tools, replacing one front hub assembly typically takes 1.5 to 3 hours. A professional technician at a shop can usually complete the job in 1 to 1.5 hours per wheel. Your first time will likely be on the longer end of the estimate, especially if bolts are rusted.

Q: Is a failing wheel hub a common issue on the 2020 Expedition? A: Based on owner reports, yes, it is a known wear item. As one owner stated, doing wheel hubs around 90,000 miles is "isn't crazy for a heavy SUV anyhow." The vehicle's weight and the integrated nature of the tone ring make the hubs a likely point of failure as mileage accumulates.

Q: DIY vs mechanic – what's recommended for this repair? A: This is a high-intermediate level DIY job. It requires safely lifting the vehicle, dealing with high-torque bolts, and handling brake components. If you are comfortable with brake jobs and have the necessary tools (especially a torque wrench and a way to break loose tight bolts), you can save considerable money. If you are unsure, hiring a trusted independent mechanic, as many owners do, is a wise choice to ensure the repair and your safety are handled correctly.

Q: Could the ABS light be caused by something simple like a fuse? A: It's possible but less common than a wheel speed sensor or hub issue. You can check the ABS fuse in the under-hood power distribution box as a first step. However, a blown fuse often indicates a deeper electrical problem, such as a shorted sensor or module. A diagnostic scan for codes is a much more efficient first step than checking random fuses.

Q: After replacing the hub, my ABS light is still on. What now? A: First, ensure you have cleared the stored fault codes with a scanner. The light will not turn off by itself until codes are cleared. If the light returns after clearing and a short drive, you may have a damaged wiring harness between the sensor and the ABS module, a problem with the new part, or an issue with the ABS module itself. Re-scan for the specific code to guide your next step.