ABS Light Stays On in Your GMC Sierra 1500? Here's What to Check

If the ABS warning light on your GMC Sierra 1500 IV (2014–2018) stays on continuously, it means the anti-lock braking system has detected a fault and has shut itself down. You still have normal braking, but the ABS won't help you in a panic stop. The most common culprit is a faulty wheel speed sensor or its wiring.

Most Likely Causes

• Wheel speed sensor failure – The sensor at one of the wheels gets dirty, damaged, or fails internally.
• Wiring harness damage – Rodents, road debris, or chafing can break the sensor wires.
• Tone ring issues – The toothed ring on the axle or hub can crack, corrode, or get packed with debris.
• ABS module fault – Less common, but the module itself can fail or have bad solder joints.
• Low brake fluid or blown fuse – Sometimes a simple fuse or fluid level triggers the light.

What to Check First

Start by scanning for ABS codes with a scan tool that reads chassis codes. The code will tell you which wheel is affected (e.g., C0035 for left front). Then inspect that wheel's speed sensor and harness. Look for cracks, exposed wires, or a loose connector. Use a multimeter to check the sensor's resistance and AC voltage while spinning the wheel. If the sensor looks good, check the tone ring for damage or debris. Also verify the ABS fuses and brake fluid level.

Is It Safe to Keep Driving?

If only the ABS light is on and the brake warning light is off, you can usually drive carefully to a shop. But remember: without ABS, your wheels can lock up during hard braking, especially on wet or icy roads. Avoid panic stops and leave extra following distance. If the brake warning light is also on, or if you feel pulsating or grinding, stop driving and tow it. Ignoring the light can lead to a costly ABS module replacement, so get it diagnosed soon.

This material is AI-generated and for informational purposes only — it does not replace an in-person diagnosis by a qualified mechanic.