C0050 on Chevrolet: How to Diagnose & Fix

First-generation Avalanches (2002-2006) can experience unwanted ABS activation during normal low-speed braking. The antilock brake system activates inappropriately, causing a pulsating brake pedal and increased stopping distances when it should not be engaging. The issue is more likely in environmentally corrosive areas where road salt deteriorates the ABS wheel speed sensor wiring and tone rings. This creates a safety hazard as the vehicle takes longer to stop than expected during routine braking.

The 2006-2013 Impala is notorious for internal breaks in the front ABS wheel-speed-sensor wiring harness. The factory routes and clamps the harness such that steering movement repeatedly flexes the wire; the copper conductors fracture inside the insulation while the outer jacket looks perfectly intact, making it hard to spot. The result is intermittent ABS, traction control, and StabiliTrak warnings — often appearing or clearing when the wheel is turned. Left front (C0035) is the most common, but both sides fail.

The wheel speed sensors and their wiring are prone to failure due to the harsh commercial-use environment, causing the StabiliTrak and ABS systems to falsely activate during normal driving. The ABS unexpectedly engages during normal braking, extending stopping distances. The tone rings on the hub bearings also corrode.

The Express uses a sealed front hub/bearing assembly with the ABS wheel speed sensor built into the top of the unit. Two things go wrong. First, on a heavily loaded van the bearing itself wears out and produces a roar or growl that rises with road speed and changes when you sway the van side to side. Second, the seal at the ABS pickup lets water into the hub, which both destroys the bearing from the inside and corrupts the speed sensor signal - so the ABS and traction lights come on before any noise is obvious. Because the sensor is inside the hub, you cannot service the sensor separately; the whole assembly gets replaced. Owners also report a distinct pattern of ABS faults appearing right after a hub replacement when a low-cost assembly was used, which is a real and repeatable trap on this platform. GM previously recalled certain Express vans built without the wheel bearing retaining nut (NHTSA 02V305), which could allow the bearing to separate and disabled the ABS - a related but separate manufacturing defect.

Colorado owners frequently report ABS warning lights, stored wheel speed sensor faults, and low-speed unwanted ABS activation, especially in rust-belt trucks. Corrosion at the front hub sensor mounting area or failing hub-integrated wheel speed sensors can create an erratic signal that the ABS module interprets as wheel slip. This issue is widely documented across GM midsize trucks and often shows up as pulsation or extended stopping distance at parking-lot speeds.

The sealed front hub bearing assemblies on the 2500HD carry heavy front axle weight, and on 4WD trucks they also carry the axle splines and the wheel speed sensor. Owners report failures well before 100,000 miles - forum reports on 2003-2005 2500HD trucks cluster between roughly 40,000 and 90,000 miles - showing up first as a humming or grinding that changes pitch when the truck is loaded into a turn, then as steering wheel vibration and play at the wheel. Because the wheel speed sensor is integrated into the hub, a failing bearing commonly turns on the ABS light and disables ABS and traction control before the noise is obvious, and a fully failed bearing can seize or allow the wheel to separate.

The Traverse is a heavy three-row crossover on a front-drive-biased platform, and the front wheel bearing/hub assemblies are a recurring wear failure across both the Lambda and C1XX generations. The bearing develops a speed-dependent hum or growl that changes pitch when the vehicle is loaded into a turn. Because the wheel speed sensor is integrated into the hub unit, a failing bearing frequently damages or de-tunes the sensor, so the first symptom many owners see is an ABS and StabiliTrak warning light rather than a noise. There is no recall for this on any model year — it is a maintenance-grade failure that arrives earlier and more often than owners expect on this nameplate.