Difficulty Steering in Cold Weather
Some customers of 2013–2017 Buick Encore and Chevrolet Trax models with an electric power steering system (RPO NJ1) may encounter difficulty steering during colder temperatures. This may be accompanied by a knocking and/or clicking sound. 

The condition may stem from water intrusion in the steering gear input shaft that is freezing and/or causing corrosion. To correct the problem, check for water and corrosion at the power steering gear pinion housing. Note that a small amount of rust (one or two spots) is normal. 

If water intrusion or more than a couple of rust spots are found, replace the intermediate steering shaft boots (seals) and the steering gear.

Caption: Excessive corrosion on a steering gear input shaft can cause difficult steering.