Model-level reading
What changes the warranty calculation
The GMC Terrain file contains 11 model years and 1,354 submitted complaints. The middle year in this set has 133 reports, giving each annual count a model-specific reference point.
2015 has the largest complaint count in the current file at 295. That does not establish a defect rate because sales volume and vehicle age differ across years.
Engine replacement or major internal repair carries the highest midpoint parts estimate among the applicable repair categories at $7,000. I would check whether that system remains under factory coverage before pricing an extra contract.
