Your LE came stock with 265/65/17 tires. Moving to an 18 inch wheel, you could use 265/60/18 tires (if you can find them), and stay within 1/10th inch circumference of stock configuration. You and your truck will never notice the difference. Any other size tires will be greater or smaller in circumference than original, thus producing speedo error.
As for a CEL while staying within 1/10th inch of spec, I don't see how that's even remotely possible. 1/10th inch is ~ 3/32nds, much less than a tire tread will wear down during its life.
Do your own size comparisons here . . .