Remove 1/3 cup steak sauce mixture; set aside for later use.
Grill steak 18 min. or until medium doneness (160F), turning and brushing occasionally with remaining steak sauce mixture.
Cut steak across the grain into thin strips.
Heat oil in large skillet on medium-high heat.
Add peppers; cook and stir 3 to 4 min. or until crisp-tender. Stir in reserved steak sauce mixture and steak strips. Spoon steak mixture evenly over tortillas; roll up.