If you just got your truck out of service, they might have left your post-cat O2 unplugged, or something else is left unplugged.
However, if it is something going wrong, then Bleed's right.
Go back to the shop. Do not pass go. Do not collect $200.00. If, on your next turn, you roll doubles, you may leave the shop, or pay $50.00 and take your next turn.
