Could there be a restriction on the throttle? Here's what the service manual said for a 2011 (That's the only one I have but the code should be the same?)
"The TAC system sets DTC P2176 when the ECM determines
the zero position of the throttle plate has not been successfully
learned.
At power up, the ECM adjusts the throttle plate to the limp home
position, then begins to move the throttle plate closed.
The ECM monitors and verifies the amount of movement that
occurred. The throttle plate minimum position is held briefly
then verified against the expected minimum and maximum
range of throttle. If the zero position is found within range, then
the position is stored.
If the ECM is not able to learn the minimum position or if the
learning fails four consecutive ignition cycles, the ECM initiates
DTC P2176."
"Air Inlet Interference Test
1. Inspect the air inlet and check for foreign debris and/or
mechanical interference to the throttle plate.
2. Were any issues found?
a. Yes.
b. No. Replace the induction module. See the service
manual."