The Intake Manifold Tuning Valve (IMT) regulates the pressures between the intake plenums. This valve is also responsible for redirecting intake air into a set of intake channels, in order to change engine flow and performance.
The setting of DTC P2070 OBD2 is due to the Engine Control Module (ECM) detecting that the IMT valve is stuck in the open position. This is determined by the ECM through a position sensor that is built into the valve actuator. Because the valve is made of plastic, it can experience malfunctions due to high temperatures.