DTC P2100: Throttle Control System - Excessive Pulse Width Modulation Detected: Description
WARNING: This page is about a different car, the 2003 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The Engine Control Module (ECM) opens the throttle blades by applying a pulse width modulated voltage to the throttle valve motor. The ECM reverses the polarity on the throttle valve motor control circuits in order to close the throttle blades. The ECM increases the pulse width as necessary to open the throttle blades. The ECM monitors Throttle Position (TP) sensors 1 and 2 to determine the actual position. If the ECM detects the required pulse width modulation to move the throttle valves exceeds a predetermined value, DTC 2100 sets.