I've always had this nagging question about electronic throttle bodys. Do they simply rely on spring tension to close or can the driver (PCM) reverse the polarity and force it shut. Well wonder no more, at least for this 07 F150 5.4. I was poking around under hood to verify another repair and thought I would back probe the two driver wires to the throttle body as well as put the low amp probe around one of the driver wires. Yep, it definitely can drive the throttle in either direction. Notice the current direction change on the amp probe when the pulse width changes from one wire to the other.