Circuit Description
WARNING: This page is about a different car, the 2003 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.
For circuit description, see CIRCUIT DESCRIPTION under DTC P0120, P0122, P0123, P0220, P0222, P0223 OR P2135. If DTC is stored, difference between VTA1 and VTA2 is out of threshold. Possible cause is faulty throttle position sensor (built into throttle body).